Australian Curriculum Science: Year 4 - Ages 9-10

RIC-6697 4.5/1228

Australian curriculum science (Year 4) Published by R.I.C. Publications® 2011 Copyright© R.I.C. Publications® 2011 ISBN 978-1-74126-991-8 RIC– 6697

Copyright Notice

Titles in this series: Australian curriculum science (Foundation) Australian curriculum science (Year 1) Australian curriculum science (Year 2) Australian curriculum science (Year 3) Australian curriculum science (Year 4) Australian curriculum science (Year 5) Australian curriculum science (Year 6) Australian curriculum science (Year 7)

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This master may only be reproduced by the original purchaser for use with their class(es). The publisher prohibits the loaning or onselling of this master for the purposes of reproduction.

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Internet websites In some cases, websites or specific URLs may be recommended. While these are checked and rechecked at the time of publication, the publisher has no control over any subsequent changes which may be made to webpages. It is strongly recommended that the class teacher checks all URLs before allowing students to access them.

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Foreword Australian curriculum science Foundation to Year 7 is a series of books written specifically to support the national curriculum. Science literacy texts introduce concepts and are supported by practical hands-on activities, predominantly experiments.

All Science Understanding and Science as a Human Endeavour substrands for each level are included. Science inquiry skills and overarching ideas underpin all topics.

Australian curriculum science is a complementary resource to the previously released R.I.C. series, Primary Science.

Australian curriculum science – Foundation Australian curriculum science – Year 1 Australian curriculum science – Year 2 Australian curriculum science – Year 3 Australian curriculum science – Year 4 Australian curriculum science – Year 5 Australian curriculum science – Year 6 Australian curriculum science – Year 7

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Titles in this series are:

Teachers notes ................................................................. iv – vi

What are materials scientists? ...........................................46–48

Science inquiry skills overview ................................................vii

Inventions and devices research............................................. 49

Report format ........................................................................viii

Earth and space sciences ..............................................50–65

Basic experiment format ......................................................... ix

What is weathering?..........................................................50–52

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What is the life cycle of a sunflower? ....................................2–4

Where does soil come from? ............................................54–56

Bean seeds experiment ............................................................ 5

Soil testing experiment ........................................................... 57

What is the life cycle of a frog? .............................................6–8

What is erosion? ...............................................................58–60

Amphibian report..................................................................... 9

Extreme weather research project.......................................... 61

What is the life cycle of an elephant? ................................10–12

How do farming practices affect erosion? .........................62–64

Mammal life cycle quiz........................................................... 13

Plants and erosion experiment ............................................... 65

How does environment affect life cycles? ..........................14–16

Physical sciences ..........................................................66–81

Ladybug life cycle wheel ......................................................... 17

How are objects moved by forces?....................................66–68

How do living things get energy to live? ............................18–20

Pushing and pulling experiments ........................................... 69

What happens when plants are no longer living? .................... 21

How do forces change movement and speed?...................70–72

Why do living things in a habitat interact? .........................22–24

Force and distance ................................................................. 73

Researching symbiosis ........................................................... 25

What are magnets? How do they work? .............................74–76

What are food chains? ......................................................26–28

What does a magnetic field look like?..................................... 77

Observational report .............................................................. 29

What is friction? ...............................................................78–80

Why are living things endangered?....................................30–32

Testing friction ....................................................................... 81

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Weathering investigations ....................................................... 53

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Biological sciences .........................................................2–33

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Endangered living thing report ............................................... 33 Chemical sciences ........................................................34–49 What properties do materials have? ..................................34–36 Testing! Testing! 1, 2, 3 ,4!...................................................... 37 Why search for new materials? .........................................38–40 Can you make a material stronger?......................................... 41 What is insulation? ...........................................................42–44 The best thermal insulators and conductors........................... 45 R.I.C. Publications®

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Teachers notes Each book is divided into four sections corresponding to the four substrands of the Science Understanding strand of the curriculum. Shaded tabs down the side of each book provide a quick and easy means to locate biological sciences, chemical sciences, Earth and space sciences or physical sciences substrands.

Science as a Human Endeavour units or questions, as set out in the Australian Curriculum, are included in all substrands.

Science inquiry skills are included in all units. The skills utilised are listed on each teachers page.

The six overarching ideas (Patterns, order and organisation; Form and function; Stability and change; Scale and measurement; Matter and energy; and Systems) underpin each science literacy text page and are included as much as possible throughout the comprehension pages.

Each substrand is divided into a number of four-page units, each covering a particular aspect and following a consistent format.

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The four-page format of each unit consists of: • a teachers page

• student page 1, which is a science literacy text about the concept with relevant diagrams or artwork

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• student page 2, which includes comprehension questions about the literacy text • student page 3, which involves a hands-on activity such as an experiment.

Teachers page

The first page in each four-page format is a teachers page which provides the following information:

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FOUR-PAGE FORMAT

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• A shaded tab gives the Science Understanding substrand.

• The lessons provides information relating to implementing the lessons on the following student pages.

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• The content focus (the particular aspect of the unit covered in that set of four pages) is given.

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• The inquiry skills focus covered within the four pages is set out.

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• The title of the four-page unit is given.

• Answers and explanations are provided where appropriate for student pages 2 and 3 (the comprehension questions relating to the text and the final activity in the set of four pages).

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• Preparation states any material or resources the teacher may need to collect to implement a lesson, or carry out an experiment or activity.

• Background information, which includes additional information for teacher and student use and useful websites relating to the topic of the section, expands on the unit.

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Teachers notes FOUR-PAGE FORMAT (continued) Student page 1 The second page in the four-page format is a science literacy text which introduces the topic. This page provides the following information:

• A shaded tab down the side gives the Science Understanding substrand.

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• The title of the unit is given. This is in the form of a question to incorporate science inquiry skills and overarching ideas.

• Instructions are given for reading the text.

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• The science literacy text is provided.

• Relevant diagrams or artwork enhance the text, or are used to assist student understanding of the concepts.

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Student page 2

The second student page consists of a series of questions or activities relating to the literacy text. They aim to gauge student understanding of the concepts presented in the text. Many of these questions relate to overarching ideas relevant to that age level as stated in the Australian Curriculum Science.

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• The title, which is the same as the text page, is given.

• A shaded tab gives the Science Understanding substrand.

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• Questions or activities follow. These relate to the text on the previous page.

Where relevant, a question relating to Science as a Human Endeavour may be included as the final question on this page.

This assists in keeping the strands interrelated. This question is indicated by the icon shown to the left.

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Teachers notes FOUR-PAGE FORMAT (continued) Student page 3 The third student page provides a hands-on activity. It may be an experiment, art or craft activity, research activity or similar.

• A shaded tab gives the Science Understanding substrand.

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• The title is given. This will be different from the previous two pages, but will be a related to the concept focus of the unit.

• An adapted procedure for an experiment, craft activity or a research activity is given.

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Science as a Human Endeavour units and questions

Those four-page units which are related specifically to Science as a Human Endeavour substrands are indicated by the icon shown.

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Where Science as a Human Endeavour questions occur within Science Understanding units, they are also indicated by the use of the icon. Explanations and answers relating to these questions are given on the appropriate teachers page.

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Science inquiry skills overview Biological sciences PAGES

Questioning and predicting

Planning and conducting

Processing and analysing data and information

Evaluating

Communicating

2–5 —

6–9

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10–13 14–17 18–21

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26–29

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30–33

PAGES 34–37

38–41 42–45

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22–25

Chemical sciences

Questioning and predicting

Planning and conducting

Processing and analysing data and information

Evaluating

Communicating

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46–49

Questioning and predicting

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PAGES 50–53

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54–57 58–61 62–65

Planning and conducting

Processing and analysing data and information

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Earth and space sciences Evaluating

Communicating

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PAGES

Questioning and predicting

Planning and conducting

Processing and analysing data and information

Evaluating

Communicating

66–69 70–73 74–77 78–81

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Report format Title Classification What is it?

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Description

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Conclusion What I think about it.

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Experiment format Title Goal Materials

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Steps

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Results

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Conclusion

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What is the life cycle of a sunflower?

Inquiry skills focus:

The lessons

Life cycle of a typical flowering plant

• Pages 3 and 4 should be used together.

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

• Before reading the text, discuss what the term ‘life cycle’ means.

Ensure students understand terms such as ‘germination’, ‘nutrients’ and ‘photosynthesis’.

• Students could work individually or in pairs to complete the experiment on page 5. Note: If the sponge starts to dry out, add a little water and reseal the bag. Don’t stick bags directly to a window as it can get too hot during the day and too cold at night. There must be gaps between the staples.

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• It is important each group of students uses three of the same seed for the experiment so a fair test is achieved. One or more of the seeds may not germinate or grow as well as the other(s).

• Plants can reproduce from seeds, spores or by using parts of the plants themselves; e.g. stem cuttings. Most produce seeds dispersed by wind, water, people or other animals. When the seeds have the right conditions for growth—i.e. space, food, water, temperature and light—they germinate.

• Students will need to wait until the seeds germinate and leaves first appear before completing Questions 1 and 2 on page 5. They should observe their plants until they begin to wilt. This will indicate the food stored in the seed has been used up and the plant will die unless it is planted in soil to get nutrients.

• For fertilisation to occur, pollen must travel from the male part (the anther in the stamen) to the female part (the stigma in the pistil).

Some flowers self-pollinate, while others need insects, birds or other animals to transfer pollen from one flower to another. Pollination of the flower leads to the making of more seeds and the cycle continues.

Non-flowering plants such as ferns and mushrooms reproduce through spores, usually found on the underside of the plant.

Answers Page 4 1.

2.

3.

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It means a seed starts to grow. (e), (c), (a), (d), (b) Both contain water and nutrients from the soil.

Answers should indicate the plant would not be able to reproduce as it couldn’t make seeds.

5. Plants – germinate, have seeds, make own food Both – grow, die, reproduce Animals – are born, lay eggs Science as a Human Endeavour question Nature and development of science/Use and influence of science Possible answers: sunflower oil in cooking; margarine (as a spread); sunflower seeds on top of salads, in grain/seed breads, in trail mixes.

• In the section about leaves, ‘photosynthesis’ is mentioned. Explain to the students that in this process plants use sunlight, water and carbon dioxide from the air to make glucose, a form of sugar, as food for energy and growth. Photosynthesis only occurs in the leaves of green plants. Green leaves contain a pigment called ‘chlorophyll’ which helps with the process.

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• Some useful websites include: − <http://www.bbc.co.uk/schools/scienceclips/ages/7_8/plants_ grow.shtml>

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− <http://www.youtube.com/watch?v=JbyImpvrO74> (Time-lapse bean sprout germination) − <http://www.exploringnature.org/db/detail. php?dbID=32&detID=2301> (Life cycle flip book birds, butterflies, frogs, plants)

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1. Teacher check 2. Unless there are variations, each bean plant will grow at a similar rate. Teacher check explanation.

3. The students will find that different bean seed varieties sprout and grow at different rates—their life cycles are of different lengths.

Some of the same types of bean seeds will also vary in growth rate, due to size, health, lack of water, less sunlight/warmth.

4. Teacher check

• A fair test occurs when only one factor (or variable) changes at a time while all other conditions are kept the same.

Preparation

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Content focus:

• Obtain a sample sunflower if possible, or a coloured illustration for students to refer to while discussing the life cycle described on page 3.

• Sunflower products such as sunflower oil and seeds, margarine containing sunflower oil and grain bread containing sunflower seed would be useful to display and to help students answer the last question on page 4.

• Collect the materials listed for the experiment on page 5. Bean seeds could include black-eyed, lima, haricot or climbing varieties.

Magnifying glasses could be supplied to enable the parts of the growing bean seeds to be studied in more detail. Fishing line or thin rope could be strung along in front of a sunny window for students to hang their bean seed bags on.

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Read the text.

The beginning ...

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A small shoot appears above the soil. Then the stem begins to grow.

It carries water and nutrients from the roots to the plant.

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A sunflower seed falls to the ground.

It will start to develop, or germinate, when the weather is warm and the soil is damp.

A root develops and grows down into the ground. It holds the plant in place. The root allows the plant to grow by taking in water and nutrients from the soil.

The leaves appear. They make the nutrients the plant requires to continue growing. It does this by using sunlight, water and the carbon dioxide it gets from the air. This process is called photosynthesis.

The petals and leaves fall off as the flowers die.

Seeds begin to form inside each flower.

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Flowers begin to develop. These contain pollen and ova. In the future, they will combine to produce the seeds which will eventually germinate and grow into new plants.

Sunflower petals are bright yellow. The plants are fully grown in about three months.

They can grow up to three metres tall.

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Biological sciences

What is the life cycle of a sunflower? – 1

What is the life cycle of a sunflower? – 2 1. What do you think the word ‘germinate’ means?

2. What happens after seeds germinate? Write the numbers 1 to 5 to show the correct order.

r o e t s r eeach flower. Boo (b) Seeds begin to growp inside u k S (c) A small shoot appears above the soil. (a) The leaves begin to grow.

(d) Flowers begin to grow. (e) A root appears and grows down into the soil.

3. How are the roots and stems of a sunflower similar?

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C.Publ i cat i ons •happen f orifr vi ewdidn’t pu r pflo sesonl y• What would ae sunfl ower have owers?

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Biological sciences

Use the text on page 3 to complete the following.

5. Think about what is the same and what is different about animal and plant life cycles. Write each of these things in the correct place.

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They: grow, die, reproduce, germinate, are born, lay eggs, have seeds, make own food.

Plants only

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Scientists have discovered that sunflower seeds are full of Vitamin E and other nutrients. Find out ways they are used in the foods we eat.

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Bean seeds experiment Biological sciences

Do bean seeds grow at the same rate?

Materials: • three of one type of bean seed

• marker

• container for soaking beans

• 1 medium zip-lock bag

• scissors

• kitchen sponge cloth

• water

• stapler

r o e t s Bo r e p ok Procedure: u Soak beansS in water overnight.

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• clothes peg/bulldog clip

Cut out a section of sponge cloth so it will fit into the bag.

Staple a line of about five staples 4 cm from the bottom of bag.

Add enough water to sponge to make it wet.

Place beans in bag above staples. Label the bags underneath the beans A, B, C.

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Seal bag and label it with your name, the date and the type of beans.

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Predictions, results and conclusions: 1. Record the following.

Bean A

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Use peg to hang it in a sunny, dry place. Observe.

Bean B

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Bean C

Why?

3. Explain what happened as the beans grew.

4. Compare how your beans grew with someone who used a different type of bean. Record your observations on the back of this sheet.

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What is the life cycle of a frog?

Inquiry skills focus:

The lessons

Life cycle of a frog

• Pages 7 and 8 should be used together.

Questioning and predicting Planning and conducting Processing and analysing data and information Communicating

Background information

• Discuss vocabulary such as ‘life cycle’, ‘larva (‘larvae’)’, ‘embryo’, ‘gills’ and ‘algae’.

• The students’ task on page 9 is to choose an amphibian to write a brief report on. They should concentrate on the stages of its life cycle. Explain that amphibians include frogs, toads, salamanders and newts. (Caecilians are also amphibians.) They should use reference books and the internet to find information. Drawings and diagrams can be copied or colour photographs attached to their report.

Students may like to choose an amphibian from the following list:

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• Amphibians are cold-blooded vertebrates (animals with backbones) that live part of their life in water (or watery places) and part on land. Most amphibians have smooth, moist skin. Frogs are arguably the most well-known amphibians. Others are toads, salamanders, newts and caecilians (worm-like creatures).

− Frogs–Goliath frog, green-eyed tree frog, poison dart frog (there are several types), green and golden bell frog, corroboree frog, pillow frog, Amazon horned frog, tomato frog − Toads–cane toad, oriental fire-bellied toad, common toad, African giant toad

• Amphibians change from breathing through gills in the larval stage to breathing through lungs as adults. They also change from being herbivores to carnivores. Depending on their size and species, adult amphibians eat insects, molluscs, worms, other amphibians and even small mammals like mice, and smaller birds.

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− Salamanders–spotted salamander, Mexican axolotl, tiger salamander, Chinese giant salamander, cave salamander − Newts–warty newt, alligator newt, Japanese fire-bellied newt, emperor newt, alpine newt

• Not all eggs or larvae will make it to the adult stage. Predators such as ducks, fish, insects and other water creatures eat the eggs. As larvae, they still face danger such as being eaten by larger water animals or dying if their water source dries up. Note: The larvae of frogs and toads are called tadpoles.

Answers

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• Some useful websites include:

1. It means it lives part of its life in water and part on land.

2. (a) Female frogs lay eggs in wet places. (b) Frog spawn is a large clump of eggs. (c) A tiny tadpole hatches from each egg.

3. They hide their eggs in damp vegetation or lay them in spawns which are too big and slippery for other creatures to eat.

4. A male is trying to attract a female.

5. Answers should indicate that the frog spawn would get separated by the turbulence which would enable creatures to eat the eggs.

6. Older tadpoles are developing lungs and need to come up to the surface to breathe air.

Science as a Human Endeavour question Nature and development of science Teacher check

− <http://www.youtube.com/watch?v=ce5_Vk_yNcY> (Animated life cycle of a frog)

− <http://www.kidcyber.com.au/topics/frogdanger.htm> (This site gives information about endangered species of Australian frogs and how to make a ‘frog bog’ to encourage frogs to inhabit the area.)

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Content focus:

− <http://animals.nationalgeographic.com/animals/amphibians. html> (Photographs, information and video clips of amphibians) Preparation

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• Reference books or the internet will need to be available for students to research the life cycle of a chosen amphibian on page 9.

Page 9

Teacher check

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Read the text.

A frog is an amphibian. Most amphibians spend their early life in water and most of their adult life on land. Nearly all types of frogs begin life as eggs laid in water.

When a frog egg hatches, the larva is known as a tadpole. The tadpole gradually changes as it grows and eventually becomes a frog.

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An adult female frog lays her eggs in calm water or in wet places among vegetation. The plants there help to hide and protect the eggs. Some eggs are laid in a large clump, called frog spawn.

This large, slippery clump is usually too big to be eaten by other creatures living nearby. Some frogs stay with their eggs to look after them as they develop. Others lay their eggs and leave.

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Egg

Inside each egg, an embryo forms and slowly begins to look more like a tadpole.

The embryo eats the yolk surrounding it in the egg. Tiny tadpoles are ready to hatch in 6 to 21 days.

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remain hidden. The rest of the yolk provides them with the food they need. At this stage, they have poorly developed gills, a mouth and a long tail. After about a week, the tadpoles begin to swim around and feed on algae.

From about four weeks, they begin to change. The tadpoles develop tiny teeth and start to grow back legs.

A bit later, front legs begin to form. Their tails become smaller and their lungs develop. Now and then they swim to the surface to breathe in air. They eat plants, decaying animal matter and some even eat other frogs’ eggs and smaller tadpoles.

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C.Publ i cat i ons The tiny tadpoles (larvae) move very little for the first week •f orthemselves r evi ew pur pos etry stoonl y• or two. They attach to floating plants and Larva

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After about 12 weeks, the tadpoles have become tiny frogs. They have lungs, legs, a frog’s head and no tail. They now live mostly on land, eating animals such as insects and worms.

Adult Adult frogs may live for one or several years. Generally, the larger the species of frog, the longer they live. When frogs are ready to mate, the male frogs use loud croaking noises to attract the females. Then the cycle begins again.

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Biological sciences

What is the life cycle of a frog? – 1

What is the life cycle of a frog? – 2 1. A frog is an amphibian. What does this mean?

2. These sentences about the egg stage are wrong.

r o e t s Bo r e (a) Female frogs lay eggs on dry land. p ok u S Rewrite them so they are correct.

(b) Frog spawn is one large egg.

(c) A tiny frog hatches from each egg.

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3. Describe two different things frogs do to try to protect their eggs.

4. What would most likely be happening if you heard a frog croak?

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Use the text on page 7 to complete the following.

5. What do you think would happen if a frog laid its eggs in rough water?

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Scientists are concerned because research has shown there are fewer and fewer frogs in many parts of the world. Find out if this is true in your country and write a report.

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Name of amphibian: Where it is found: Notes, sketches and diagrams about each stage of its life cycle:

r o e t s Bo r e p ok u S Larva

Adult

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Egg

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Biological sciences

Amphibian report

What is the life cycle of an elephant?

Inquiry skills focus:

The lessons

Life cycle of a mammal

• Pages 11 and 12 should be used together.

Questioning and predicting Planning and conducting Processing and analysing data and information Communicating

Background information

• Discuss vocabulary such as ‘life cycle’,’ adolescent’ and ‘matriarch’.

Answers Page 12 1. Possible answers: give birth to live young/don’t lay eggs (except for monotremes–platypus and echidna)/feed their young milk/mostly have three main stages in life cycle/look after and teach their young 2. Answers should indicate that it takes longer for a baby elephant to grow inside the mother because it is so much bigger than a dog and more developed at birth than a puppy.

3. (a) It must stand up. (b) So it can drink its mother’s milk and walk with the herd in the wild.

4. They teach it to use its trunk for feeding, drinking water and bathing.

5. When it stops drinking milk entirely and eats only vegetation; between 5 and 10 years old.

6. Possible answers: young bulls play-fight/bulls leave the herd and cows stay with the herd Science as a Human Endeavour question Nature and development of science Teacher check

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• There are three species of elephant: African, African forest and Asian (also known as Indian). The first mentioned is the largest.

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• A newborn calf weighs between 77 and 113 kilograms. Its height is about 90 cm from the shoulder to the ground. When a calf is born, all the adult female elephants in the herd crowd around the mother and touch her calf. The calf drinks up to 11 litres of milk each day.

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• If, for some reason, a calf’s mother dies, the other elephants look after the calf. All young calves are protected by the herd. A herd is made up of female elephants and baby and adolescent bulls who have not yet left the herd. All the adult females are related.

• An elephant’s life span is largely determined by its teeth. It usually grows six sets during its lifetime, the final set appearing about aged 40. When these teeth wear down and it can no longer chew, it gradually dies of starvation.

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• Some useful websites include:

Page 13

− <http://kids.nationalgeographic.com/kids/animals/ creaturefeature/african-elephant/>

− <http://fohn.net/elephant-pictures-facts/index.html> Preparation

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• Reference books or the internet will need to be available for students to research the answers to the questions on page 13.

• Some useful websites for answers for page 13 include:

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− <http://www.defenders.org/wildlife_and_habitat/wildlife/ dolphin.php>

Chimpanzee

Polar bear

on average, 12 mths

8 mths

8 mths

usually 1

usually 1

usually 2

calf

no special name

cub

18 mths to 5 yrs, but eat small fish as well by 6 mths

4 to 5 yrs

18 mths to 2 1/2 yrs

takes newly born calf to surface to breathe, teaches it to swim and catch fish

what foods are safe to eat, how to use tools such as sticks to catch termites

keeps newborn in an ice den for four months, how to hunt for seals, other survival skills

until about 5 years of age

for up to 10 years, may stay in same group permanently if female

about 2 1/2 yrs

on average 25 yrs, can live to 40

50 yrs in wild, 60 in 15 to 18 yrs in wild, captivity 35 to 40 in captivity

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− <http://www.kidcyber.com.au/topics/dolphin.htm>

− <http://www.ehow.com/how-does_4566867_dolphins-caretheir-young.html>

− <http://www.oregonzoo.org/Cards/Primates/chimpanzee.htm> − <http://kids.nationalgeographic.com/kids/animals/ creaturefeature/chimpanzee/>

− <http://www.kidcyber.com.au/topics/polarbear.htm>

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Content focus:

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Read the text.

An elephant is the largest living land mammal. Mammals give birth to live young, instead of laying eggs as many animals, such as birds, reptiles and insects, do. Female mammals need to care for their young and to feed them the milk they produce. There are three main stages in an elephant’s life cycle: baby– adolescent–adult.

r o e t s Bo r e p ok u Scalled a cow, usually gives birth to only one calf at a time. A A female elephant, Baby

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A baby elephant, called a calf, develops inside its mother for 22 months. That is the longest time for any land animal to be pregnant! Among other mammals, humans are pregnant for 9 months, while a dog is pregnant for only 9 weeks.

newborn calf has ginger coloured hair over its head and back. It loses this as it grows older. Its mother uses her trunk to help the newborn stand up. The calf must do this right away so it can reach and drink its mother’s milk. In the wild, it also needs to walk along with the rest of the herd because they are constantly on the move and won’t stay long in the one place. The calf drinks about 11 litres of milk each day. After it grows teeth, at about 3 years of age, it starts to eat grass and other vegetation.

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C.Publ i cat i ons f or r e i ew p ur po se so nlook l yafter • it. The The calf’s• mother and thev other adult females in the herd help calf learns how to use its trunk for feeding, drinking water and bathing.

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Adolescent

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An elephant is called an adolescent when it stops drinking milk entirely and eats only vegetation. This happens between 5 and 10 years of age.

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Male elephants are called bulls. Young bulls play-fight by charging each other and making a lot of trumpeting noises with their trunks. They leave the herd at about 13 to 15 years of age to form another herd with other young bulls.

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Female elephants, the cows, stay with the herd all their lives. The herd is ruled by the oldest female, called the matriarch.

Adult An elephant is an adult at about 18 years of age. Male and female elephants begin to mate at about 20 years of age. A cow will have six or seven calves during her lifetime. She stops having calves at about 50 years of age. An elephant can live until it is about 70.

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Biological sciences

What is the life cycle of an elephant? – 1

What is the life cycle of an elephant? – 2 1. What are two characteristics mammals have in common?

2. Why do you think a female elephant is pregnant for 22 months and a dog for only 9 weeks?

r o e t s Bo r e p ok u S 3. (a) What must a newborn calf do as soon as it is born?

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(b) Why must it be able to do this?

4.

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5. When does an elephant become an adolescent?

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Use the text on page 11 to complete the following.

o c . c e herthe life st r 6. Describe one difference between o super of a bull and a cow.

Visit this website to discover facts zoologists have discovered about the uses of an elephant’s trunk. <http://www.african-safari-pictures.com/elephant-trunk.html> AUSTRALIAN CURRICULUM SCIENCE

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Each of the animals below is a mammal. See if you can find information to answer the questions about each mammal’s life cycle.

Dolphin

Polar bear

r o e t s Bo r e p ok u S

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How long is the mother pregnant?

Chimpanzee

How many babies are born at a time?

Name of young

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What are some things the mother does for, or teaches, her young?

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How long does it feed its young milk?

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How long do the young stay with their mother?

How long can this animal live?

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Biological sciences

Mammal life cycle quiz

How does environment affect life cycles?

Inquiry skills focus:

The lessons

Life cycles and environmental factors

• Pages 15 and 16 should be used together.

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

• Discuss the environment and some of the ways in which it can change.

• Explain that ladybugs are also known as ladybirds or ladybird beetles and brainstorm what students know about them and where they live.

• Introduce the activity on page 17.

• Encourage the students to make notes and to collect or copy appropriate drawings and diagrams to use in their ladybug life cycle wheels.

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• Students can research individually or in small groups. Students are expected to include egg stage, larva stage, pupa stage and the adult stage in their ladybug life cycle wheel.

• There are many environmental factors that can affect the life cycle of plants and animals. These include factors such as temperature, wind speed, fire, flood, drought, volcanoes, earthquakes, pollution and interaction with other plants and animals.

• Provide opportunities for students to demonstrate and discuss their completed life cycles wheels.

• The seed stage of a plant’s life cycle can be its least vulnerable and usually provides it with its greatest chance of surviving environmental changes. This is often achieved by delaying germination until the environment is more suitable.

Answers Page 16

• Similarly, some animals can adjust their life cycles and may for example not produce offspring in times of environmental change if this has resulted in a poor supply of food.

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1. A caterpillar can change the time it spends in the different stages of its life cycle. For example, time can be shorter in the caterpillar and longer in the pupa stage.

2. Life cycles can change to protect a species so it will survive.

3. Summer; When their environment is hot and moist, their life cycle is shorter so there are more of them.

4. Farmers build dams so they can flood their land because most of a rice plant’s life cycle needs to be spent in water.

5. Snails will seal themselves on a surface for protection and delay their life cycle until the soil is better for laying their eggs in.

6. Possible answer: Seeds blown a long way could land in a place where they can’t germinate or grow.

Science as a Human Endeavour question Nature and development of science Teacher check Differences include: botanists are interested in plants and zoologists in animals. Similarities include they both study living things, are interested in research, write reports, share their knowledge, are interested in how things grow, develop and reproduce

• Some further examples of animal adaptation of life cycles include: Worms whose life cycles are adapted in response to the amount of daylight available, and striped bass, whose spawning relates to the amount of dissolved solids in the water.

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• Changes in the environment may affect competition between species.

Those more able to adapt their life cycles may thrive to the detriment of other species. Flowering times is one example of this, relating to temperature. Changing temperatures have been known to cause annuals to flower before perennials, allowing the animals to invade the perennials’ space.

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Content focus:

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• Some useful websites include:

− <http://www.kidskonnect.com/subject-index/15-science/87-lifecycles.html>

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− <http://www.ladybug-life-cycle.com/> Preparation

o c . che e r o t r s super Page 17

• Reference books or the internet will need to be available for students for research and to answers the questions on page 17.

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1.–2. Teacher check 3. Yes 4. No 5.–6. Teacher check

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Read the text. which depends on floodwaters. Any land used for growing rice needs to be flooded for most of its life cycle.

When humans cultivate rice they dam streams and continually release enough water to flood the rice paddies to a depth of between 5 and 25 centimetres.

r o e t s Bo r e p o Fire, often started by lightning, is a u k are plants like natural force. There S pine trees whose life cycles depend

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The life cycles of plants and animals do not happen in exactly the same way every time. This is because some species’ life cycles can change when their environment changes. If it is unusually cold, a moth will lay its eggs early because they will survive very low temperatures better than the adult will. In the same way, the caterpillar can become a pupa earlier, because the pupa will survive the cold and the caterpillar won’t.

on fire. Fire releases seeds from their seed cases. Then they fall to the ground, germinate and grow. Some plants have flammable oil-coated leaves that increase the intensity of the fire, destroying other plants.

Their seeds then grow without any competition.

Others have cones sealed with a resin that fire melts, releasing its seeds. Fire, high in a canopy, can let in the light needed by the seedlings of some plants to grow.

Some species survive because they can adapt their life cycles to any changes in their environment. But species that can’t adapt could be destroyed if their environment changes too much.

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House mites are an insect pest.

They love hot, moist air. When their environment is like this, they shorten their life cycles so there are many more house mites around.

This is not a change that anyone welcomes! However, refrigerated air conditioning lowers the temperature as well as the humidity of the air. So air conditioning has become a very effective way of changing the house mites’ environment and reducing their numbers.

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o c . che e r o t r s s per The environment can be changed u

Drought can affect the life cycles of many creatures. Snails do not breed unless there is moist soil for them to lay eggs in. They can seal themselves to walls until conditions improve. This can be for a very long time.

in many ways by natural events like floods, fires, droughts and strong winds, as well as by human actions.

The seed dispersal and life cycles of many plants depend on wind. Seeds are often blown long distances.

They wait there until there is enough moisture for germination and the beginning of a new life cycle.

The life cycles of many plants are affected by floodwater covering or sweeping them away. Rice, which is the staple diet of half the world’s population, is a semi-aquatic plant R.I.C. Publications®

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Biological sciences

How does environment affect life cycles? – 1

How does environment affect life cycles? – 2 1. Explain how a caterpillar’s life cycle can change when its environment changes.

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2. Why do living things need to change their life cycles when their environment changes?

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3. Would there be more house mites around in summer or winter?

Why?

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4. Explain why rice farmers need to build dams on their properties.

5. What happens to the life cycle of a snail when the soil is hot and dry?

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Use the text on page 11 to complete the following.

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o c . cofh e 6. Why do you think some the seeds blown long distances by strong wind r e o wouldn’t germinate and grow? r st super

Botanists and zoologists are both concerned about the life cycles of living things. Research to find similarities and differences in the work of these two different areas of sciences.

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1. Research information about ladybugs and their life cycles and make some notes.

2. Draw a picture and write some information about each of the stages on the life cycle wheel.

3. Will it matter in which order you put the stages?

Yes

No

r o e t s Bo r e p ok 6. What is the mostu interesting fact you learnt about ladybugs?

S 4. Will it matter which stage you start with?

Yes

No

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5. Cut out the wheels, colour the top and put them together using a split pin.

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o c . che e r Ladybug o t r s super life cycle

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Biological sciences

Ladybug life cycle wheel

How do living things get energy to live?

Inquiry skills focus:

− Explain that students will work with a partner to plan an investigation to find what causes things to rot at different rates.

(Choose heat, water or air.)

Energy for living things Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

− Discuss fair tests and remind students that only one thing in an experiment can change while everything else must stay the same.

• All living things need energy to live, move and grow.

− Ask students to discuss, collect and record the materials they’ll need and to write their prediction on their activity sheet. They should select two bags with the same food, and plan and write the steps they will take as follows: Air: Seal one bag, remove food from other and leave exposed to air before sealing it in bag later in day. Heat: One bag in fridge, other in a warm place. Water.

Use dehydrated fruit without preservatives in one bag and fresh food in other.

• On Earth, the sun is the source of energy for almost all life forms, which can be divided into three mutually dependent groups: producers, consumers and decomposers.

− They should record the type of food that is in their plastic bags and the two different factors, e.g. cold and room temperature, air and no air, or water and no water, on their activity sheet.

• Producers are the only living things capable of producing and storing energy. They do so by a chemical reaction using energy from the sun. All life on Earth is directly or indirectly dependent on the energy stored in plant tissue. Conversely, many producers depend on consumers for pollination and for breaking matter down into a form they can use.

− Observations and data can be collected daily for five days and the results, conclusion and evaluation sections completed.

Background information

r o e t s Bo r e p ok u S Answers Page 20

• Animals are consumers. They can only source the energy they need indirectly from plants and/or other animals.

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1 (a) Plants make their own energy using energy from sunlight, water, minerals and carbon dioxide. (b) producers 2. The energy animals need must move from one organism to another.

They get their energy by eating plants and/or other animals.

3. No. Some animals couldn’t survive because they eat other animals which get their energy by eating herbivores or animals that have eaten herbivores.

4. Teacher check. Any plants can be listed for (a) and any animals listed in (b).

5. Decomposers break down dead animals and plants and can make the soil more fertile for producers to use.

6. Similarities include: They both consume plants and/or other animals. They are not able to get their energy directly from the sun. Differences include: Decomposers consume dead plants and animals. Some decomposers are so small you can’t easily see them.

Decomposers help producers by making soil more fertile.

7. (a) Yes (b) No. They are too small.

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• Decomposers (bacteria and fungi) are a particular type of consumer.

They play a crucial role in energy flow but are sometimes overlooked by students. This may be because many fungi can only be seen in colonies and because bacteria are too small to be visible. Bacteria can be both beneficial (e.g. in breaking down waste) and harmful (e.g. by causing disease).

• One useful website is <http://www.nhptv.org/natureworks/ nwep11b.htm>.

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Content focus:

Preparation

• The following materials should be prepared and available for each student group for the experiment on page 21:

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− Two sealable plastic bags each with an equal quantity of the same fruit slices or damp bread in it − Dehydrated fruit with no preservatives − Markers − Water − A refrigerator

Page 21

Teacher check Decomposition (rotting of food) needs water, air and heat to be most effective.

The lessons • Pages 19 and 20 should be used together.

• Introducing the decomposer investigation on page 21: − Discuss what happens to dead plants and animals. (They decay, rot, smell, things grow on them and insects buzz around them.)

Then ask students to suggest reasons for why this happens.

(Consumers, including decomposers, are changing them and getting energy from them.)

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Read the text. energy. Carnivores survive by eating animals that have eaten plants, animals or both.

Plants get solar energy directly from the sun. They use this solar energy to make the type of energy they need. They are called ‘producers’ because they produce or make energy themselves. They use sunlight, water, minerals and carbon dioxide to make energy. Producers store this energy in their tissues.

‘Decomposers’, such as bacteria and fungi, are another group of living things. Many of them are too small for us to see easily but they are very important to the flow of energy needed for life. These special consumers get energy from dead plants and animals by breaking down or decomposing, and changing them.

When they do this, they can produce material in the soil for plants to use.

The soil then becomes more fertile and plants grow better in it.

Omnivores get their energy from plants and all types of other animals.

The animals other animals eat have stored energy they haven’t used.

r o e t s Bocarnivores and r e Herbivores, p onot producers; they omnivores, arek u S are called ‘consumers’. They consume or eat other life forms.

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Almost all living things get their energy from the sun. Without the sun, the Earth would be a cold, dark place where there wouldn’t be any life as we know it.

This is because plants and animals must have some form of the sun’s energy to live and grow.

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Animals can’t make their own energy directly from the sun. To get the energy they must have, animals need to eat other life forms.

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o c Most living things get their energy . c e directly or indirectly from the sun. But her r • Herbivores eat only plants. o t sare some very rare, strange supe there r • Carnivores eat animals. and really interesting life forms • Omnivores eat both plants and animals.

These animals get their energy indirectly from the sun. Their energy must move from one organism to another.

that live deep in the oceans where there is no sunlight. These most unusual creatures get their energy from underwater hot springs, called ‘smokers’. There are chemicals made from sulfur in the smokers that provide these life forms with the heat energy they need to survive.

Herbivores survive by eating plants that have made and stored their R.I.C. Publications®

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Biological sciences

How do living things get energy to live? – 1

How do living things get energy to live? – 2 1. (a) Explain how plants get the energy they need to live.

3. Could all animals survive on Earth without herbivores?

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r o e t s Bo r e (b) What are these plants called? p ok u 2. Explain how animals Sget energy from the sun.

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Yes

No

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Why/Why not?

4. Give two examples of living things that get energy: (a) directly from the sun.

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(b) indirectly from the sun.

5. Explain how some decomposers help producers.

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Use the text on page 19 to complete the following.

o c . e 6. Compare and contrastc decomposers and other consumers. her r o t s super They are similar because They are different because 7. (a) Are bacteria decomposers? (b) Can you see them?

Yes

No

Yes

No

Why/Why not?

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1. You will need: Goal: To design and conduct an experiment to find factors that affect rotting.

• a clean, glassyou jar think (or plastic drink bottle withmore the top off) Prediction: (What causes things to rot andcut why.)

• a shoebox with the lid taped (like a hinged door) and holes poked in the end • soil (What will you need?)

Materials: • •2 sand plastic bags of food • water

r o e t •s refrigerator B r e oo • worms (What steps Procedures: will you take?) p u k onion • food scraps Ssuch as bits of potato and

2. Follow the steps:

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leaves • •marker

(a) Fill the jar with layers of soil and sand.

Observations and data: (b) Place the leaves, potato and onion pieces on top.

Material being tested: (c) Place the jar inside the shoebox and tape door shut.

What thing will you change in one sample? heat/water/air (d) Place in a cool, dry, dark place outside for a few days.

Date Observations Date Observations 3. Predict what will happen inside the jar. (a)

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Yes

No

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Why?

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o c . che e r o t r sin the jar? sup (c) What do you think will happen to the layers er

(b) What do you worms will do inside the jar?

Results: What doesthink yourthe data tell you?

(What caused rotting?)

Conclusion: (Compare your prediction with your results.)

4. Colour the correct word.

easy to make a worm habitat.

It was hard Evaluation: (What would you change to make it a fairer test?)

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Biological sciences

What happens when plants are no longer living?

Why do living things in a habitat interact?

Adaptation and interdependence of living things within ecosystems

Inquiry skills focus:

Questioning and predicting Planning and conducting Processing and analysing data and information Communicating

− An analysis of the reason each species is involved in symbiosis is required.

The lessons • Pages 23 and 24 should be used together.

• Students may benefit from working on the research project with a partner.

Answers

r o e t s Bo r e p ok u S Page 24

Background information

• Symbiosis means ‘living together’ and sharing the same space. It refers only to interaction between different species. Symbiosis assists living things to adapt to conditions within an ecosystem and helps to achieve a balance. The removal of one living thing can destroy this balance and affect many other living things. One organism can be in a symbiotic relationship with more than one other species at the same time.

• There are a number of different forms of symbiosis but the three most common ones are: − Mutualism in which both organisms benefit from the relationship. Oxpecker birds and zebra is one example. The birds obtain food when they eat ticks on the zebra, while zebra gain an effective form of pest control and are also warned of approaching danger by the bird’s screeching. Spider crabs and algae is another example. The crabs provide a place for algae to live and grow and are camouflaged by the greenish brown growth on their backs. − Commensalism in which one organism benefits and the other is unaffected. Barnacles growing on the skin of whales is an example as is arctic fox following caribou. They find small mammals coming closer to the surface, after holes have been dug in the snow by caribou, searching for lichens. − Parasitism in which one species benefits and the other is harmed. Humans and the E coli bacteria is one example. Aphids on plants, tapeworms in cattle, pigs and humans, and liver fluke in elk are others.

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1. (a) They live in groups so they can help each other to do things such as get food, keep safe and reproduce. (b) Answers will be similar to: Elephants live in herds. Fish swim in schools. Birds fly in flocks.

2. (a) An ecosystem is made of living things interacting with each other and with the nonliving things that are there. (b) They do this to survive.

3. One species using another species to help it in some way 4. Answers will vary.

5. Answers may include: insects pollinating plants, spiders spinning webs in trees etc. Teacher check (b) and (c).

Science as a Human Endeavour question Nature and development of science Teacher check

• Interaction within an ecosystem between living things and with nonliving things is essential for survival. This includes the interaction among members of one species, interaction with other species and interaction with the environment.

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Species 1: Ladybugs Description and habitat Small red flying insects with black spots that live on plants Why the species is symbiotic They get food (aphids) from plants.

Species 2: Ostrich Description and habitat A large flightless bird that lives on grasslands Why the species is symbiotic Has poor hearing and smell but good sight. It warns of danger.

Helped ✔ Helped with protection ✔ Species 2: Plants Description and habitat Leafy plants often found in gardens

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• One useful website is <http://www.seaphotos.com/symbiosis.html>.

Preparation

Species 1: Zebra Description and habitat A striped mammal like a horse that lives on grasslands Why the species is symbiotic Has good hearing and smell and uses them to sense danger Helped ✔ Helped with protection ✔

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Content focus:

Helped ✔ by symbiosis Helped with food ✔

Species 1: Sea cucumbers Description and habitat Soft-bodied animals that look like thick worms and are found in the sea Why the species is symbiotic They carry crabs and shrimps around.

Not affected ✔ by symbiosis

• Make a large chart similar to the one on page 25 with only two different symbiotic species listed. Use the chart to model the process needed to complete it. The information required for each question is as follows: − A brief description of each species and its habitat. − An explanation of the interaction and why it considered to be symbiotic. − The terms mutualism, commensalism and parasitism have been replaced by ‘help’, ‘not affected’ and ‘harmed’.

Why the species is symbiotic They get rid of aphids when ladybugs eat them.

Helped ✔ by symbiosis Helped with pest control ✔

Species 2: Crabs and shrimp Description and habitat Crustaceans with hard outer shells that live in water Why the species is symbiotic They are protected and taken from place to place.

Helped ✔ by symbiosis Helped with protection ✔ and transport ✔

2. Teacher check AUSTRALIAN CURRICULUM SCIENCE

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Read the text.

No living thing survives on Earth completely by itself. Living things are all part of an ecosystem. An ecosystem includes all the living things interacting with each other and with the nonliving things that are there too. These living things in the ecosystem must cooperate and interact with each other and with the nonliving things so they can survive. But they need to compete with other living things for things they need too.

r o e t s Bo r e p ok u S Finding food and staying safe are not always easy. Many living things find it

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Some of the reasons living things interact in an ecosystem are to get food, for protection or safety, and for reproduction. Most of them live with their own species in groups for these reasons. We call some of these groups herds, packs, flocks and schools. helpful to live with, or near, other species and to use them in some way. When one species uses another in this way it is called ‘symbiosis’. There are different types of symbiosis.

• Sometimes, when one species uses another it can be helpful to both of them. Crocodiles and plover birds do this.

Crocodiles open their mouths to let plovers clean bits of food from their teeth. They don’t hurt the birds and the birds get a good meal. Large fish like snapper and sharks and cleaner fish like shrimp and angel fish also help each other. The cleaner fish eat the dead skin and bits of food off the larger fish at ‘cleaner stations’ in the ocean. Zebra can hear and smell well but can’t see well. They are often helped by ostriches that can see well but can’t hear or smell predators. They work well together.

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o c . cheare only helpful to one species • Other symbiotic relationship while the other e r o one isn’t affected in any way.

Spiders spin webs on trees. It helps them catch t r s s r u e p insects but makes no difference to the trees. Egrets follow cattle to eat the insects they stir up when walking. This makes no difference to the cattle.

• Some symbiotic relationships benefit one species and harm the other. Parasites like worms and ticks, which suck blood from other animals, are examples of this type of harmful relationship. Fungi, bacteria and viruses are other parasites which can cause illnesses and death in plants and animals.

Living things can interact in other ways too. Living things can provide shelter or be a means of transport for others. Animals play an important role in pollinating some plants.

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Biological sciences

Why do living things in a habitat interact? – 1

Why do living things in a habitat interact? – 2 1. (a) Explain why many species of animals live in groups.

(b) Give an example.

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2. (a) What is an ecosystem?

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(b) Why do living things need to interact with other living and nonliving things in an ecosystem?

3. What is symbiosis?

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4. Describe an example of symbiosis where two species help each other.

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Use the text on page 23 to complete the following.

5. (a) Give an example of a plant and animal species having a symbiotic relationship.

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o c . che e r o t r s s r u e p (b) Does this relationship help both species?

Yes No (c) Does this relationship harm one of the species?

Yes

No

Discuss the symbiotic relationship between humans and animals and how each group benefits or is harmed by the other.

Choose one animal to research. Present an oral report to the class about its symbiotic relationship with humans. You may like to work with a partner.

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1. Use the internet or other resources to research information about the symbiotic interaction between each of these pairs of living things.

Species 1:

Species 2:

Species 1:

Species 2:

Zebra

Ostrich

Ladybugs

Plants

Description and habitat

Why the species is symbiotic

Description and habitat

Description and habitat

Why the species is symbiotic

Why the species is symbiotic

Why the species is symbiotic

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Why the species is symbiotic

Species 2: Crabs and shrimp Description and habitat

Why the species is symbiotic

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Description and habitat

Species 1: Sea cucumbers Description and habitat

Helped Helped Helped © R. I .

C.Pub l i cat i o ns Helped Harmed Harmed Harmed Harmed Harmed Harmed Not affected Notr affected Not affected Not Not Not affected •f o r evi ew pur paffected oses oaffected nl y• by symbiosis by symbiosis by symbiosis by symbiosis by symbiosis by symbiosis

Helped with: food

Helped with: food

Helped with: food

Helped with: food

Helped with: food

Helped with: food

protection

protection

protection

protection

protection

protection

transport pest control

transport pest control

transport pest control

transport pest control

transport pest control

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transport pest control

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Helped

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Helped

o c .a report.

2. Chose two other symbiotic write chespecies to research andr e o r st super

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Biological sciences

Researching symbiosis

What are food chains?

Inquiry skills focus:

The lessons

Feeding relationships

• Pages 27 and 28 should be used together.

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

• Page 29 requires students to make and record some observations about living things in their local environment, such as within the school grounds, at a park, in and near a lake, in a garden or at a beach.

• Before students enter the area they intend to investigate, ask them what they think they will find there. They should look for living things they believe either eat or are eaten by each other. Encourage them to ask themselves two questions: ‘What eats this?’ and ‘What does this eat?’

r o e t s Bo r e p ok u S

• A food chain can be defined as ‘a community of organisms where each member is eaten in turn by another member’. Food chains can show energy flow through local ecosystems and the relationship between prey and predator. In a relationship an animal can be both a predator and prey of another animal.

• Students classify each living thing as a plant or an animal, record where they observed the living thing (its habitat), how many there were (few, some or a lot) and describe them (observation notes).

• Students then choose some living things from their observation list to write in Question 2. They are then required to decide for each of them, which of the other living things they have listed, is its prey and which is a predator that preys on it. They then choose one of these relationships to use as part of a food chain and draw it.

• Learning about food chains helps students to understand how living things are connected and how changes in the environment can affect large numbers of different living things. They need to understand that this means one human action can affect countless other organisms.

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• Ask students to reflect on how they carried out the investigation and suggest ways to improve it.

• The idea that there needs to be more of a species at the bottom of a food chain than at the top can be quite difficult for some students to understand. It may help them if the animals in the food chain are shown in a pyramid. lion For example:

Answers

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deer

• Food webs are a more realistic way of looking at the relationship and interdependence of living things. Involvement in numerous different food chains decreases an organism’s level of dependency on a particular living thing. The greater the number and complexity of food webs, the more chance an organism has of survival. Unfortunately for many of the Earth’s endangered species, this is not the case.

1. Food chains start with a plant and end with an animal.

2. There wouldn’t be enough food for the animals at the top of a food chain if it was very long.

3. They need to use some energy to live and grow and some goes to waste.

4. There’s not food for all of them, so some die.

5. They are not usually eaten by other animals.

6. (a) grass - sheep - human (b) wheat - chicken - fox (c) plankton - fish - seal - polar bear

• Some useful websites include:

Page 29

grass

• They also need to understand that animals need to use some of the energy they take in. As a result, it’s not all available to the animals higher up the chain.

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Content focus:

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− <http://www.ecokids.ca/pub/eco_info/topics/frogs/chain_ reaction/play_chainreaction.cfm>

Teacher check

− <http://www.education.com/reference/article/energy-flow-foodchain/>.

Preparation

• Remind students that there are different groups of living things including producers and consumers and that they get their energy from the sun. Producers make their food using energy from the sun, but consumers need to get their energy from producers or other consumers or from both. They may need to be reminded that herbivores, carnivores and omnivores are three groups of consumers and of what each group eats.

• Check that all students understand the meaning of the words ‘predator’ and ‘prey’.

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Read the text.

Living things must use energy from the sun to live and move. Animals get their energy from the food they eat. When they eat, the energy they need is released from their food when they digest it.

r o e t s Bo r e p ok u S

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Plants and animals are parts of food chains. A food chain explains how each of the living things in the chain gets its food. So you could say that a food chain shows ‘who is eating whom’. All food chains start with a plant and end with an animal. Each link in a chain is food for the next link. This is how energy is passed from one link to the next. Humans, other large mammals and birds without natural predators are often the last link in a food chain.

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C.Pu l i cat i on It b is important that as food chain is kept in balance. If there are too many of one •f orr evi ew pu r po ses obe nl y•food species, there won’t enough

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for them and some of them will die. If something happens to a species and there aren’t enough of them left, the animals that need to eat them could die. If this happens it would also affect any other animals further up the food chain and they could die too.

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Most food chains have three or four links. If there were too many links in a food chain, there wouldn’t be enough energy left for the last link in the chain to use. This is because when one link in the food chain gets its energy, it uses some of it to live and move, some of it goes to waste and it can only store the energy that’s left over in its body. Then this stored energy is the only energy the next link in the chain can use.

o c . che e r o t r s Because an animal only stores s uper part of the energy it gets in its body, there needs to be a greater number of the species in the first links of the food chain than in the last links. If there weren’t more of them in the first links, there wouldn’t be enough energy left for the last links and they couldn’t survive.

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But a disaster like this doesn’t always happen because many species belong to more than one food chain. This protects them when there’s a problem with one food chain. Food chains that are linked to other food chains are called food webs. Species who belong to them are more likely to be able to survive changes in their ecosystem.

Omnivores are the most likely animals to survive ecological changes, because they belong to lots of different food chains and have more food choices.

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Biological sciences

What are food chains? – 1

What are food chains? – 2 1. Food chains start with a

and end with an .

2. Why aren’t food chains very long?

r o e t s Bo r e p ok u 3. Why can’t animalsS pass on all the energy they get from their food?

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4. What happens if there are too many of the animals in one link of a food chain?

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5. Why are humans often the last link in a food chain?

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6. Complete a food chain showing each group of living things.

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(a) human, grass, sheep

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Use the text on page 27 to complete the following.

o c . che e r o t r s super (b) chicken, fox, wheat (c) fish, plankton, polar bear, seal

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Local environment studied:

Date:

1. Find and observe living things that could be part of the same food chain and write information about each of them in the chart below.

Plant/ Animal

Habitat

Observation notes

Rare/Some/Many

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Name

Number observed:

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2. (a) Write the names of some living things from the chart that are part of the same food chain.

.

Prey of: Predator of: te o Living thing: c Prey of: Predator of: . c e r Living thing: h er Prey of: o st Predator of: super Living thing:

Living thing:

Prey of:

Predator of:

(b) Draw a food chain which includes at least two of these living things.

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Biological sciences

Observational report

Why are living things endangered?

Content focus:

Inquiry skills focus:

• With assistance, students work out how to present their completed report to the class or small group.

Nature and development of science

Endangered animals and plants include: giant panda, tiger, hairy-nosed wombat, bilby, African elephant, blue whale,Tasmanian devil, green sea turtle, baobab tree, green pitcher plant and the monkey puzzle tree.

Scientific research about endangered or extinct living things Questioning and predicting Planning and conducting Processing and analysing data and information Communicating

Background information

Teac he r

r o e t s Bo r e p ok u S Answers

Page 32

1. (a) in danger of becoming extinct (b) has died out—none left living 2. (a) Because the world’s population has grown, more habitats are being destroyed for farmland, roads, houses and other buildings. (b) Plant destruction removes the shelter and protection from predators of many animals. (c) When animals’ homes are destroyed when land is cleared, they have to try to find another place to live.

3. They are hunted for their meat, body parts, fur or skins, or to become pets.

4. Rabbits take over bilbies’ burrows and eat their food.

5. Answers may include: Nests for birds and insects, shelter for spiders’ webs, insects’ cocoons and eggs, protection for animals’ burrows etc.

6. They use the information to help them find food and to know when it’s the best time to hunt them so the species are preserved.

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• In the past, the survival of livings things was affected by natural changes, such as the Ice Age. Today, species are more likely to be affected by changes in their environment and loss of habitat caused by human action.

• Environmental science studies have discovered ways in which human activities can weaken an environment’s life-support system, leaving living things within it vulnerable. Today, around 5500 animal species and as many as half the Earth’s plant species are known to be threatened with extinction.

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• The World Conservation Union has status categories for threatened plants and animals. Refer to: − <http://www.kidskonnect.com/subject-index/13-animals/29engangered-animals.html>.

Page 33

• Some useful websites include:

Teacher check

− <http://www.sheppardsoftware.com/content/animals/ kidscorner/endangered_animals/endangered_game.htm> (Game that identifies why specific animals are endangered)

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Science as a Human Endeavour unit:

− <http://www.kidcyber.com.au/topics/austendangered.htm> (List of some Australian endangered animals)

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− <http://www.kidsplanet.org/factsheets/map.html> (List of endangered species worldwide) Preparation

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• Research reference books or the internet for pictures of endangered animals and plants for students to view.

The lessons • Pages 31 and 32 should be used together.

• Students could work individually or in pairs to complete the report on page 33. They could choose from the list of endangered species below, refer to some of the websites listed above or carry out other research to find their own endangered living thing. Additional questions students could ask, to fill in the blank box provided on page 33, include: ‘What can be done to help it survive?’ and ‘What is another interesting fact?’

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Why are living things endangered? – 1 Biological sciences

Read the text.

Humans share the Earth with many other living things.

Unfortunately, some of the things people do have caused many of those living things to become endangered: that is, in danger of becoming extinct or dying out.

Plants and animals may be endangered for many reasons, including:

Teac he r

grows, more and more land is cleared and plants are destroyed to make way for farming, roads and buildings. The trees and other plants removed may have provided shelter and protection from predators for many different animals, including birds and insects and their nests, spiders and their webs and rabbits and their burrows. Animals like these are ‘pushed out’ of their natural habitat.

Finding somewhere else to live and the food they need is often too difficult and many animals can not survive.

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r o e t s B r e o Destruction of habitat Introduced p ok species u Introduced animals and plants This is the biggestS problem for the world’s are those not native to an plants and animals. As the Earth’s population area. They have been brought there for a particular purpose from other habitats, often in different countries. Many introduced animals thrive in their new habitat. They reproduce successfully, then large numbers of them compete with native animals for the food and shelter they need. Foxes, rats, rabbits, camels, cats and goats are examples of species that have been introduced into Australia. Similarly, introduced plants can grow extremely well in their new habitat. They often spread, blocking the native flora’s sunlight and using up the soil’s nutrients.

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Hunting

Aboriginals and Torres Strait Islanders, like other hunters in the past, collected information by observing and investigating patterns of animal behaviour in a scientific way. They, for example, used information about turtle nesting and other animal behaviour to find food they needed, but they were careful about preserving the species they depended on.

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o c . che e r o Pollution t r sAir, water and soil pollution super

Sadly, today many animals are hunted illegally for their meat, body parts (e.g. tusks), fur or skins, or collected as exotic pets. Fish species are endangered because fishermen ignore the rules about how many fish they can take, what size they have to be and when and where they’re allowed to fish. This affects fish’s breeding cycles and reduces their numbers.

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caused by chemicals, fertilisers, factory wastes and oil spills can kill animals and plants. Pollution is an increasing problem. Many of the world’s scientists are researching and collecting information to help them find ways of reducing it.

AUSTRALIAN CURRICULUM SCIENCE

Why are living things endangered? – 2 1. What is the meaning of each of these words? (a) endangered (b) extinct 2. (a) Why are so many animal and plant habitats being destroyed?

(c) What must animals do when their habitat is destroyed?

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r o e t s Bo r e p ok u (b) How does plant destruction affect animals?

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3. Why are animals hunted?

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4. The rabbit and the bilby are similar creatures.

The rabbit is a major cause of the bilby becoming endangered. Explain two reasons for this.

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Use the text on page 31 to complete the following.

o c . che e r o t r s for animals? up er 5. What are some of the ways a trees can provide shelter

6. How do Aboriginals and Torres Strait Islanders use information about animals and plants they have collected over many years?

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1. (a) Choose an endangered animal or plant to plan a report about. (b) Make notes next to each question below. (c) Add one question of your own in the blank box and make notes.

Name

Where is it found?

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What does it look like?

How has its habitat changed?

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What drawings or diagrams will I need?

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What websites, books etc. will I need?

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endangered?

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2. Prepare your report and present it to the class.

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Biological sciences

Endangered living thing report

What properties do materials have?

Content focus: Inquiry skills focus:

Answers

Properties of different materials

Page 35

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

r o e t s Bo r e p ok u S

Teac he r

• Properties of materials are those characteristics that determine their suitability for specific applications. This knowledge helps in recognising what needs to be considered when a material is chosen for a particular use.

• One useful website is <http://www.teachingvideos.co.uk/index. php/videos/viewvideo/229/materials/materials-video> (short video about properties of different materials).

Preparation

Page 37

• Collect some of the examples of the materials in the table on page 35 for students to examine and test for the property described.

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Teacher check Note: When students test their materials, they may find that some test better for that property than others; e.g. coffee crystals were more soluble than oil. Their explanations in the ‘Results’ column should reflect this.

• Organise equipment needed for the investigation on page 37. Examples of materials for students to choose to test for different properties could include: elastic bands, paper clips, paper (tissue, cellophane, wrapping paper, newspaper, file paper, paper towel), cardboard, rubber balls, plastic (cling film, plastic shopping bags, resealable bags), cloth material (felt, silk, cotton, denim, nylon stocking, polyester, towelling, wool, lycra), leather, cottonwool, pebbles and rocks, glass, wood, mirrors, sponge, balloons, aluminium foil, sugar, cooking oil, salt, flour, sand, modelling clay, chalk, ribbon, rope, metal (from empty tins of food). Other equipment such as scissors, rubber mallets, torches and tape measures will be needed, according to how students decide to test for specific properties.

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1. (a) False (b) True (c) False 2. Different materials can have different properties because their molecules and atoms are arranged differently.

3. transparent and opaque 4. (a) plastic (b) sponge or paper towel (c) clear glass 5. They are both able to be stretched.

6. Answer should indicate gold can be worked into different shapes required in jewellery for making rings, bracelets, chains and so on.

7. Possible answers: (a) absorbent (b) waterproof (c) flexible (d) hard 8. Answer should indicate glass is brittle so care is needed so they don’t break during stacking.

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• Students could work with a partner or in a small group for the investigation on page 37. Teacher chooses a different property for each pair/group to test for. Properties could include those listed on page 35 or others such as softness or the ability to float or sink. As a group/pair, students decide on four materials to test, considering what would not be a suitable or a safe choice; e.g. glass would not be a safe choice to test for flexibility. They work out the same test for each material so the test is fair; e.g. mix one teaspoon of each substance with 200 mL of water, stirring 10 times. They predict the outcome before testing. If all in the group don’t agree with the prediction, students should write their name and prediction separately in the table.

• Discuss any problems the students had in planning and carrying out their investigation. Reflect on the methods used in testing procedures etc.

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What properties do materials have? – 1 Read the text.

Natural and synthetic (made using chemicals) materials have properties and characteristics that distinguish them from other materials. These properties can be detected using our senses. For example, one way to tell the difference between rubber and wood is we can see and feel that rubber stretches because it’s elastic, but wood doesn’t because it’s rigid.

r o e t s Bo r e p of materials, explains each ok The table below listsu properties term and gives examples of materials with that property. Some of the examples are S actual materials and others are objects made from materials.

Transparent Translucent

Explanation

Examples

allows light to pass through so we can see objects clearly through it allows some light to pass through but we cannot see objects clearly through it allows no light through so we cannot see anything through it

clear glass, clear plastic tissue paper, frosted glass

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C.Publ i cat i ons brick, wood sponge, paper •f or r e i ew pu r p os sonl y • Absorbent able tov soak up water and other fle uids towel

Waterproof

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Hard

prevents water and other fluids from penetrating solid and firm to touch, resists changing shape when pressure applied able to be worked into a different shape by hammering or rolling able to be bent or stretched without breaking able to return to its original shape when a force is removed

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Malleable

plastic, glass

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Opaque

wood, rock copper, gold

Magnetic

wool, leather o c . che rubber band, e r balloon o r st super iron filings, attracted to a magnet

Reflective

able to give off a reflection

Flexible Elastic

paperclips mirror, aluminium foil

Soluble

able to dissolve in a liquid such as water

sugar, salt

Rough

having a coarse surface

sandpaper, brick

Brittle

easily broken

china, glass

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Chemical sciences

Property description

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Materials are made up of molecules and atoms, too small to be seen without an electron microscope. How these are arranged determines the properties of a material.

What properties do materials have? – 2 Use the text on page 35 to complete the following.

1. Circle true or false. (a) Only natural materials have properties.

True

False

(b) Materials can have more than one property.

True

False

(c) Rubber and wood are both rigid.

True

False

r o e t s Bo r e p ok u S

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3. Circle the two properties that are opposite. transparent

translucent

opaque

4. Which material(s) listed would be best to use if you wanted to: (a) make a raincoat?

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(b) mop up some spilt water? (c)

5. What is similar between a material that is flexible and one that is elastic?

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6. Why is gold one of the metals used in jewellery making?

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2. Why do different materials have different properties?

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7. Describe one property each of these objects should have. (a) bath mat

(b) umbrella

(c) hammock

(d) door

8. Why do we need to be careful when stacking glasses in a dishwasher?

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Testing! Testing! 1, 2, 3, 4!

Property to test:

r o e t s Bo r e p ok u S

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How will you choose your materials?

How will you test for this property?

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. t Results for e each material:

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Prediction for each material:

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Improvements to the investigation:

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Chemical sciences

Materials:

Why search for new materials?

The lessons

Science as a Human Nature and development Endeavour unit: of science/Use and influence of science Content focus:

• Explain that when bicycles were first made, cycling was not as leisurely as it can be today. It has been the continuing development of design and materials that have led to the superior quality of machines that exist today.

Finding materials with properties to match changes in design and specification

• For the investigation on page 41, divide students into groups and give each group a supply of one type of thread; for example, wool, packing string, garden twine, fishing wire, raffia etc. Students construct paper trays using the templates and carefully insert two satay sticks at right-angles to each other as shown in the diagram.

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

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Each group suspends one paper tray from a hook using a length of thread. They add units of weight, counting one at a time until the thread breaks. In the table, students record how many units it took to break the thread. This number of units must now be weighed to give a standard weight in grams.

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• The frame is the most important component of a bicycle because its quality can affect the performance of the machine.

If students have a very strong thread, they may have to choose heavier units of weight.

• Mass produced frames are built with a material to give good quality for a reasonable cost making them affordable to a wider market.

Students now find ways to strengthen the thread; for example, plaiting three strands together, crocheting it, tying knots at intervals along its length etc. They test each length of thread to determine the most effective method of strengthening.

• Hand built frames are made using the best materials the clients can afford, meeting specific requirements of stiffness, strength and weight.

Students must consider fair testing. Does the length of thread being tested, or the method of attachment to the hook and tray make a difference? How could they test this?

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• Stiffness refers to how much a material will flex under weight before returning to its original shape after the weight is removed. Stiffness affects the riding quality of the frame. All steel types have the same stiffness.

Answers

• Strength refers to how much weight a material can support before yielding—reaching the point beyond which it cannot return to its original shape. Strength affects the durability of the frame. Frame strength is governed by the quality and alloying elements used in different frame tubing.

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1. to maintain the shape of the frame under the rider’s weight 2. (a) iron (b) less carbon gives a more flexible frame 3. flexibility: frame will not break completely on impact; shock absorption: rider has more comfortable ride because impact of bumps and ruts in road is absorbed by the frame 4. (a) strong, rigid (kept its shape) (b) strong, heavy, brittle (c) strong, heavy, flexible, shock absorbent (d) strong, light, flexible 5. Teacher check. Possible answers include: less pollution, fewer materials needed, easier waste management etc.

6. Using nanotechnology, carbon fibre frames weighing under one kilogram have been built.

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Inquiry skills focus:

• Pages 39 and 40 should be used together.

• Material quality is linked to frame design. Manufacturers choose the optimum diameter and wall thickness of frame tubing to make the best use of the material. The wider the diameter, the stiffer the frame.

The thicker the walls, the stronger the frame. A wide diameter and thick walled tubing will produce a heavier frame than a narrower, thin walled tubing.

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• One useful website is <http://www.pedalinghistory.com/PHhistory. html>.

Preparation

Page 41

• Students bring in their bicycles to compare tubing diameter and overall weight.

Teacher check

• Make a collection of coloured pictures of bicycles from different eras.

• For the activity on page 41, copy paper tray templates, one per student, from <http://rubberstamping.about.com/od/templates/ss/ folded-paper-tray-template_4.htm>. Students will also need satay sticks and a supply of different kinds of thread.

Students need access to hooks, maths equipment that can be used as units of weight (for example, marbles, wooden or plastic blocks) and weighing scales.

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Why search for new materials? – 1 Read the text.

The word ‘material’ means what something is made from. When choosing a material for a job, it is important to use one that can do the job well.

Even when a suitable material is found, inventors, scientists and engineers continue to search for new ones that will perform even better.

Look at the history of bicycle frame building.

r o e t s Bo r e p o u As the design of the bicycle improved, frames were madek S iron is an alloy of iron. This means that from cast iron. Cast Cast iron was an improvement on wood but it was still heavy. The amount of carbon made the frame very brittle. In a collision, frames could break suddenly and completely.

Another iron alloy, wrought iron, was the next material to be used. Although still strong and heavy, wrought iron contained very little carbon. This made the frame more flexible and less likely to break on impact. Instead, after a number of collisions, the frame showed signs of ‘wear and tear’, warning the owner that it might not last much longer.

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Riding a bicycle with a wrought iron frame made a journey more comfortable because wrought iron absorbed shock much better than wood or cast iron. This was important in the days before the motor car when roads were very rough.

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As bicycle designs and road surfaces improved, properties of materials needed for frames changed. They had to be lighter and more flexible so frames had a little ‘give’ in them, weren’t easily damaged and allowed the rider to ride faster.

o c . c e r By the end of the 19thh century, most frames were made e o t r s su er pmade from steel tubing, not solid metal.

This the frames much lighter while still being strong. Steel is also an alloy of iron. It contains some carbon and other materials too.

Bicycles are still made with steel tube frames but serious cyclists want even lighter machines. Alloys of aluminium, titanium and magnesium metals are used to make super light, strong frames. Another change is the increasing use of different types of plastic for features such as the seat and handle grips.

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it is mixed with another element, in this case, carbon.

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The first bicycles were made almost 200 years ago.

Wood was used for the frame as it was strong enough to take a person’s weight and keep its shape.

Why search for new materials? – 2 Use the text on page 39 to complete the following.

1. Why does a material used for building bicycle frames have to be strong?

2. (a) Which metal has been the main part of materials used for building

r o e t s Bo r e p o u k flexibility?

S 3. Which two properties of a wrought iron frame would make it more popular than bicycle frames?

a cast iron frame?

Property

Reason for popularity

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4. Complete the table by writing the properties mentioned in the text of each material.

(a) wood

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(b) How does the amount of carbon added to the metal affect a frame’s

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(b) cast iron

(c) wrought iron

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6. Research on the internet to see if you can find out whether the statement is true or false.

Bicycle manufacturers have built a frame weighing less than one kilogram.

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Can you make a material stronger?

Can changing how a material is used in construction improve its properties?

1. (a) Carry out an investigation to find out: – how much weight a length of thread can support before it breaks – how the thread can be changed to support a greater weight – the greatest weight the thread can support.

You will need:

r o e t s • paper trays madeB from templates r e oo • a hook p u k S • weighing scale

(c) Record your results in the table.

2. Which do you think will hold the greatest weight?

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(b) Set up your equipment as shown in the diagram.

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• a supply of thread • satay sticks • units of weight

Units used:

Type of thread:

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Weight of units (g)

How thread strengthened

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How thread strengthened How thread strengthened

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(b) Why do you think this was?

4. (a) How would you rate your investigation?

Poor

Good

(b) What could you do to improve your investigation?

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What is insulation?

Content focus: Inquiry skills focus:

• For the activity on page 45, discuss the types of materials students could test. To make the test fair, how much of the material should be used? Will it make a difference? If something like dried leaves is used, how will they be contained? If a light bag is made to hold them, how might this affect the results? If small pieces of some materials are used, they may hold trapped air which would affect the result. How might these problems be overcome?

How insulation works Questioning and predicting Planning and conducting Processing and analysing data and information Communicating Evaluating

Procedure:

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• Cut up test materials into similar sized pieces.

Background information

• Staple two pieces of cloth around the edge to make a ‘pillow’, leaving a hole to add a known quantity, by volume, of material. Then staple this hole. One pillow, the control, must be made with no filling.

Teac he r

• Set required number of polystyrene cups plus one extra, in a row.

• Mark each cup at 2/3 level.

• Carefully pour hot (tap or partially boiled) water to the mark of each cup and cover immediately with insulating pillow. Cover the extra cup, the control, with the empty pillow.

• Some useful websites include:

− <http://www.kids-science-experiments.com/ heatconductorsandinsulators.html>

• Record the temperature of the water in the control cup. This is the starting temperature.

− <http://www.sciencekids.co.nz/gamesactivities/keepingwarm. html>.

• At ten minute intervals, quickly but carefully, remove the pillow from each sample, stir the contents and record the water temperature then replace the pillow. Always record in the same order so that the time difference is the same.

• The word ‘thermal’ relates to ‘heat’.

Preparation

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• Collect coloured pictures and advertisements of energy efficient methods of reducing heat loss from the home. Bring in examples of insulated bags and cooler bags and boxes. If possible, pull apart and examine the insulating materials.

Answers

Page 44

1. (a) conductors (b) insulators 2. insulating the roof space and cavity walls and installing double glazing 3. Insulation keeps buildings cooler in summer and warmer in winter.

This reduces energy requirements so less fossil fuels need to be burned to produce the energy.

4. to stop heat transfer between the air inside and outside the bag or box 5. (a) The person wearing the clothes has to carry the insulation as well. (b) an insulator that traps air because it would be light and less dense so more effective than one that did not 6. (a) Metal is a good conductor. It will transfer heat from the liquid inside the kettle or from your hand—so it feels cold when it is filled with cold water and hot when the water inside the kettle has boiled. (b) A plastic kettle would keep water hotter for longer because it is a better insulator, or poorer conductor, than metal.

7. Teacher check. Possible answer: Many of these materials cause pollution when they are burnt or disposed of in landfill.

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• Pages 43 and 44 should be used together.

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• For the activity on page 45, provide a range of materials for students to test; for example, wood chips, cotton wool, aluminium foil, rubber, plastic, wool, cotton. Cut out enough cloth circles for students to make ‘pillows’ for their test materials. The cloth used should be light, but able to contain the pieces of material; for example, muslin or an old pillow cover. The pillows must be large enough to sit on the polystyrene cups but not so big that they will unbalance them.

They can be stapled around the edges after the students have cut and weighed the materials.

The lessons

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• Heat energy can be transferred in three ways; radiation, which can be sensed by the skin; convection, which transfers through the movement of fluids (gas or liquid); and conduction, which moves from warmer areas to cooler. Thermal insulation means resistance to the flow of heat energy.

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• Discuss the effect of air temperature on the temperature of students’ homes. What steps do they take to minimise this? For example, do they close windows, blinds and curtains during the day in summer and open them at night? They may reverse the process in winter. Or they may insulate ceilings, install ceiling and rooftop ventilators, and turn on cooling or heating.

• Discuss the long-term environmental and financial advantages of insulating the home properly – reduced energy requirements and cost.

Page 45 Teacher check

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What is insulation? – 1 Read the text.

Insulation is a barrier that stops heat energy from moving to a cooler place. Many materials can be used for insulation; for example, air, cork, polystyrene, fibreglass and paper.

Insulators and conductors are opposites. Conductors allow heat energy to pass through them. Metals are examples of good conductors.

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Teac he r

r o e t s Bo r e p o u k of the materials Less dense materials are better Getting rid of some S thermal insulators, so gases are better used for insulation is a problem when than liquids, which are better than solids. Some of the best insulators trap air, just as feathers, fur and hair do, to keep body heat from escaping.

pulling down older buildings. Most of this material goes to landfill and some is burnt, but it is a growing challenge and many local councils are trying to find ways of recycling some of it. Polystyrene, for example, can be recycled to make decking or outdoor furniture, but transporting it to special recycling centres is expensive.

Disposing of some of the insulating materials, such as asbestos and fibreglass, can be dangerous. Even safer materials used for insulation collect lots of dust over many years and working with these materials can be a serious health hazard for workers.

The roof space and wall cavities in buildings can be insulated to reduce heat transfer.‘Double glazing’ is a sealed unit of two panes of glass with a layer of air trapped between them. This is a very effective method of reducing heat transfer through windows. If a building is well-insulated, it will be cooler in summer and warmer in winter. This means energy costs will be much lower and that’s good news for the planet!

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It is not just buildings that need insulation. When you have a picnic on a hot summer day, how do you store your food? Cooler bags and boxes with lids have a layer of insulation that reduces heat transfer between the air inside and out. Adding ice blocks lowers the inside temperature, keeping food cooler for longer. Vacuum flasks and travel mugs are also insulated containers, keeping drinks hot or cold.

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Clothes are designed using knowledge of insulating materials. Thermal jackets and trousers worn by people in very cold places are padded with light but effective insulation. This keeps body heat in and cold air out. In warmer places, the clothing worn is designed to allow air to flow and to ensure that body heat isn’t trapped inside.

What is insulation? – 2 Use the text on page 43 to complete the following.

1. Place the words in the correct sentences.

insulators

conductors

(a) Materials that allow heat transfer are called

.

(b) Materials that reduce heat transfer are called

.

2. Heat transfer between the inside and the outside of buildings can be reduced by:

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4. Why do cooler bags and boxes need lids?

.

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5. (a) Why does insulation used in cold weather clothing need to be light?

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(b) What type of insulator do you think would be very effective for cold weather clothing? Give a reason for your answer.

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r o e t s Bo r e p ok u 3. How can insulatingS buildings be good for the planet?

6. (a) Why does a metal kettle feel cold when you fill it and with cold water and hot when the water has boiled?

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o c . che e r o t r s skeep r pe (b) Would a metal or a plastic kettleu water hotter for longer? Explain.

7. How could some insulation materials cause pollution?

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The best thermal insulators and conductors Thermal insulators are materials that help to maintain a temperature by keeping heat in or out. Thermal conductors allow heat to pass easily through them, creating a noticeable rise or fall in temperature.

1. (a) Plan an investigation to test different materials and determine whether they are good thermal insulators or conductors.

You will need: • material for making ‘pillows’ • stapler • weighing scales • materials for testing • polystyrene cups • hot water • thermometer • stirrer • clock

2. Which material do you think will be the best insulator?

conductor?

3. Results

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(c) Record your results in the table.

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r o e t s Bo r e p oas your teacher tells (b) Prepare youru materials and set up the investigationk S you.

Rank best Temperature after: © R .

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P u b l i c a t i o n s 10 min. 20 min. 30 min. 40 min. 50 min. 60 min.

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Starting temperature (°C)

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Material

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5. What steps did you take to ensure you carried out a fair test?

6. What could you do to improve your investigation?

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. .

What are materials scientists?

Science as a Human Endeavour unit:

Content focus:

Nature and development of science/Use and influence of science

Page 48

Questioning and predicting Planning and conducting Processing and analysing data and information Communicating

Background information

r o e t s Bo r e p ok u S

• Materials science involves biology, chemistry, physics and engineering. Rapid progress in materials science has occurred as the result of advanced technology combined with creative and imaginative thinking ‘outside the square’.

• To date, there are about 300 000 natural or synthetic materials in use. The number will continue to increase as materials scientists discover new ways to create and combine materials.

Page 49 Teacher check

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• Some useful websites include:

− <http://www.strangematterexhibit.com/whatis.html> (Although American, this website provides a comprehensive coverage of all aspects of materials science and is targeted towards middle to upper primary school students.)

− <http://www.pbs.org/wgbh/nova/tech/materials-changed-history. html> (History of 10 resources and their impact on society) − <http://www.inventor-strategies.com/index.html> (Information about new inventions)

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1. He or she studies how materials are structured or put together.

2. (a) unique (b) molecules, atoms (c) properties, molecules, atoms (d) existing, create 3. (a) gold/tin/copper (b) pottery/alumina/zirconia (c) silicon/copper (d) paint/plastic (e) fibreglass (f) artificial bone 4. (a) Biomaterials are synthetic. (b) A composite material is made up of different combinations of materials.

5. (a) metallurgists (b) Possible answers: work with more than just metals/use technology to help them/ study the molecules and atoms that make up materials/don’t just work by trial and error

Work of materials scientists

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Inquiry skills focus:

Answers

Preparation

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• Suitable classroom objects made from different materials can be used for students to identify their origin, either natural or synthetic, and what materials they are made from.

The lessons

• Pages 47 and 48 should be used together.

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• Students can work individually or with a partner to complete the report on page 49. The teacher could suggest, or the students could choose, devices or materials to research. These include electronic ink, steel, kevlar, biodegradable plastic bags, titanium, electronic computer chips, fibre optics, lasers, DVDs, plasma TV, insect robots, aerogels, pneumatic tyres, hybrid cars, needle-less injections, retinal implants for the blind, self-cleaning clothing and tissue regeneration.

• If necessary, guide students to decide on research headings in Question 2 on page 49. They should include, for example, research into what it does; how it works; who developed it; what benefits, advantages and disadvantages it has; and the origin of its name.

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What are materials scientists? – 1 Read the text.

r o e t s Bo r e p ok u S

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These scientists investigate the structure of materials by examining their chemical and physical properties. Every material has a unique structure made up of molecules and atoms which are visible with an electron microscope. How these are arranged determines a material’s properties; e.g. its strength, elasticity or absorbency. Materials scientists use this information to improve existing materials and to create new materials for specific purposes. For example, banknotes were once made from paper. They tore and creased easily and were easy to counterfeit (make fake copies). Materials scientists developed a product made from polymer, a type of plastic. This made banknotes much more durable and very difficult to copy.

Materials science began centuries ago when people worked out how they could change metals. They discovered that mixing copper and tin together produced bronze, which is much stronger than pure copper. These people who worked with metals were known as ‘metallurgists’, from a Greek word meaning ‘mine worker’.

Modern materials scientists do more than just change or work metals like gold or tin. Some of the other categories of materials they study include:

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C.Publ i cat i ons •f orr ev i ew pu r pos esand on l y• Ceramics: Traditional ceramic Polymers: Paint plastic are

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materials made from polymers. They are materials, classified as pottery, made up of long chains of molecules are made from clay or a similar material. Modern-day, advanced joined together in different ways. ceramic materials are often made Composites: Materials composed from materials such as alumina and of different combinations; e.g. glass zirconia. They go through a special fibres and plastic form fibreglass. process and form much harder and more durable products than traditional Biomaterials: Synthetic materials with similar properties to living things; ceramics. They can be used in other e.g. artificial bone. ways; e.g. as cutting tools.

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o c . che e r o t r selectricity; e.g. silicon, copper. su r pe(carry) Semiconductors: Materials that conduct

Materials scientists tend to specialise in a particular area. They usually work with one kind of material, such as metals or fabrics. In the past, new materials were made by trial and error. Advances in technology have changed the way materials scientists work. They can use computer models to test ideas first before making something and testing it in the ‘real’ world.

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A material called ‘kevlar’ is used in bullet-resistant vests and bicycle frames.

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As the name suggests, materials scientists work with materials.

Practically everything you use each day—your bed, toothbrush, car, computer and DVDs—are all made from different materials. Materials scientists are particularly interested in how materials are structured or put together.

What are materials scientists? – 2 Use the text on page 47 to complete the following.

1. Explain what a materials scientist studies.

2. Use a word or phrase from the text to complete these sentences. structure. r o e t s Bo r e (b) Materials are made p up of ok u .

Sand (c) The

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a material has are

determined by the arrangement of its and

.

(d) Materials scientists improve

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C.Publ i cat i ons Give an example of a material next to each of these categories• thatf materials o rr escientists vi ewstudy. pur posesonl y• materials and

3.

new materials.

(a) metals

(b) ceramics

(c) semiconductors

(d) polymers

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(e) composites

(f) biomaterials

4. Correct the error in each sentence. Rewrite it correctly.

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(a) Every material has a

o c . che e r o (b) A composite material is made from one substance. t r s super (a) Biomaterials occur naturally.

5. (a) In the past, materials scientists were called

.

(b) Describe one way modern materials scientists’ jobs differ from those of the past.

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Inventions and devices research Materials scientists have created and are continuing to make improvements to existing materials and creating new materials. Some of these are natural materials (e.g. paper) and others are synthetic (e.g. plastic).

These discoveries have led to many devices and materials being invented and developed. Examples include baking paper and ‘rubber’ cake tins for use in ovens and biodegradable plastic bags.

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r o e t s Bo r 1. What device are you e going to research? p ok u S

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2. What headings will you use to guide your research? These should tell you what you already know and what you need to find out about this device.

(Make brief bullet point notes under each heading to expand your research.)

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3. What reference sources will you use?

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o c . che e r o t r swill you include? s 4. What diagrams, illustrations or photographs u per 5. How will you present your report?

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Choose an existing device or one being developed to research and write a report to share with your class. Use the questions below as a guide to plan your report.

What is weathering?

Content focus: Inquiry skills focus:

• Encourage students to bring in examples of rocks that have been weathered by water and discuss how and where this may have occurred.

Causes of physical, chemical and biological weathering Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

• To demonstrate the effect of heating and cooling on rock, place different samples of rock in a hot oven for up to 30 minutes. Use tongs to pick them out and place in ice cold water. Caution: Take safety measures.

• To demonstrate the power of frozen water, fill a glass bottle with water. Lie it in a plastic container before placing it in a freezer for 24 hours. Take extreme safety measures!

r o e t s Bo r e p ok u S

• For the investigations on page 53, the student will require vinegar, eye-droppers, selection of different types of chalk, plastic cups, marker pens, water, access to a freezer, small glass jars with lids, box of sugar cubes, sheets of dark coloured paper, unused steel wool pads, small ziplock plastic bags and water.

• Students discuss and predict what may happen in each case. The investigations are representative of what happens in nature. Discuss with the students how each relates to weathering. Discuss why any investigation may not have given satisfactory results.

• In the rain, freeze-thaw process of physical weathering, salt crystals are often left behind when the water evaporates. As these grow, they can form a wedge which cracks the rock.

Answers

• Chemical weathering involves the reactions that take place on the surface of rock in the presence of moisture and heat. Oxidation softens rock, making it more susceptible to physical weathering. As oxygen reacts with the rock mineral, it also produces colours on the rock surface.

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• Weathering and erosion are not the same thing but they are linked.

Weathering occurs at the location of the rock. It causes fragments of rock to fall to the ground where they will continue to be affected by the forces of weathering until they are small enough to be eroded by wind, water or ice.

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• In addition to plants and animals that extend the crevices of rock, biological weathering refers to the breakdown of minerals within the rock, by lichen. Lichen is the term for tiny plants and animals that dissolve the surface of rock. It is more active in cool, damp regions.

• Some useful websites include:

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− <http://www.kidsgeo.com/geology-for-kids/0060-weathering. php>

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Earth and space sciences

1. (a) heating and cooling, ice expansion, wind, water (b) substances in the air and in rain (c) plants and animals 2. (a) 5 (b) 8 (c) 1 (d) 4 (e) 7 (f) 2 (g) 6 (h) 3 3. Plants grow in crevices in rock. Roots travel deep into crevices looking for water. As they grow, roots make the crevices wider. As animals burrow, they increase the size of crevices, allowing water to travel further into the rock where it can freeze and expand.

4. Possible answers may include: Small particles of rock, created by weathering, mix with organic matter to create soil. Minerals from the rock provide nutrients for the soil which helps the plants to grow.

5. types of rock, rock’s location, climate of location, quality of air Science as a Human Endeavour question Nature and development of science/Use and influence of science Soils are usually classified by the type of particles from which they are made—sand, silt, clay etc. Soil scientists study soil formation, classification, properties of soil and how to manage soils.

− <http://www.geography4kids.com/files/land_weathering.html> Preparation

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• Prepare a weathering cycle chart, detailing the heating and cooling of rock that leads to cracking; water seeping into the cracks, freezing and expanding to create crevices; salt deposits forming crystals on evaporation of water, that enlarge crevices; plants growing next to crevices with roots extending inwards, enlarging them further; insects and animals burrowing within crevices; lichen eating away the surface of rock; rain reacting with pollution to create acid rain that dissolves surface of rocks; constant pressure of water (rain, flowing, waves) and wind.

Page 53

1. Chalk fizzes and disintegrates; acid in vinegar reacts with salt in chalk; chemical 2. Level of ice is higher than original water level; water expands when it freezes; physical 3. With each successive shaking, cubes disintegrated further, creating more grains; constant force (friction) on cubes wears away the surface, grains at a time; physical 4. Dry pad remains the same; wet pad rusts and is more easy to break apart; iron content of steel wool is oxidised in the presence of moisture and air, giving rust; chemical

The lessons • Pages 51 and 52 should be used together.

• Discuss where students may have seen evidence of weathering in their local area; for example, well-worn pathways, smooth river stones, rocky outcrops in bushland, lichen on old stone buildings etc. While discussing the text, create a table to compare the three types of weathering.

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What is weathering? – 1 Read the text.

Weathering is the gradual destruction of rock where it stands. It can cause pieces of rock to break off larger rock formations and change landscapes so they look different. Weathering is going on all the time but it can take a very long time. The type of the rock, its location, climate and quality of air, affect how quickly rock weathers. Buildings can also show signs of weathering.

r o e t s Boby heat, water and r e Rocks are broken apartp into smaller and smaller pieces o u pressure. k S As rocks heat up during the day, they get bigger. When they cool down at night,

Weathering can occur in three ways.

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Physical weathering

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When the wind blows, it picks up small particles and they scratch off the rough surface layer of rock, making it smooth and rounded. Wave Rock in Western Australia has been moulded into its unusual shape by the action of the wind.

Rock in cliffs is also affected by other forms of weathering.

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Chemical weathering

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Water in rivers and streams smooths the surface of rocks as it gradually wears them down. Pebbles on the beach are smoothed by the waves.

Rainwater reacts with elements in the air to make an acid that eats away at the surface of rock. This makes it softer and more open to physical weathering. Acid rain caused by pollution in the atmosphere increases chemical weathering.

o c . che e r o t r s sup er Biological weathering

Plants grow in the crevices of rocks, creating a wedge. Their roots travel deeper into the crevice as they search for water. As the roots grow thicker, they make these cracks bigger.

Burrowing animals also increase the size of the crevices in rock. This allows water to penetrate deeper into the rock where it can freeze and expand.

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they get smaller again. Over time, this causes them to crack. Rainwater seeps into the cracks and turns to ice when it’s cold enough.

Because ice takes up more space than water, it splits the cracks open even further. When the ice melts, the water can flow even deeper into the rock. Eventually, parts of the rock break off.

What is weathering? – 2 Use the text on page 51 to complete the following.

1. Match each type of weathering with its cause(s). (a) Physical

•

•

plants and animals

(b) Chemical

•

•

heating and cooling, ice expansion, wind, water

(c) Biological

•

•

substances in the air and in rain

r o e t s Bo r e p ok u (a) Size of crevices increase.

S (b) Rock cracks even more and some falls away.

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2. Number each sentence from 1 to 8 to describe the cycle of one form of weathering.

(c) Rock heats up and cools down. (d) Water turns to ice and expands. (e) More ice expands.

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(f) Cracks form in the rock. (g)

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3. How can plants and animals weather rock?

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(h) Rainwater runs into crevices.

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4. How can weathering o c . che e r o t r s super 5. Weathering is a slow process that depends on:

There are different types of soil formed from the weathering of different types of rock. Find out about the different soil types and the important job soil scientists do.

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What I think will happen

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Add drops of vinegar to stick of chalk.

2. water freezing

1. acid rain on limestone rock

What to do to show the effect of:

Weathering investigations

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Cut pad in half. Place one half in ziplock bag and seal. Wet the other and place in another bag and seal. Examine daily.

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m Examine the feel and appearance . of steel wool pad. u

Examine appearance of sugar cubes.

Place 6 sugar cubes in glass jar.

Put lid on jar and shake 10 times.

Pour contents of jar on to dark coloured paper. Examine appearance of cubes and crumbs. Return chunks of sugar to jar and repeat.

4. water on rock containing iron

Mark a plastic cup at halfway point. Add water to the mark.

Freeze.

3. constant weathering on rock

What did happen?

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Why did it happen?

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Physical or chemical weathering

Where does soil come from?

Content focus: Inquiry skill focus:

The lessons

The formation and characteristics of soil

• Pages 55 and 56 should be used together.

• Students work in groups of three or four to conduct an experiment to test the permeability of three different soils.

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

• Each group places one cup of each of the soil types into a zip lock bag, labels them 1, 2 and 3. They then discuss their properties; i.e. colour, texture and particle size and record their observations in the table on page 57.

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• Explain that the purpose of the experiment is to find which of the soils collected from different places will hold onto water the longest.

This information will be helpful in deciding which location would be the best for growing vegetables.

• Students discuss and predict which soil they think will hold the most water and why.

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• The rock soil comes from is often referred to as parent rock. Parent rock is the main factor in determining the texture of soil, whether it is acidic or basic and whether it is rich in nutrients. Climate is another important factor.

• Students collect the equipment listed and conduct the experiments.

• The characteristics, composition and condition of soil determine its capacity to support life.

Answers

• Soils tend to be thin on steep slopes and thicker in valleys.

Page 56

• Natural processes can take more than 500 years to break down two centimetres of topsoil.

1. Most plants get their food from the soil and animals depend on plants or animals that eat plants for their food.

2. Soil is a mixture of minerals, organic material, water and air.

3. Weathering breaks rocks up into rock dust. It becomes soil when organic material is mixed with it and water and air.

4. (a) earthworms, insects, microbes (b) pebbles, decaying plants and animals 5. (a) sand (b) silt (c) clay 6. a mixture of sand, silt and clay 7. (a) erosion by wind and water (b) land clearing and over-farming

• An average sample of soil is about 45% minerals, 25% water, 25% air and 5% organic matter.

Page 57

• The number and size of the openings or pores between the soil particles affect the amount of water soil can contain. When all the pores are full, the soil is referred to as saturated.

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• Permeability refers to the quality of the soil which allows water and air to move through it. This is not only an important factor in plant growth but can determine the amount of run-off and how much soil is eroded by heavy rain or strong wind. It can also affect how much rainwater seeps into the ground and where it can be stored.

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• Some useful websites include:

Teacher check

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• Nutrients are added to soil by microbes causing the breaking down and decay of dead organisms. Silty soil usually contains the most nutrients.

o c . che e r o t r s super

− < http://urbanext.illinois.edu/gpe/case2/c2facts2.html>

− <www.childrenoftheearth.org/soil-facts-for-kids/soil-facts-forkids-intro.htm> − <http://42explore.com/dirt.htm>.

Preparation

• Collect three buckets of different types of dry soil; e.g. sand, clay and silt or a rich dark loam. Note: If soil with organic matter such as potting mix is used, gloves and face masks are advised.

• Label the buckets 1, 2 and 3.

• Cut each drink bottle in two about 15 cm from the bottom.

• The three filters needed for each bottle must be flexible and about 10 cm square.

As there may be some safety concerns with handling soil, it may be advisable for students to wear gloves and face masks for this activity.

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Where does soil come from? – 1 Read the text.

Soil is found on land all over the planet. It is the loose top layer of the Earth’s crust and most of the planet’s plant life need it to live. This is because most plants have their root systems in soil. The soil stops them from blowing away and the food they need comes up from the soil through their roots. Without this important natural resource, life as we know it wouldn’t exist on Earth. Animals, including humans, also depend on soil.

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Thousands of years ago, as rocks were broken up by weathering, they formed piles of smaller rocks and rock dust. As dead plants and animals decayed nearby, microbes caused them to break down. This organic matter then mixed with the rock dust to form soil. Soil is a mixture of mineral and organic materials, water and air. Both living and nonliving matter can be found in soil. Examples include, earthworms, insects and bacteria and pebbles and decaying matter.

Earth is covered in many different types of soil. The type of soil found in an area depends on the type of rock and the local climate. Some soils are very different in colour and texture and different types of plants grow in them.

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Clay has the smallest rock grains. They stick together when wet and form a hard crust when dried. Water does not drain away from clay soil and air can’t get into it very well. Although there are many nutrients in clay, plants can become waterlogged because water doesn’t drain away from their roots. Wet clay feels sticky.

Sand has the largest grains. It Silt has slightl contains tiny bits of rock and feels y larger rock g ra ins than clay, whic gritty. Sand doesn’t hold water h allow better drainage.

There are goo well and there are fewer nutrients d nutrients in s ilt which is often washe in it. This type of soil heats up d downstream and deposited as a quickly and plants growing in it river’s water fl o w down. Many p slows need to be watered regularly. lants grow we ll in silt.

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o c . che e r o t r s which is a mixture of all three. be loam, can The best soil for growing thingss up er

Although soil is formed slowly, it can easily be destroyed. This can happen through natural events such as erosion by very heavy rain, strong wind and waves or by humans removing the top and best layer of soil on building sites and by removing trees for timber or to grow crops. If the condition of the soil is poor, it can lead to water pollution. This is a problem on many farms where nutrients in the soil have been used up. Almost nothing will grow in this soil and water on it can become very salty.

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Soil can be classified into one of three types, based on the size of rock grains.

Where does soil come from? – 2 Use the text on page 55 to complete the following.

1. Explain why soil is so important.

and

.

3. Explain how soil is formed.

,

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r o e t s Bo r e p ok u 2. Soil is a mixture ofS ,

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4. Give two examples of: (a) living and (b) nonliving materials found in soil.

(b)

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5. Which type of soils:

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(a)

(a) have the largest grains?

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(b) are washed downstream?

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6. What is loam? Loam isc … e her r o t s super (c) are sticky when wet?

7. How can soil be damaged by: (a) nature?

(b) humans?

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Soil testing experiment How much water do different soils hold?

Materials: â&#x20AC;˘ 3 types of soils â&#x20AC;˘ water â&#x20AC;˘ 2-litre plastic bottle (top and base cut off) â&#x20AC;˘ cup â&#x20AC;˘ clear measuring jug

â&#x20AC;˘ 3 zip lock bags â&#x20AC;˘ rubber band â&#x20AC;˘ stopwatch

â&#x20AC;˘ 3 filters â&#x20AC;˘ 3 sticky labels

r o e t s Bo Particle size Texture r e p ok u S

Soil descriptions: 1.

3.

Prediction: Soil number

will hold in the most water.

Procedure:

Place filter over neck of bottle and attach with rubber band.

Pour 1 cup soil into bottle.

Hold neck of bottle over bottle base and gently pour 1 cup water over soil.

Set stopwatch for 10 minutes.

Move bottle away from bottle base after 10 minutes.

Pour water collected in bottle base into measuring jug and record amount.

Empty and dry bottle, replace filter and repeat for other two soils.

Results:

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Soil type

Conclusion:

Amount of water collected

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í˘ą í˘˛ í˘ł í˘´ í˘ľ í˘ś í˘ˇ

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2.

Colour

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Fair test: Was this a fair test?

Why/Why not?

How could it be improved?

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Soil type

What is erosion?

Content focus: Inquiry skill focus:

• For the activity on page 61, students will first need to research information about a local extreme weather event that caused soil erosion and changed the landscape in some way. It is suggested that possible events be retold and discussed as a class. Such events may include flooding, cyclones, extremely dry conditions over a long time, severe storms, sudden frosts, hailstorms etc.

Causes and effects of erosion Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

• Encourage students to research these events further by questioning family members about them and to collect any available photographs.

r o e t s Bo r e p ok u S

• Students could identify any natural features affected by erosion and take photos or draw them then share this information with the class.

• Model completing the first section of the chart using one of the local events.

• Students can then research with a partner or individually to complete the other sections of the chart.

• It has been established that conservation tillage techniques (that do not disturb the soil as much as traditional tillage methods), a sensible approach to grazing and keeping soil covered with vegetation, will significantly reduce erosion and conserve soil quality.

• Provide opportunities for students to share their research with other small groups and/or the class. Encourage them to ask questions and make comments about the information provided by others.

• Accelerated erosion has been an environmental problem since agriculture was first developed. It is believed to be one likely cause for the collapse of ancient civilisations.

Answers Page 60

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• Soil is a vital resource as it supports the growth of plants which are essential to our survival. The stability of soils has been reduced by human activities including agriculture and deforestation.

1. (a) Erosion moves rock, soil and sediment from one place to another. (b) wind, water, ice 2. The riverbanks are eroded away unevenly because the currents force the water to keep changing direction.

3. Glaciers move because the force of gravity pulls them down the side of mountains when they are heavy enough.

4. Waves move sand and rocks from one place to another.

5. The ice in the glacier rubs against the floor and sides of the valley, picking up rocks of all sizes that are in its way.

6. (a) less (b) The roots of plants hold on to the soil and stop it from being blown away.

7. The high winds and heavy rain in a storm are more powerful than normal winds and rain. They can cause fast-flowing floods that erode the landscape more quickly.

• The gradient of the land and the condition of the surface of the soil are also factors in soil erosion. If the soil is loose, it is more easily blown or washed away.

− <http://userpages.bright.net/~double/erode.htm> − <http://www.geography4kids.com/files/land_erosion.html> Preparation

• Collect coloured photographs that show the different natural features created by rivers and glaciers.

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• Have the students go online to find photos of natural features eroded by wind.

The lessons

• Pages 59 and 60 should be used together.

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• Some useful websites include:

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• Fertilisers and pesticides can be washed away with the run-off, damaging the environment away from the source as they find their way into rivers, lakes and coastal waters.

Page 61

Teacher check

• Explain that wide valleys we see today were created by glaciers after the last Ice Age. Narrow gorges or canyons were created by rivers.

• Discuss strategies students know of to reduce erosion; for example planting grasses to reduce erosion of sand dunes at the beach and building groynes to interrupt and lessen the impact of waves on the shore.

• Compile a ‘cause, effect, solution’ chart giving examples of soil erosion to summarise information from the discussion.

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What is erosion? – 1 Read the text.

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Erosion is happening all the time at a steady pace but sometimes it occurs more violently. Storms with high winds and heavy rains cause flooding and speed up the erosion process. Major changes to the landscape can be made within just a few hours or days.

Extreme heat and wind can cause fires that destroy trees and plants. The exposed soil is then more likely to be eroded and the landscape changed.

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Erosion is one of Earth’s natural processes. It changes the landscape by moving rock, soil and sediment from one place to another. Coastlines, hillsides and valleys have been created by the action of wind, water in rivers and waves, and ice in glaciers.

Glaciers Rivers Glaciers are slow ere A river begins on high ground wh moving rivers of ing. it is narrow, shallow and fast flow ice. They form in vel In its swift current, it picks up gra mountain areas where and silt from the riverbanks and snow falls but never ng riverbed, and rolls large stones alo melts. The snow turns to as it carves out its path. ice and each winter as mor e line ht aig str a snow falls, another layer of A river never runs in ice is formed. Eventually, the towards the sea or a lake. Currents gla cier is ns pulled down the mountainsid force the water in different directio e by the er is force of gravity. so erosion on each side of the riv er different. This is what causes a riv As it moves, the glacier ca rves out a its es ch rea er riv a en Wh . nd be to deep, wide path. It rubs ag ainst the r. end, it is wider, deeper and slowe floor and sides of the valle y, picking up everything in its way, fro m tiny pebbles to large boulders.

Glaciers can be found in mountain areas all Waves over the world. They may be as short as one hundred metres or The energy of the se as long as a as it pounds one hundred kilometres. against the shore er odes beaches and coastlines. Eve n a calm sea moves the sand Wind as the water rises and falls serts up the sion creates sand dunes in de ero ind W beach. Stronger wav de soil es and on beaches. It can also ero have enough power growing lly if there aren’t many plants cia pe es to lift and move in it. Plant roots hold on to the rocks lying at the soil, stopping the wind from foot of cliffs. blowing it away.

What is erosion? – 2 Use the text on page 59 to complete the following.

1. (a) What does erosion do?

(b) What causes erosion?

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3. Why do glaciers move?

4. How does the sea’s energy change a coastline?

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2. Explain why rivers have bends in them.

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5. Why are there lots of rocks underneath and at the sides of glaciers?

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. te o c eroded by the wind? . che e r o (b) Give the reason for your answer. t r s super

6. (a) If there are plants growing in the soil, is it more or less of it likely to be

7. Why does soil erode faster when there is a storm?

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Teac he All of these events can seriously damage property, erode soil and change the r landscape of places close to where you live, as well as in distant places.

Extreme weather research project

Extreme weather events like cyclones or unusually high or low temperatures can cause heavy rain and flooding, strong winds and forest fires.

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Elsewhere

Asia

Australia

Local

Where

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When

2. Record your information on the chart.

(b) somewhere in Australia

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(a) a place near you

Cause of erosion

(c) at a place in Asia

1. Research to find information about one of these events that caused erosion to:

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Effects on landscape

Interesting facts or comments

(d) somewhere else in the world.

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How do farming practices affect erosion?

Science as a Human Endeavour unit:

Content focus:

• Prepare three trays for the experiment on page 65. This can be done beforehand or with the students’ help before the lesson. The same amount of soil should be placed in each tray and spread evenly to ensure a fair test. Label the trays 1, 2 and 3. Leave tray 1 as it is.

Cover the soil in tray 2 with a layer of leaves or you could use grass clippings. Sprinkle grass seeds on top of the soil in tray 3.

Nature and development of science/Use and influence of science Farming practices and erosion

The lesson Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

• Pages 63 and 64 should be used together.

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• The experiment on page 65 explores how soil is protected from erosion by growing plants to slow down water flow and by absorbing the impact of raindrops with fallen leaves.

• Explain the purpose of the activity to the students and that it will take two to three weeks to complete.

• Discuss the three trays with the students. Asking them to identify the variables that are controlled; i.e. things that are the same in each tray, such as gradient, length of slope, soil type, moisture; and the one variable that has not been controlled, vegetation.

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Inquiry skill focus:

Background information

• Soil erosion by wind and water is a major concern in rural areas and one that threatens the agricultural industries of countries around the world. ‘The dust bowl’, as it was known in the United states, is an extreme illustration of how widespread and serious this problem can be. Refer to websites such as <http://www.livinghistoryfarm.org/ farminginthe30s/water_02.html>.

• Read through the procedure with the students and ask them to make some predictions.

• The experiment can be done with three prepared trays as a wholeclass activity or replicated in smaller groups.

• Students can take turns to water the trays lightly every two or three days. Explain that this is to keep the soil moist but must not cause any of the soil to be eroded.

• The rate at which soil is eroded by rain depends on the type of soil and the intensity of the rain. The gradient and length of the slope of the land and the vegetation are also important factors affecting runoff and erosion. Rainfall after drought can also result in increased erosion and run-off.

• When the grass has grown to about 1 cm, students conduct the erosion activity using each of the three trays in turn.

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• Some useful websites include:

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• After completing the experiment, students should compare the volume and colour of the runoff from each tray. Ask them to suggest reasons to explain the difference in the colour of the water. (The darker the water, the more soil it contains.)

• Some farmers are responsible for erosion caused by their farming practices such as overgrazing, not resting soil, clearing, ploughing, fertilising and irrigating land. But other practices such as deforestation, housing developments and road construction can also contribute to erosion.

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• Soil that is not anchored by vegetation is more easily blown or washed away. This can cause a reduction in crop production, lower the quality of surface water and damage the drainage of the land.

CAUTION: When handling organic potting mix, face masks and gloves are recommended. See <http://www.health.wa.gov.au/press/ view_press.cfm?id=54>

o c . che e r o t r s super Answers

− <http://www.scalloway.org.uk/phye6.htm>

Page 64

− <http://www.clarkswcd.org/Archive/PatsPageSoilEros.htm>

1. overgrazing and removal of vegetation 2. too many animals are placed in one paddock for too long 3. (a) Run-off occurs when water flows over the land. (b) Run-off washes away the soil.

4. (a) long (b) There are plenty of leaves to make enough food through photosynthesis to develop strong, healthy roots and to break the force of rain.

5. Tilling removes the vegetation so there is nothing to stop erosion by wind and water.

6. Agronomists study and learn about the land so farmers can look after their farms better.

− <http://www.sustainabletable.org/issues/soil/>.

Preparation

• Demonstrate soil erosion by placing a pile of dirt on a plastic sheet as a ‘hill’. Students can add small plastic people, buildings, trees and cars on the sides of this hill. Use a spray bottle or a hose with a spray nozzle (depending on the size of the hill) to spray water over the hill.

Continue spraying until the water causes erosion and soil and objects slide down the hill. Discuss what happened and encourage students to suggest ways of preventing this soil erosion.

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How do farming practices affect erosion? – 1 Read the text.

Erosion is a natural process which is usually in balance with other natural processes. But there are some agricultural practices that speed up erosion and damage the quality of one of Earth’s most precious resources – soil.

Overgrazing Overgrazing happens when too many animals are placed in one paddock for a long time or when the paddock is never left empty to allow time for the plants in it to regrow.

The two important jobs plant roots have in the fight against erosion are to:

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• hold on to soil and stop the wind from blowing it away • drain water from the soil by soaking it up and passing it on to the plant. This stops the soil being washed away in the rain (run-off).

When the grass is kept very short by grazing animals, the leaves are unable to make enough food to grow healthy roots so the grass begins to die. When this happens, it leaves bare patches of soil which the wind can easily erode.

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. tscientists who study how to use and look afterothe land better.

Agronomists aree c This includes land that is used for farms and forests as well. as coastal areas. By c e r looking at problems thath have occurred in the past, o these scientists find ways to e t r s s r up ehave taught farmers that the best stop them from happening in the future.

They

ways to prevent soil erosion are to not overgraze their paddocks or to remove all the vegetation from them.

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Removing vegetation ws Vegetation is anything that gro eds, in soil. When farmers plant se they want them to have the d best chance of germinating an fore growing into healthy crops. Be to planting, farmers ‘till’ the soil their remove unwanted plants and roots, and improve drainage by loosening the soil. s This may be good for the seed but it takes time for them to roots germinate and produce their ring which will protect the soil. Du this time, the soil is open to erosion by wind and rain.

The roots of any vegetation prevent erosion by holding on e to and draining the soil. Abov ground, the plants absorb the also energy of the falling rain. This prevents run-off.

How do farming practices affect erosion? – 2 Use the text on page 63 to complete the following.

1. What two agricultural practices speed up erosion?

2. What is overgrazing?

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r o e t s Bo r e p ok u S 3. (a) When does run-off happen?

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4. (a) Is long or very short grass better at preventing erosion? (b) Give the reason for your answer.

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(b) Why is run-off not a good thing in a paddock?

o c . c e he 5. Why do wind and rain cause more erosion if a paddockr has been tilled? o t r s super 6. How do agronomists help farmers?

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Plants and erosion experiment In this experiment you will find out how much soil erosion is affected by growing plants and fallen leaves.

Materials: • 1.5 kg potting mix • sprinkler can • 3 glass jars

• leaf litter • measuring cup • baking dish

• grass seed • 3 shallow trays • thick book

• water • labels • markers

r o e . t s B r e oo Procedure: p u 쐃 Place three prepared trays in a position where they allk have the same S amount of light and where the temperature is the same.

쐇 Sprinkle each tray gently with the same amount of water every two or three days to keep the soil moist. 쐋 Wait about two weeks until grass in tray 3 has grown about 1 cm high. 쐏 Place a thick book under one end of tray 1 to make a slope. 쐄 Place the other end of tray in baking dish. 쐂 Pour 3 cups water into sprinkler can. 쐆 Sprinkle water over the top of the sloping hill and watch what happens for 5 minutes. 쐊 Pour water from baking dish into glass jar and measure. 쐎 Label jar ‘tray 1’. 쐅 Repeat for trays 2 and 3 and label them.

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Results: Tray 1.

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Water colour

Description

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Water run-off

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Conclusion: Fair test: Was this a fair test?

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How could it be improved?

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Prediction: The most soil will be eroded from tray

How are objects moved by forces?

Content focus: Inquiry skill focus:

Answers

Definition of forces and how forces make things move

Page 68 1. pushing, pulling, lifting, stretching, twisting, spinning 2. (a) True (b) False (c) False (d) False 3. (a) directly (b) less 4. (a) Answers should indicate: It is the energy stored in a squashed ball that is released and causes the ball to bounce back.

5. Answers will vary but will be similar to: A balanced force is one in which forces of the same size act in opposite directions.

6. (a)

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

r o e t s Bo r e p ok u S

• Sir Isaac Newton developed a series of laws of motion. His first law states that an object in motion tends to keep going at the same speed and in the same direction unless something exerts a force on it.

However, objects do not keep moving forever. This is due to a force called friction that stops moving objects.

• Two forces are involved when a ball bounces. That is the force of the ball pushing on the floor and the force of the floor pushing on the ball. This is Newton’s third law that states that every action has a reaction. Substances like the material a ball is made from can stretch because long flexible molecules bend and stretch.

(b)

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• The measurement of force—the Newton—is named after Sir Isaac Newton.

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• Gravity is an invisible force that is applied at a distance. Because the Earth is the greatest mass its force is stronger but forces are in pairs – an action and a reaction.

• The oceans move in response to the moon’s force of gravity. The ocean’s tides are caused by the moon’s gravity trying to ‘pull’ anything on Earth towards it, but only the water is affected as it is always moving. Each day, as the oceans rise and fall, there are two high tides and two low tides.

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• The website < http://www.bbc.co.uk/schools/scienceclips/ages/6_7/ forces_movement.shtml> has a very simple game for students to play to use different pushes and pulls, sizes of objects, and gradients to see how far objects move.

Preparation

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• As a class, find and discuss different objects in the classroom, in the playground or at home which require a ‘push’ or a ‘pull’ to make them work. Examples may include pushing or pulling a door to open it, pencils which require both a push and a pull to work etc.

Physical sciences

The lessons

PUSH experiment: Teacher check answers. The air in the balloon provides a forces which pushes it and makes it move.

PULL experiment: Teacher check answers. The weight of the marbles in the bucket creates a pulling force on the rubber band making it stretch and become longer.

• Pages 67 and 68 should be used together.

• Allow the students to read the text on page 67 independently. Assist them with any unfamiliar vocabulary if necessary, then discuss the information and concepts.

• Students may need to work in pairs to set up the experiments on page 69. As with all experiments, discuss after completion to reflect on what worked well (or not very well), and any improvements which could be made to obtain a better, or different, result if it was repeated.

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How are objects moved by forces? – 1 Read the text.

r o e t s Bo r e p ok u S

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Objects cannot move by themselves. They need some kind of force to make them move. Forces cause objects to speed up, slow down or change direction. The greater the mass of an object, the more force is needed to start or stop it moving.

An object can be made to move by pushing, pulling, lifting, stretching, twisting or spinning forces acting on it.

Forces move in a particular direction and are usually shown on a diagram with arrows. The arrows show the direction in which the force is acting.

Forces such as pushes, pulls and collisions are applied directly and transfer energy to an object. When a ball is kicked, energy from the foot is transferred to the ball, sending it in the direction and at the speed the player wants. When you throw a ball, a similar transfer of energy from your arm to the ball occurs.

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Some substances can be stretched or squeezed when a force is used to pull or push them. But these substances spring back into their original shape when the force is removed. Many balls are made from materials that stretch like this. So when a ball hits a wall, it is squashed a bit then it springs back into shape. As it springs back, the energy stored in the squashed ball is released. This is the force that causes the ball to bounce back again.

. te o Gravity is a natural force, exerted from a distance, which causes a mass to attract c . c ethe greatest mass, all and be attracted by anyh other mass. Because the Earth has r e o t towards it. The famous r other objects with a smaller mass are pulled downwards s s r u e p scientist Sir Isaac Newton used the example of an apple dropping from a tree and falling to the ground, to explain this theory. Objects have weight on Earth because gravity pulls them down.

Forces are said to be balanced (or equal) if they are the same size but acting in opposite directions. If balanced forces are acting on an object, the object will not change its motion. If it is still, it will remain still. If it is moving, it will continue moving in the same direction and at the same speed. Unbalanced forces change the way an object is moving by making objects start to move, speed up, slow down, or change direction.

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Friction is another directly applied force. A rolling ball would continue to roll along without stopping if it wasn’t for the force of friction acting on it. A ball rolling along a rough surface slows down and stops quicker than one rolling along a smooth surface. This is because the force of friction between the two surfaces is greater.

How are objects moved by forces? –2 Use the text on page 67 to complete the following.

1. What are six common ways forces can move an object?

2. Which statements are True or False? (a) An object with a greater mass needs more force to move it.

r o e t s Bo r e p ok u (c) An apple falling Sfrom a tree is an example of friction. (d) The greater the pull of gravity, the less an object weighs.

3. (a) Is friction a force that is applied directly or at a distance? (b) Is friction greater or less between smooth surfaces?

4. Explain the force that causes a ball to bounce.

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C.Publ i cat i ons •af o rr eforce vi e w pur posesonl y• Explain what balanced is.

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5.

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(b) Objects move in the opposite direction to the force being exerted on them.

6. Draw an arrow to show the direction of the force being applied by people in each picture. (a)

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(c)

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Pushing and pulling experiments Complete the following experiments to find out about forces.

Balloon rocket push

Rubber band weight pull

Materials:

Materials:

â&#x20AC;˘ balloon â&#x20AC;˘ drinking straw â&#x20AC;˘ scissors â&#x20AC;˘ fishing line/cotton about 4-5 m long â&#x20AC;˘ 2 chairs â&#x20AC;˘ masking tape

â&#x20AC;˘ long ruler or length of wood â&#x20AC;˘ pencil â&#x20AC;˘ 2 tables â&#x20AC;˘ strong rubber band â&#x20AC;˘ paper strips â&#x20AC;˘ small plastic bucket â&#x20AC;˘ strong wire â&#x20AC;˘ marbles â&#x20AC;˘ scissors

1. Steps:

r o e t s Bo r e p ok u S

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í˘ą Thread fishing line through straw.

1. Steps:

í˘˛ Place chairs about 4 m apart and tightly tie fishing line between chairs.

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í˘ą Attach wire to bucket handle to form hook.

í˘˛ Slip rubber band over wood to middle.

í˘ł Move straw to one end of line. í˘´ Blow up balloon and twist open end to seal.

í˘ł Place wood between tables. í˘´ Attach hook to rubber band to suspend bucket.

í˘ľ Tape inflated balloon to straw.

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C.Publ i c t i o ns í˘ľa Cut strip of paper the same length as rubber band (with Predict what will happen to the â&#x20AC;˘ f o r r e v i e w p u r p o s eso ywrite â&#x20AC;˘0 on it. bucket onn it) l and balloon. í˘ś Release neck of balloon.

3. Write the results and an explanation (or analysis) for what happened.

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o c . che 3. Cut new strip of paper the e r same length as rubber band o t r s super and write 1 on it.

4. Add marbles, ten at a time, cutting and labelling strips of paper after each addition until 51 marbles are in bucket.

4. On the back of the worksheet, write comments about the activity. Tell what you liked about the experiment, what worked and what didnâ&#x20AC;&#x2122;t and any improvements you would make if you repeated the experiment.

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5. Write an explanation for what happened on the back of the worksheet.

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2. Predict what will happen to the rubber band when one marble is added to the bucket.

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How do forces change movement and speed?

Content focus: Inquiry skill focus:

Preparation

The relationship between speed, mass and force

• The concepts introduced in the text may be quite challenging for some students. It is suggested that it be read and discussed with the class.

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

The lessons • Pages 71 and 72 should be used together.

• The force with which the marble in the investigation on page 73 hits the modelling clay increases with distance. Some students may realise that the marble is accelerating as it falls and this too increases the force needed to stop it.

r o e t s Bo r e p ok u S Answers

Page 72

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• Gravity is a force that acts between any two objects and pulls them together causing them to accelerate at 9.8m/sec2. This explains why the mass of an object doesn’t affect the rate at which it accelerates towards the Earth. However its speed can be affected by its surface area because of increased or decreased air resistance. A parachute is a typical example of this.

1. People can’t see or feel the forces because if they are balanced, nothing changes.

2. There is an equal force pushing up which balances the force of gravity.

3. (a) Yes (b) Gravity causes objects to fall to Earth at the same speed.

4. (a) to the right (b) to the right (c) down (d) stay 5. Net force is the force that different forces together exert on an object.

6. (a) the empty cart (b) an egg 7. (a) a car (b) a mouse

• The force of attraction between two objects depends on the size of the objects and the distance between them. As the Earth is by far the biggest object, gravity is observable when objects are being pulled down towards its centre, and are seen to be falling.

• The moon’s gravity is less than the Earth’s as it is smaller. So objects have less weight on the moon. However, gravity is stronger on Saturn and Jupiter because they are bigger. So the same object would weigh more on these planets.

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• Forces acting in opposite directions are subtracted, or added when acting in the same direction. The net force is the overall force when combined. Unbalanced forces determine whether an object will slow down, speed up or change direction.

Page 73

Teacher check

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• Force is measures in newtons. The force of gravity on a 100 g apple is about 1 N and a car moving forward is about 4 000 N.

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• Speed and the force needed to stop an object are related to its mass.

Moving or stopping an object with a greater mass requires more force.

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• Inertia is also a force. It resists change so it needs to be overcome in order for an object to move or to change the speed at which it is moving. For example, the forces working on an object moving at 60 kph are balanced to maintain this speed and inertia needs to be overcome in order for it to slow down, accelerate or change direction.

Physical sciences

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• Newton’s first, second and third laws of motion are relevant to the work in this section. These concepts have been simplified but students may benefit from investigating them in books or on the internet as a follow up activity.

• Visit the website <http://www.sciencehelpdesk.com/unit/ science2/1> to find free animated videos about forces and movement which simplify and clarify many of the concepts introduced in the text.

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How do forces change movement and speed? – 1 Read the text.

Most people are unaware there are always forces acting on them and on everything around them. We can’t see or feel these forces because if they are balanced, they don’t cause any noticeable changes in movement. Everything stays the same.

r o e t s Bo r e pSir Isaac Newton, who was born ok in 1642, worked out u only sensible answer to this question was that there S the had to be an equal and opposite force pushing us up.

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Many of us have heard about gravity and know that when we are standing on the ground, gravity is pulling us down towards the centre of the Earth. So then the big question is, why doesn’t gravity pull us and everything else down into the centre of the Earth?

Since then, other scientists have decided he was right!

Forces work in pairs and they are usually in balance.

The force of gravity pulls everything down at the same speed. If two objects of the same size and shape are dropped, they will both fall at the same speed and hit the ground at the same time even if one of them is much heavier than the other.

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C.Publ i cat i ons Forces are measured in newtons and shown on •f orr ev i ew p u r pose so nl y • in the diagrams and illustrations with arrows pointing

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Newton also discovered that things are lazy and like to stay where they are or to just keep on moving at the same speed until acted on by a new force. To make a change to any object where the forces acting on it are in balance, a new force has to overcome the force keeping things the same. This ‘laziness’ force is called inertia.

The force needed to cause things to move faster or stop depends on how heavy the object is. It needs greater force to make a heavier object accelerate or stop than a lighter one. So if you wanted to throw a ball faster you would need a greater force. If you threw a heavier ball, it would reach the bat after a lighter ball thrown with the same force.

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direction of those forces. Longer or sometimes wider arrows are used to show stronger forces. A stronger force will overcome a weaker force and move an object in its direction or stop it. To find out the size of this force the smaller force is subtracted from the bigger one.

This new force is called the net force. It is the net force which determines what happens to an object. A bigger force will move an object further and faster or slow it down or stop it quicker.

How do forces change movement and speed? – 2 Use the text on page 71 to complete the following.

1. Why don’t people realise there are forces acting on them all the time?

2. Explain why gravity doesn’t pull everything into the centre of the Earth.

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tower hit the ground at the same time? Yes

No

(b) Why/Why not?

4. Look at the forces on each object. Would the objects move to the left, right, up, down or stay? (a)

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r o e t s Bo r e p ok u 3. (a) Would a light tennis S ball and a heavier cricket ball dropped from a tall

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(d) 5. What is a net force?

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. t e o 6. Which would move faster if the same force was applied: c . c e r (a) a cart full of sand or h an e empty cart? o t r s super (b) a rock or an egg?

7. Which would need less force to stop: (a) a truck or a car?

(b) a mouse or a cat?

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Force and distance Work with a partner to complete the following investigation to find out if increasing distance increases force.

Materials: â&#x20AC;˘ metal or plastic tray â&#x20AC;˘ large sheet of paper â&#x20AC;˘ glue

â&#x20AC;˘ marble â&#x20AC;˘ soft modelling clay â&#x20AC;˘ scissors â&#x20AC;˘ marker pen â&#x20AC;˘ chair or small stepladder

â&#x20AC;˘ ruler â&#x20AC;˘ Blu-tackâ&#x201E;˘

r o e t s B r e ooMark and label 0 cm, í˘ą Make a paper p ruler 200 cm long and 15 cm wide. u kon it.

30 cm, 60 cm, 90 cm, 120 cm, 150 cm and 180 cm S í˘˛ Vertically attach your ruler to the wall, with 0 cm mark at floor level.

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1. Steps:

í˘ł Put a thick, flat layer of clay inside the tray, and place it on floor.

2. Prediction: What will happen as the marble drops from different heights?

3. Experiment: Drop the marble into the tray from the different heights given in the table, measure the size of the dent and record your results.

120 cm

60 cm

150 cm

90 cm

180 cm

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30 cm

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C.Publ i cat i ons â&#x20AC;˘f orDent r ev i ewDistance pur po sesonl yâ&#x20AC;˘ Distance size Dent size

o c . che e r o t r s r u e 5. Conclusion: What did the s size ofp the dent tell you about the force on the marble?

6. Reflection: Use the back of the worksheet to record any difficulties you had with the experiment. List any improvements you would make if you repeated the activity. Was this a fair test? Explain your answer.

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4. What happened when you increased the distance of the drop?

What are magnets? How do they work?

Content focus: Inquiry skill focus:

The lessons

Magnets produce forces which attract or repel materials and each other

• Pages 75 and 76 should be used together.

• Allow the students to read the text on page 75 independently. Assist them with any unfamiliar vocabulary if necessary, then discuss the information and concepts.

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

Background information

Answers

r o e t s Bo r e p ok u S Page 76

1. Answers will vary but will be similar to ‘A magnet is an object or material which creates a force called a magnetic field’.

2. The poles of a magnet are named North and South, the same as two cardinal points of a compass.

3.-4. Teacher check – Refer to diagrams on page 75.

5. Like poles repel each other; Unlike poles attract each other.

6. (a) … iron, nickel, cobalt and steel (b) … that a permanent magnet has magnetism all the time, but an electromagnet only acts as a magnet while the current is flowing. (c) Teacher check. Answers may include fridge magnets, doorbells, games, cupboard door mechanisms, credit card strips, microphones and toys. Other answers from the students may need to be discussed.

Science as a Human Endeavour question Nature and development of science Refer to teachers notes for information about William Gilbert, Hans Christian Oersted and Andre Marie Ampere, and websites such as <http://www-istp.gsfc.nasa.gov/Education/Imagnet.html>.

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• A magnet exerts an invisible force which can either make an object move away from or towards it. If contact between two magnets is established, it is maintained by the magnetic field.

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• Knowledge about magnetism dates back to the ancient Greeks and the early Chinese. The use of the magnetic compass gradually spread to Europe. Columbus used a magnetic compass when he crossed the Atlantic Ocean.

• The English scientist William Gilbert’s research, printed in 1600, provided the basis for the science of electricity and magnetism.

• More was discovered about magnetism by Danish scientist Hans Christian Oersted and Andre-Marie Ampere. Ampere deduced that magnetism was basically a force between electric currents. Michael Faraday, after whom the farad electric unit is named, proposed the idea of magnetic field lines of force.

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By completing the experiment on page 77, the students should be able to see the magnetic field lines because the iron filings will form this pattern.

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• Other common uses of magnets include audio cassettes; electric motors and generators; Magnetic Resonance Imaging (MRI); metalworking chucks; vinyl magnetic strips to hang artworks from metallic surfaces; transformers; jewellery clasps; magnetic levitation transport(maglev), and scrap and salvage machines.

(Refer to <http://en.wikipedia.org/wiki/Maglev_%28transport%29> for further information about maglev.)

• An object such as an iron nail may be magnetised by running or stroking a magnet over it a few times. However, this effect is temporary.

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• The website <http://www.kidcyber.com.au/topics/magnets.htm> has a list of weblinks about magnets and magnetism. Useful background information may be found at <http://www.factmonster.com/ce6/sci/ A0831162.html>. Visit <http://www.bbc.co.uk/schools/ks2bitesize/ science/physical_processes/magnet_springs/play.shtml> to play simple interactive games relating to magnetism.

Physical sciences

Preparation

• It would be ideal if students had the opportunity to freely explore magnetism using a variety of magnets and materials before completing this group of pages.

• Collect the resources needed for the experiment on page 77.

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What are magnets? How do they work? – 1 Read the text.

A magnet is any object or material, usually metallic, which produces an invisible force called a magnetic field. This force allows it to attract some metals and to attract or repel other magnets from a distance.

r o e t s Bo r The poles of a magnet attract each other. The lines e p of force of the magnetic fio eld start at, and exit from, u the north pole. They end, ork enter, at the south S pole. The lines of force are closer together and

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Teac he r

A magnetic compass needle moves freely around a pivoting point. One end of the needle always points to the north, and the other end points to the south.

The ends are called the poles.

stronger (concentrated) near the poles and further apart at other places. The lines of force do not cross each other and are shown on diagrams with arrows which indicate the direction of the force.

Two magnets, held close together, will create pushing or pulling forces on one another.

These forces are strongest at the poles of the magnets. When the same poles on two magnets are held close together, the magnets will push away from, or repel, each other. Same (or like) poles repel. When different poles of two magnets are held close together, the magnets will pull towards, or attract, each other. Opposite (or unlike) poles attract.

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o c . Magnetic chematerials as well as otherr Magnets can attract magnetic magnets. e o materials include iron, nickel, r cobalt and steel. t s s r u e p Some magnets have stronger magnetic fields than others. Stronger magnets will create bigger pushing or pulling forces. Magnets may also vary in shape and size.

A permanent magnet, such as a bar magnet, is magnetic all the time; its force cannot be turned off. An electromagnet can be made by passing an electric current through a coil of wire. The electromagnet stops acting as a magnet as soon as the current is turned off.

Magnets have many uses including fridge magnets, doorbells, games, cupboard door mechanisms, credit card strips, microphones and toys.

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What are magnets? How do they work? – 2 Use the text on page 75 to complete the following.

1. Write a definition of a magnet, in your own words.

2. How do the poles of a magnet relate to the points of a compass?

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5.

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3. Complete the diagram by adding the poles, magnetic field lines and arrows for the direction of the forces on the magnetic field.

r o e t s Bo r e p ok u 4. Complete the diagrams by using S arrows to show which poles are

attracted to each other and which ones repel each other.

magnet

N

S

S

N

N

S

N

S

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C.Publ i cat i ons Write the two statements which tell about the attraction and repulsion between •f orr evi ew pur posesonl y• similar and different poles of a magnet.

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6. Complete the sentences.

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(a) Materials which are attracted to magnets include

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. o c . ch (b) The main difference between a permanent magnet r and an electromagnet e er o st super is . (c) Two uses of magnets are

and

.

Find out what scientists such as William Gilbert, Hans Christian Oersted and Andre Marie Ampere discovered about magnets and magnetism.

Use internet or library resources.

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What does a magnetic field look like?

Complete the following experiment to see what a magnetic field looks like.

Materials: â&#x20AC;˘ bar magnet

â&#x20AC;˘ iron filings

â&#x20AC;˘ shaker

â&#x20AC;˘ sheet of paper

â&#x20AC;˘ plastic wrap

r o e t s Bremoval of iron filings. r e í˘ą Wrap magnet in plastic wrap to allow easy o p ok u í˘˛ Place iron Sfilings in shaker.

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1. Steps:

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í˘ł Place paper on top of magnet.

2. Prediction: What pattern will the iron filings make when sprinkled onto the sheet of paper?

3. Sprinkle the iron filings on top of the paper and draw the pattern that appears. Was this the same as your prediction?

. tedifficulties which may have occurred during theoexperiment and 4. Record any c . what you liked or disliked. Say what seemed to work and what did not work. c e h r List any improvements you would make if you repeated the experiment. e o t r s s r u e p Use the back of the worksheet for recording.

5. With a partner, discuss and predict what might happen if the experiment was repeated with the following variables: (a) two magnets placed in different positions near each other. (b) a magnet of different size or shape was used.

6. With a partner, list any other experiments you could do with magnets.

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What is friction?

Content focus: Inquiry skill focus:

The lessons

Friction and how it relates to movement

• Pages 79 and 80 should be used together.

Questioning and predicting Planning and conducting Processing and analysing data and information Evaluating Communicating

• Allow the students to read the text on page 79 independently. Assist them with any unfamiliar vocabulary if necessary, then discuss the information and concepts.

• Introducing testing friction on page 81. − Allow the students to practise rolling their cars to check that the two they have selected generally move at a similar speed.

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− The four tracks do not need to be completely covered with the test material but the same amount needs to be attached to each track.

Background information

− After the students have determined which surfaces have the greatest and least friction, discuss whether the activity involved a fair test or not. (Fair tests are those that have only one variable at a time changed.)

• The types of surfaces, together with the force pressing them together, determine the amount of friction. Examples include:

Answers

− rough carpet or smooth marble tiles

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− an empty trailer or one filled with sand.

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• Friction is a direct contact force that opposes motion, making it more difficult for objects to move across a surface. Speed is inversely proportional to friction.

1. Answers will vary but should indicate that friction is an invisible force that tries to stop objects from moving.

2. Friction tries to stop the car from moving so it needs move power to drive against it.

3. Heat can cause wear and tear.

4. They would help to stop the car from slipping on the roads and causing accidents.

5. (a) No (b) When objects move in air and water, they create friction which tries to stop motion.

6. (a) false (b) true (c) false (d) false (e) true (f) false (g) true

• Friction is very important and beneficial in everyday life. There are many things that would be impossible without friction. For example, friction holds a shoe to the ground to make walking possible.

• Friction can also be a nuisance by limiting movement and in some cases requiring lubricants such as oil to reduce friction and facilitate motion. Friction also wastes energy because extra energy is needed to produce the power to overcome it.

• Air and fluid resistance are forms of friction. Aircraft and boats need to counter these forms of friction in order to move.

• Any device with moving parts wears out as a result of friction. This is mainly because of the heat energy produced by friction,

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• The website <http://www.teachengineering.com/view_activity. php?url=http://www.teachengineering.com/collection/cub_/ activities/cub_human/cub_human_lesson03_activity1.xml> provides lesson plans and activities on friction related to the human body and its joints.

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1.–3. Teacher check 4. The fastest track should be the one covered with aluminium foil. The slowest will be the one covered with towelling material.

5. The faster the car moves, the less friction of the material there is restricting the movement.

6. Teacher check

• The website <http://www.bbc.co.uk/schools/ks2bitesize/science/ physical_processes/friction/play.shtml> has activities relating to friction.

Preparation

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• Discuss possible reasons to explain why a wet ball is so much more difficult to hold and control than a dry one. Introduce the concept of friction to explain this and encourage students to describe any difficulties they have experienced when attempting to walk or run on slippery surfaces.

• Collect all the materials required for the activity on page 81.

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What is friction? – 1 Read the text.

Friction is an invisible force that exists between an object and the surface it moves along. It makes it difficult for an object to move across the surface because it works against the forces producing movement. Friction is a direct contact force that resists and reduces the speed of motion.

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The amount of friction depends on the force pressing the two surfaces together and the type of surface. Some surfaces produce little or no friction and an object will move quite easily for some distance across it. A bowling ball will, for example, travel very smoothly along the polished floor of a bowling lane. But other surfaces may produce so much friction that an object needs a very big force to move it and it may only travel a short distance before friction stops it again.

The bowling ball, for example, wouldn’t travel as quickly or as far across a floor with thick carpet on it.

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Think about a car rolling along a road without its engine running. The friction between the car’s tyres and the road will eventually cause it to stop. If the car had smooth tyres and the road was smooth too, it would travel further than it would if the tyres and the road were rough. Drivers choose the type of tyres they put on their cars to suit the roads they travel on. If their tyres didn’t provide enough friction, they would slide all over the road when trying to stop. However a disadvantage that affects motorists is their cars waste energy by using extra fuel to drive against the force of friction. Aircraft also waste energy because of friction caused by air resistance, as do ships because of friction with water.

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When choosing footwear, people who play particular sports have to consider the amount of friction they’ll need to play their sport. For example, footballers need studs on their boots for added friction to stop them sliding around, especially on wet grass. But a disadvantage for them is that the friction they need causes heat and wear and tear on their boots and they need to replace them regularly.

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Friction affects many things we do in our everyday lives. It can help us and make things easier or it can make things we do more difficult. Simple activities like walking and writing would be impossible without friction holding our shoes to the ground and keeping a pencil in our hand.

What is friction? – 2 Use the text on page 79 to answer the following.

1. In your own words explain what friction is and how it works.

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2. Explain why friction costs motorists more money for fuel.

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3. Explain why the heat friction produces can be a disadvantage.

4. Why would tyres with greater friction be helpful to people driving on icy roads?

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(b) Explain your answer.

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5. (a) Is the force of friction only experienced on land? Yes

o c . (a) You can see friction. che e r o t r (b) Friction helps people to walk.s s uper

6. Write true or false after each statement.

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(c) Friction is always helpful. (d) Smooth tyres produce more friction. (e) Objects move faster if there isn’t a lot of friction. (f) Friction is a force that is exerted at a distance. (g) Friction affects many things we do in our everyday lives.

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Testing friction Work in a group to test the friction of different materials.

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Materials: â&#x20AC;˘ large sheet thick, strong cardboard â&#x20AC;˘ 2 small toy cars â&#x20AC;˘ 2 tissue boxes â&#x20AC;˘ stapler â&#x20AC;˘ sheets of sandpaper â&#x20AC;˘ polyester fabric â&#x20AC;˘ towelling material â&#x20AC;˘ aluminium foil â&#x20AC;˘ scissors 1. Steps: í˘ą Divide the cardboard into four sections to make four tracks on a ramp. Cover one section of track with sheets of sandpaper, one with aluminium foil, one with polyester fabric and the other with towelling material. í˘˛ Use stapler to attach materials to tracks. í˘ł Place tissue boxes together under one end of ramp.

2. Prediction: What will happen when the cars go down the different tracks?

Which material is on the fastest track and which is the slowest track?

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C.Publ i cat i ons Tracks Test one Test two Test three â&#x20AC;˘ f o r r e v i e w p u r p o s e s o n l y â&#x20AC;˘ Foil vs sand paper

3. Experiment: Race cars down tracks three times each and record winners.

Foil vs towelling

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Towelling vs sand paper Towelling vs polyester

. tefastest track was 4. Results: The . The o c . che slowest track was . e r o t s s r upofe 5. Conclusion: What doesr the speed the cars tell you about the friction of Polyester vs sand paper

the materials used in this experiment?

6. Reflection: Use the back of the worksheet to record any difficulties which may have occurred. Say what you liked or disliked and what seemed to work and what did not work. List any improvements you would make if you repeated the activity.

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Foil vs polyester