Write secret messages, make a colour explosion and have fun with chemistry!
WARNING
Not suitable for children under 8 years. For use under adult supervision. Read the instructions before use, follow them and keep them for reference. Contains some chemicals which present a hazard to health. Do not allow chemicals to come into contact with any part of the body, particularly the mouth and eyes. Keep small children and animals away from experiments. Keep the experimental set out of reach of children under 8 years old. This product contains balloons. Warning! Children under eight years can choke or suffocate on uninflated or broken balloons. Adult supervision required. Keep uninflated balloons from children. Discard broken balloons at once. Made of natural rubber latex. Small parts (choking hazard). Sharp edges. Image shown is for illustrative purposes only, parts or colours may differ. Save all information for future reference. Additional common household materials may be required.
15 experiments
Dear parents and guardians
Through play, children develop different cognitive skills. Scientific studies show that when we are having fun or making discoveries during an experiment, a neurotransmitter called Dopamine is released.
Dopamine is known to be responsible for feelings like motivation, reward and learning and that’s why experiences are related to positive feelings. So, if learning is a positive experience, it will stimulate the brain to develop various skills.
Therefore, Science4you aims to develop educational toys that combine fun with education by fostering curiosity and experimentation.
Find out below which skills can be developed with the help of this educational toy!
Concentration
Vocabulary
Social skills
Reasoning
Learning
The educational feature is one of the key strengths of our toys. We aim to provide toys which enable children’s development of physical, emotional and social skills.
1st Edition 2024
Lisbon, Portugal
Author: Inês Martins
Scientific Review: Ana Garcia
Revision: Joana Gomes and Rita Amaral
Conformity Revision: Rute Cesário and Susana Ferreira
Project Management: Inês Martins and Joana Lemos
Product Development: Ana Garcia
Pagination: Joana Gravata, Filipa Rocha and Mariana Moleiro
Illustrations: Joana Gravata
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission in writing or, as expressly permitted by law, or under terms agreed with the appropriate reprographic rights organization. Any unauthorised use of this book, or any violation of this book’s rights, allows the company, to be fairly compensated in legal terms, and not excluding criminal liability for those who are responsible for such violations.
SAFETY RULES
GENERAL FIRST AID INFORMATION
ADVICE FOR SUPERVISING ADULTS
LIST OF SUBSTANCES SUPPLIED
DISPOSAL OF SUBSTANCES
KIT CONTENTS
1. Experiments
1.1. Mixtures of substances and solutions
Extra Experiment. Comparing different mixtures
1.2. Separating mixtures
Experiment 1. Preparing a filter
Experiment 2. Separating water and sand
Experiment 3. Chromatography
1.3. Diffusion
Extra Experiment. Do water molecules really move?
Experiment 4. Diffusion
1.4. Density
Experiment 5. Almost a lava lamp
Experiment 6. Coloured cup
1.5. The pH of substances
Experiment 7. The pH of substances
Experiment 8. Coloured secret messages
1.6. Oxidation
Experiment 9. Secret messages with lemon
Extra Experiment. Why do cut apples turn brown?
1.7. Surface tension
Experiment 10. Colour explosion
1.8. Crystals
Experiment 11. Crystals
Extra Experiment. Stalagmites and stalactites
1.9. Production of carbon dioxide
Experiment 12. Foam column
Experiment 13. How to fill up a balloon without blowing
Experiment 14. Volcanic eruption
Extra Experiment. Foam with egg white
1.10. Osmosis
Experiment 15. How jelly sweets behave when in the presence of different solutions
1.11. Fluids and solids that can be moulded
Extra Experiment. Solid or liquid
1.12. Molecules
Extra Experiment. Make fantastic molecules!
2. Quiz
SAFETY RULES
- Read these instructions before use, follow them and keep them for reference.
- Keep young children and animals away from the experimental area.
- Store this experimental set and the final crystal(s) out of reach of children under 8 years of age.
- Clean all equipment after use.
- Make sure that all containers are fully closed and properly stored after use.
- Ensure that all empty containers and/or non-reclosable packaging are disposed of properly.
- Wash hands after carrying out experiments.
- Do not use any equipment which has not been supplied with the set or recommended in the instructions for use.
- Do not eat or drink in the experimental area.
- Do not allow chemicals to come into contact with the eyes or mouth.
- Do not replace foodstuffs in original container. Dispose of immediately.
- Do not apply any substances or solutions to the body.
- Do not grow crystals where food or drink is handled or in bedrooms.
- Take care while handling with hot water and hot solutions.
- Ensure that during growing of the crystal the container with the liquid is out of reach of children under 8 years of age.
GENERAL FIRST AID INFORMATION
- In case of eye contact: Wash out eye with plenty of water, holding eye open if necessary. Seek immediate medical advice.
- If swallowed: Wash out mouth with water, drink some fresh water. Do not induce vomiting. Seek immediate medical advice.
- In case of inhalation: Remove person to fresh air.
- In case of skin contact and burns: Wash affected area with plenty of water for at least 10 min.
- In case of doubt, seek medical advice without delay. Take the chemical and its container with you.
- In case of injury always seek medical advice.
ADVICE FOR SUPERVISING ADULTS
- Read and follow these instructions, the safety rules and the first aid information, and keep them for reference.
- The incorrect use of chemicals can cause injury and damage to health. Only carry out those experiments which are listed in the instructions.
- This experimental set is for use only by children over 8 years.
- Because children’s abilities vary so much, even within age groups, supervising adults should exercise discretion as to which experiments are suitable and safe for them. The instructions should enable supervisors to assess any experiment to establish its suitability for a particular child.
- The supervising adult should discuss the warnings and safety information with the child or children before commencing the experiments. Particular attention should be paid to the safe handling of acids, alkalis and flammable liquids.
- The area surrounding the experiment should be kept clear of any obstructions and away from the storage of food. It should be well lit and ventilated and close to a water supply. A solid table with a heat resistant top should be provided.
- If materials which have not been supplied with the set are suggested and used, make sure that they are suitable for this purpose and that they are in good condition (i.e. storage and shelf life).
- This set contains colourings (pigments). Colourings can stain. Keep it away from objects and fabrics.
- This set contains gloves which may be made from natural rubber latex. Natural rubber latex may cause allergies.
In case of poisoning by any of the components used in this set, contact the anti-poison centre or the nearest hospital.
Please consult the following link for more information: UK https://www.npis.org/ EU https://poisoncentres.echa.europa.eu/appointed-bodies
In case of emergency dial:
EU 112 | UK 999 | USA & CAN 911 | AU 000
LIST OF SUBSTANCES SUPPLIED
Sodium Bicarbonate NaHCO3 (CAS 144-55-8)
INGREDIENTS: SODIUM HYDROGEN CARBONATE
Red Colouring
INGREDIENTS: WATER, PHENOXYETHANOL, CI 16255, SODIUM BENZOATE, POTASSIUM SORBATE
Recommendations for substances and mixtures: Do not ingest. Avoid contact with the eyes and mouth. Use only according to the instructions. Store in tightly closed containers. Keep in a cool, dry place. Protect from moisture, direct sunlight and heat sources.
DISPOSAL OF SUBSTANCES
Do not dispose of substances and / or mixtures with domestic waste and household waste. For more details, contact a competent authority. To dispose of the packaging, use the collective collection points.
KIT CONTENTS
Gloves
Large measuring cups
Small measuring cups
Wooden spatulas Paper filters
Red colouring
Test tubes with lid
Pasteur pipettes
pH test strips Balloons
Hello, scientist! Are you ready to become a real chemist?
1. Experiments
Before you start, you should learn how to correctly use the Pasteur pipette. Pasteur pipettes are measuring instruments used in the laboratory to transfer small quantities of liquids between containers. Because it is possible to count drops with a Pasteur pipette, it is often called a dropper.
1.1. Mixtures of substances and solutions
KNOWING MORE...
Matter can be presented as a pure substance or as a mixture. Do you know the difference between a substance and a mixture? A substance consists of atoms or molecules, with a characteristic composition and a defined set of properties. It can be simple when it consists of a single chemical element (such as gold and iron), or compound when formed by more than one type of atoms (such as water, salt and sugar). Mixtures are composed of two or more substances. We can divide mixtures in homogeneous, heterogeneous and colloids. To a homogeneous mixture we can also call a solution. A solution consists of, at least, one solvent and one solute. A solvent is a substance capable of dissolving another, while a solute is a substance that dissolves in another.
EXTRA EXPERIMENT
Comparing different mixtures
What will you need?
Material included in the kit:
• Gloves • Wooden spatula • Large measuring cups
Water
Extra material:
Cooking oil
Orange juice
Steps:
1. Fill half of the large measuring cups with water.
2. Add olive oil to one of the cups and orange juice to another, and mix with the wooden spatula.
What type of mixtures do we have in each cup?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
The mixture of water and orange juice is a homogeneous mixture. The intermolecular forces between the water molecules are of the same type of the ones in orange juice. This way, water molecules establish the same type of interactions with the orange juice. This results in the miscibility of both liquids, allowing them to get mixed. As so, in a homogeneous mixture or solution, the mixture has a constant aspect, in which it is not possible to distinguish its components, not even with a microscope. The mixture of water with olive oil is a heterogeneous mixture. In this type of mixtures we can distinguish perfectly its components with the naked eye. The interactions between molecules are different in these mixtures. Water and olive oil molecules have different properties which makes them immiscible.
1.2. Separating mixtures
KNOWING MORE...
In some situations we only need one of the substances present in a certain mixture, and for that a specific method of separation is required. There are several ways to separate mixtures and, to choose the most appropriate one, we have to consider the mixture we are dealing with. The first step is to determine if the mixture is homogeneous or heterogeneous and then choose the proper process to make the separation.
Immiscible fluids are liquids that don’t get mixed.
EXPERIMENT 1
Preparing a filter
What will you need?
Material included in the kit:
Funnel
Paper filter
Steps:
Gloves • Pasteur pipette
Extra material: • Water
1. Fold the filter as shown in the image below. Then put it inside the funnel.
Image 1. Assembling scheme of a filter in a funnel. Key Words: mm - millimetres.
2. With the Pasteur pipette, add some drops of water in order to better attach the paper filter to the funnel.
Note: keep this assembling since you will need it in some experiments.
Can you separate water from sand? What’s the name given to the technique you’ve just used?
Explanation:
EXPERIMENT 2
Separating water and sand
What will you need?
Material included in the kit:
• Gloves
• Paper filter
• Funnel
• Wooden spatula
Steps:
• Large measuring cup
• Small measuring cup
• Test tube with lid
Extra material:
• Water • Sand
1. Using the small measuring cup, add 10 millilitres (ml) of water into the large measuring cup. Then, use the plastic spatula do add a spoon of sand and mix well with the wooden spatula.
2. Place the funnel with the filter, as indicated in experiment 1, in a test tube.
3. Pour the mixture (water and sand) into the funnel.
The paper filter retains sand, since the particles are larger than the holes in the filter. On the other hand, water passes through it freely. This way, sand gets stuck in the filter and the water passes to the test tube, clean. This process of separating mixtures is called filtration. In filtration, the suspended solid particles in a liquid are separated through a filter.
EXPERIMENT 3
Chromatography
What will you need?
Material included in the kit:
• Gloves
• Paper filter
Extra material:
• Coloured markers • Water
• Blotting paper (napkin)
Steps:
1. With the coloured markers, draw small dots creating circles on the paper filter, as shown in the image below.
2. Make a wrap with the blotting paper (or napkin) and wet its tip in water.
Put the tip of the wet paper in the centre of
See what happens to the different coloured dots you’ve made!
Explanation:
This process is called chromatography. This is a physico-chemical process of separating homogeneous mixtures. The separation of its compounds is possible as they present a different weight, mass and density.
In the case of a complex colour (secondary), it is possible with chromatography to decompose it in its primary colours. This happens because the ‘basic’ colours have different weights and as so they remain on the paper when the water can’t soak them anymore.
1.3. Diffusion
KNOWING MORE...
The capacity that substances have of moving on others is called diffusion. More so, we can say that the colouring’s diffusion is greater in water than in salted water.
EXTRA EXPERIMENT
Do water molecules really move? What will you need?
Material included in the kit:
• Gloves
• Red colouring
• Pasteur pipettes
• Large measuring cups
Extra material:
• Tap water, hot and cold
ATTENTION: ask an adult for help.
Steps:
1. Fill a large measuring cup with cold tap water.
2. Fill in another large measuring cup with the same amount of water, however this time, with hot water.
3. With the Pasteur pipettes, add a drop of red colouring in both large measuring cups, at the same time. Make sure you pour the exact number of drops in both cups and do not stir them.
What do you observe?
Explanation:
The colouring spreads in the water from both cups, but at different speeds. When the water is hot, the water molecules move quicker, which makes the colouring spread faster. In cold water, colouring will take longer to spread, as the water molecules movement isn’t as fast as in hot water.
3. With the Pasteur pipette add a drop of red colouring to each large measuring cup. Do not stir any mixture.
What do you observe? In which of the cups does the colouring move faster?
EXPERIMENT 4
Diffusion
What will you need?
Material included in the kit:
• Pasteur pipette
• Wooden spatula
• Gloves
• Red colouring
Extra material:
• Salt • Water • Tablespoon
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
The colouring moves faster in the cup that only contains water than in the cup with water and salt. After a while, both liquids from the cups get completely coloured.
Steps:
1. Fill the two large measuring cups with water.
2. In one of the large measuring cups add salt and mix with the wooden spatula, until you can’t dissolve it anymore, this is, prepare a saturated solution.
• Large measuring cups Water with salt Water
Even though it is not visible, water molecules are always in motion. When you put colouring in water, water molecules collide with colouring molecules, making them move too. This way, colouring and water will mix up completely and the liquid gets the colour of the dye.
The quicker water molecules move, the faster colouring molecules move too and more rapidly the liquid is all in the same colour. The colouring moves slower in water with salt because besides water molecules there are also salt molecules. These occupy space, complicating the motion of molecules in the solution. In this solution there are more molecules and less free space for them to move, which makes the movement slower.
1.4. Density
KNOWING MORE...
Density is a measure of matter. It helps us quantify the amount of matter, composed of atoms, molecules or ions, present in a certain volume of a substance. Substances less dense than water will float on it. Substances denser than water will sink in it.
3. Fill the bottle almost to the top with oil. Use a funnel to help you.
EXPERIMENT 5
Almost a lava lamp
What will you need?
Material included in the kit:
• Gloves
• Pasteur pipette
Extra material:
• Red colouring
• Funnel
• Salt • Water • Cooking oil
• Bottle with lid, empty and clean
Steps:
1. Pour water into the bottle until ¾ of its volume.
2. With the Pasteur pipette add some drops of red colouring to the water. Close the bottle with the lid and then shake it a little, to mix the water and the red colouring.
4. Let the mixture get separated.
5. Now, pour salt into the bottle with the plastic spatula.
What do you observe?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
Oil floats in water because a drop of oil is lighter than a drop of water with the same size. This means that oil is less dense than water.
Density relates the mass of a material with the volume it occupies.
Salt is heavier (denser) than water and so it stays at the bottom. In this experiment, when you add salt, blobs of oil get attached to the salt grains and sink. When the salt is dissolved, the oil rises to the top creating a (almost) lava lamp.
EXPERIMENT 6
Coloured cup
What will you need?
Material included in the kit:
• Gloves
• Small measuring cup
• Pasteur pipette
• Red colouring
• Large measuring cup
• Wooden spatula
Extra material:
• Tall cup or glass
• Water • Honey • Cooking oil
• Marker • 96% ethanol or commercial ethanol
ATTENTION: ask an adult for help.
Be careful, ethanol is easily lammable.
Steps:
1. With the small measuring cup, add 25 ml of water to a tall cup or glass.
2. Identify and mark the level of water.
3. Pour the water from the tall cup or glass into the large measuring cup.
4. Add honey to the tall cup or glass until reaching the level previously marked.
5. With the Pasteur pipette, pour 2 drops of red colouring in the large measuring cup. Stir the mixture of water with the colouring using the wooden spatula.
6. Pour the water (with the colouring) into the tall cup, on top of the honey.
7. With the small measuring cup, add 25 ml of oil to the tall cup or glass.
8. Pour, carefully and slowly, 25 ml of ethanol also into the bottle. Use again the small measuring cup to help you.
What do you observe?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
The substances you’ve used in this experiment have different densities. The four of them remain on top of each other without mixing. Honey stays at the bottom of the bottle, then the water, followed by oil and on the top the ethanol. Substances have different densities, some are denser than others. In other words, denser substances have more particles in the same volume than the less dense ones. This is why the denser ones always stay under the less dense substances. In this case, honey is the densest substance, followed by water and oil. Ethanol stays on top because it’s the less dense substance.
KNOWING MORE...
Substances can be acidic, alkaline or neutral. Through pH indicators, chemical substances (alkalis or weak acids) that originate colour changes, we can determine if we are in the presence of an acidic, alkaline or neutral substance. These indicators can be natural or synthetic. It is also common to use an indicator paper, called universal indicator. This paper allows to properly identify the pH values since they have well defined colours for each one.
EXPERIMENT 7
The pH of substances
What will you need?
Material included in the kit:
• Gloves
• Large measuring cups
• Sodium bicarbonate
• Pasteur pipette
• Wooden spatula
• pH test strips
Extra material:
• Lemon • Water
Steps:
Part I - making an acidic solution:
1. To get an acidic solution, squeeze the juice of half a lemon into a measuring cup.
2. Then, with the gloves on put a pH test strip in the liquid. You need to have the gloves to not contaminate the pH test strips.
What happens to the pH test strip?
Explanation:
The strip changes colour. Now it is yellow. Why did this happen? We introduced the pH test strip in an acidic solution causing the colour change.
Part II - preparing an alkaline solution:
1. To get an alkaline solution, put some sodium bicarbonate and water into the a clean large measuring cup. Use the plastic spatula to help you. Then, mix it well using the wooden spatula.
2. Then, with the gloves on put a pH test strip in the liquid.
Scientist, what happens now to the pH test strip?
3. With the Pasteur pipette, add some sodium bicarbonate solution to the acidic solution and observe the gradual change of colour in the pH test strip.
Tip: if you can’t see any change to the pH test strips, try do add more solute to your solutions.
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
The strip changes colour as you add sodium bicarbonate because sodium bicarbonate is a base and as you add it to the acid, you will neutralise the solution.
If you continue to add sodium bicarbonate, there will be a point where the pH indicator will turn green. At this point, you have turned an acidic solution into a alkaline solution.
EXPERIMENT 8
Coloured secret messages
What will you need?
Material included in the kit:
• Pasteur pipette
• Wooden spatulas
• Sodium bicarbonate
• Small measuring cups
• Gloves
Extra material:
• Red cabbage • Knife • Wooden spoon
• Large and wide container • Hot water
• Container with lid • Paintbrush • Lemon
• Cotton buds • Sheet of paper or cardboard
ATTENTION: ask an adult for help.
4. Remove the red cabbage pieces and save this indicator in a container with lid, so that you may use it in the next part of the experiment.
Observe the pH scale for the natural pH indicator!
ATTENTION: check the LIST OF SUBSTANCES provided on the initial pages of the book before starting this experiment. SUBSTANCES
Steps:
Part I - prepare a natural pH indicator:
1. Put hot water in a large and wide container
2. Ask an adult to cut the red cabbage in small parts and put them in hot water.
4. pH scale for the natural pH indicator.
DID YOU KNOW...
That there are several types of pH indicator, among them natural indicators and synthetic indicators?
Natural indicators are indicators which are obtained directly from nature. They are mainly caused by the proportion of natural pigments (anthocyanins and anthoxanthins) that they have.
3. Stir it with the wooden spoon for some minutes.
When placing red cabbage in hot water we are separating the anthocyanin from the red cabbage and dissolving it in water.
ATTENTION: save the liquid of this experiment for the following experiments. Keep out of the reach of small children and animals (and also food and drink).
Part II - write your secret messages:
1. Wet the tip of the cotton bud in the alkaline solution.
Prepare an alkaline solution: in the small measuring cup add a pinch of sodium bicarbonate and about 3 drops of water. Mix it well using the wooden spatula. 1x 3x
2. With the cotton bud soaked in the alkaline solution, write or draw your message on the sheet of paper.
3. Then wet the other cotton bud tip in the acidic solution.
Prepare an acidic solution: squeeze half lemon to a small measuring cup and add with the Pasteur pipette some drops of water.
4. With the cotton bud part soaked in the acidic solution, write or draw another message on the same sheet of paper you’ve used before.
5. Wait until the invisible paint is dry!
6. When it’s dry, wet the brush in the red cabbage indicator and pass it over your secret message!
Can you reveal the coloured messages?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
A pH indicator is a substance that presents different colours depending on the pH of a solution. In this experiment you used a natural pH indicator prepared with red cabbage. This way, if the solution is acidic in the presence of this indicator, it will show a colour between pink and red. On the other hand, an alkaline solution will show a colour between blue and green, as you can see in the image of the pH scale of this indicator. With this natural indicator you can reveal your secret messages in a colourful way!
1.6. Oxidation
KNOWING MORE...
Some substances when in contact with oxygen can oxidise. Although oxidation is defined as a more complex process, this is a simple way of defining it.
EXPERIMENT 9
Secret messages with lemon
What will you need?
Material included in the kit:
• Pasteur pipette
• Large measuring cup
• Gloves
Extra material:
• Lemon • Cotton bud • Sheet of paper or cardboard
• Hairdryer • Water
ATTENTION: ask an adult for help.
Steps:
1. Squeeze half a lemon into the large measuring cup.
2. With the Pasteur pipette, add some adrops of water to the lemon juice.
4. Write or draw a message on the sheet of paper.
3. Dip the cotton bud in the lemon juice.
5. Let the invisible paint dry.
6. To discover your secrete message use the hairdryer and bring it closer to the sheet of paper.
Observe the revealed message! Which colour is it?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
As you already know, lemon juice consists of citric acid. Citric acid, by the action of heat, suffers a chemical reaction of oxidation!
When heating the sheet of paper, the oxidation of the citric acid occurs and it weakens the paper. The place where you’ve written or have drawn your message burns easily and gets a brownish colour, revealing your secret message!
EXTRA EXPERIMENT
Why do cut apples turn brown?
What will you need?
Material included in the kit:
• Pasteur pipette
• Small measuring cup
• Gloves
Extra material:
• Apple • Knife • Cling film • Lemon juice
ATTENTION: ask an adult for help.
Steps:
1. Ask an adult to cut, without peeling, an apple in three parts.
2. Add 10 ml of lemon juice into a small measuring cup. Then, with the Pasteur pipette, add some drops of lemon juice to one of the apple parts. Leave other in open air and the last one wrapped in cling film.
Explanation:
The piece of apple in which you’ve put lemon juice will keep its original colour, such as also the part wrapped in cling film. However, the one in open air will turn brown. Many fruits get a darker colour when ripe. A great part of the ripening process of fruits is caused by the action of oxygen present in the air.
Scientist, did you know that it is due to an accelerated process of oxidation - corrosion - that the copper coins have verdigris?
3. After a few minutes see what happens to each apple parts.
What do you observe?
ATTENTION: when you finish the experiment throw away all used food.
KNOWING MORE...
Surface tension is a very important property, characteristic of a liquid’s surface, which allows it to resist to an exterior force. Due to this property, many objects can float on a liquid’s surface, even if denser than it.
EXPERIMENT 10 Colour explosion
What will you need?
Material included in the kit:
• Gloves
• Large measuring cup
• Red colouring
• Pasteur pipette
Extra material:
• Soup plate
• Milk • Toothpick
• Washing-up liquid
ATTENTION: ask an adult for help.
Steps:
1. Measure 100 ml of milk with the large measuring cup and then pour it into the soup plate.
2. With the Pasteur pipette add some drops of red colouring.
3. With the help of an adult, add some washing-up liquid into the small measuring cup. Then, dip the tip of the toothpick in the liquid. It must only have one drop.
4. Place the toothpick (with the drop of detergent) in the middle of a colouring spot.
Observe the colour explosion!
5. Keep repeating the step 4 and have fun with the colour explosions!
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
Milk is a liquid that consists of water, fat and proteins. When you put the red colouring at the surface, this doesn’t get mixed with the milk.
However, if you put the toothpick with detergent in the colouring spots, these spread and create a colour explosion!
This happens because the washing-up liquid will break the bonds between the milk fats and break the surface tension, mixing the milk fats and creating the colour patterns you see!
Surface tension happens because the milk molecules at the surface, suffer a great attraction amongst themselves.
Image 6. Milk’s surface tension.
Inside the liquid, all milk molecules suffer these same attraction forces, but in all directions.
The molecules at the surface suffer only the attraction from the molecules that are near and under, since over them there is only air.
As the number of molecules that are attracted is lower, there is a ‘compensation’: creating a greater attraction at the surface, forming a kind of film/layer. It’s to this property that we call surface tension.
KNOWING MORE...
Most solids in nature are crystalline, which means their atoms, molecules or ions are ordered geometrically in space. The order found in many solids contrasts with the disorder found in gases and liquids. When a solid does not have a crystalline structure, it is said to be amorphous. The compounds, bonded by ionic bonds, display an organised structure which is called crystals. Depending on their components and their internal structure, different substances form different crystals.
EXPERIMENT 11
What will you need?
Material included in the kit:
• Small measuring cup
• Gloves
• Pasteur pipette
• Large measuring cups
• Wooden spatula
Extra material:
• Sugar • Hot tape water • Container
ATTENTION: ask an adult for help.
Steps:
1. With the plastic spatula, place four portions of sugar in one of the small measuring cups. This will be cup A.
2. Fill the large measuring cup with hot water.
3. Quickly, and with the help of a Pasteur pipette, pour some hot water inside cup A and stir the sugar water solution. If it does not dissolve completely, add some more water until the sugar is completely dissolved.
4. Pour the solution in a safe container and leave it somewhere to rest for several days.
5. As time goes by, the water will evaporate and sugar crystals will start to appear in the bottom of the container.
SUPER SCIENTIST:
Repeat these steps with sea salt. This will be cup B. Do the crystals formed by both substances look alike?
Are the crystals equal for each of the substances?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
When you prepare a solution with hot water you can dissolve more salts than if the water was cold. To this solution we call saturated solution, that contains the maximum amount of solute in a certain volume of solvent, at a specific temperature. While the solution is cooling it will deposit the salts in excess, originating crystals.
Depending on their components and their internal structure, different substances form different crystals.
EXTRA EXPERIMENT
Stalagmites and stalactites
What will you need?
Material included in the kit:
• Gloves
• Large measuring cups
• Sodium bicarbonate
• Small measuring cup
Extra material:
• Hot water • Small tissue
• 3 Wool strings or twines • Plate
ATTENTION: ask an adult for help.
Steps:
1. Fill both large measuring cups with 20 ml of hot water. Use the small measuring cup to help you.
2. Using the plastic spatula, add sodium bicarbonate to both large measuring cups until you make saturated solutions.
Note: you must be able to make a saturated solution with 2 spoons of sodium bicarbonate in 20 ml of water.
2x
2x
A saturated solution is a solution that contains the maximum amount of solute in a certain volume of solvent, at a specific temperature.
3. Twist the small tissue. Tie its ends with twine, and also the middle of the tissue.
4. Place the tissue’s ends inside the cups with the solutions. The ends have to reach the bottom of the cups. If necessary, put the cups closer together.
5. Place the dish under the tissue in between the cups.
air spaces in the tissue. This process is called capillary action. The sodium bicarbonate is dragged by water and while water evaporates the sodium bicarbonate deposits in the centre, crystallising.
Scientist, if you run out of sodiumbicarbonate, do not worry!
You can find this reagent in any supermarket so you can keep making your fantastic chemistry experiments!
KNOWING MORE...
When certain chemical substances are mixed, a chemical reaction and the release of a gas (carbon dioxide) can occur.
Scientist, this gas is released while living beings are breathing and also in the fuel fossils (like gas).
6. Wait a few days.
What happened?
Explanation:
The saturated solution of sodium bicarbonate rises through the tissue and drops from the centre. The drops transform into hard pillars of sodium. One is formed from bottom to top (stalagmite) and the other from top to bottom (stalactite). Water moves through the rope created with the twine, as it fills in the
DID YOU KNOW...
That the carbon dioxide is responsible for the greenhouse effect?
The excess of production of this gas is due to Human activities.
EXPERIMENT 12 Foam column
What will you need?
Material included in the kit:
• Gloves
• Pasteur pipette
• Large measuring cup
• Red colouring
• Sodium bicarbonate
• Small measuring cups
Extra material:
• Vinegar • Washing-up liquid • Water
ATTENTION: ask an adult for help.
Steps:
1. Make a solution with 20 ml of vinegar and 5 ml of washing-up liquid in a small measuring cup. Ask an adult to help you.
2. If you want, add some drops of red colouring to the vinegar solution using a Pasteur pipette.
3. Prepare a solution of water and sodium bicarbonate (2 spoons, with the plastic spatula), with about 25 ml of water, in the other small measuring cup. Mix well with the wooden spatula.
2x
2x
4. Mix both solutions in the large measuring cup.
Scientist, what happens?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
It originates foam. Foam is produced by the release of carbon dioxide (CO2) from the washing-up liquid solution, when the vinegar’s acetic acid reacts with the sodium bicarbonate.
Sodium bicarbonate is a compound consisting of hydrogen, sodium, oxygen and carbon elements. When it is mixed with vinegar (water and acetic acid) a chemical reaction occurs:
Carbon and oxygen elements bond and originate a new gaseous compound, carbon dioxide.
EXPERIMENT 13
How to fill up a balloon without blowing
What will you need?
Material included in the kit:
• Gloves
• Funnel
Steps:
• Sodium bicarbonate
• Balloon
Extra material:
• Vinegar • 0.33 l Plastic bottle
1. Add some vinegar to the 0,33 l bottle until 1/4 of its volume.
2. With the plastic spatula, put 3 spoons of sodium bicarbonate inside the balloon. Use the funnel to help you.
3. Place the balloon on the bottle’s neck. Place it carefully, the sodium bicarbonate cannot fall inside the bottle.
ATTENTION: when you finish the experiment throw away all used food.
SUPER SCIENTIST:
You can repeat the experiment using different amounts of sodium bicarbonate and vinegar and see how it influences the pressure inside the balloon.
Explanation:
Vinegar reacts with sodium bicarbonate and forms a gas, carbon dioxide. While the gas is forming the pressure increases and the balloon is filled up.
If you have tried to change the concentrations of both liquids, you have seen that the greater they are, the higher is the production of gas. It’s this gas that allows you to fill in the balloon!
Scientist, let’s simulate the volcanic eruption?
4. Lift the balloon so that the sodium bicarbonate falls into the bottle.
See how the carbon dioxide produced fills in the balloon.
EXPERIMENT 14
Volcanic eruption
What will you need?
Material included in the kit:
• Gloves
• Wooden spatula
• Small measuring cup
• Sodium bicarbonate
• Red colouring
• Large measuring cup
• Pasteur pipette
Extra material:
• Vinegar • Wheat flour • Bowl
ATTENTION: ask an adult for help.
Steps:
1. Prepare the ‘lava’ in the small measuring cup: add with the plastic spatula 2 spoons of sodium bicarbonate.
2. Put vinegar in the other large measuring cup, until ¾ of its height. Then, with the plastic spatula add also 3 spoons of wheat flour.
3. Use the wooden spatula to mix the contents of the large measuring cup. This cup will be your volcano! Put it inside the bowl.
4. Use the Pasteur pipette and add to the large measuring cup, 2 drops of red colouring. Use again the wooden spatula to mix the content.
5. Add now the content of the small measuring cup into the volcano (large measuring cup).
Observe the volcanic eruption! Which chemical reaction happens in this eruption?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
Sodium bicarbonate reacts with acetic acid that is present in vinegar, releasing carbon dioxide. The wheat flour helps us to simulate the lava, since it makes it more viscous. However, this is not what happens inside a volcano. This experiment is only for you to observe a simulation of a volcanic eruption.
EXTRA EXPERIMENT
Foam with egg white
What will you need?
Material included in the kit:
• Gloves
• Small measuring cup
• Wooden spatula
• Red colouring
• Sodium bicarbonate
• Pasteur pipette
Extra material:
• Bowl • Plastic cup • Egg white
• Vinegar • Water
ATTENTION: ask an adult for help.
Steps:
1. Carefully, separate the egg white from the yolk.
4. With the plastic spatula, add 2 spoons of sodium bicarbonate to the cup. Mix with the wooden spatula.
5. With the Pasteur pipette add 3 drops of red colouring to the mixture.
2. Pour half the egg white in the plastic cup and place the cup in the bowl.
Scientist, ask an adult to cook the content of the egg so you can eat it after doing the experiments!
3. With the small measuring cup, measure 25 ml of water and put it in the plastic cup with the egg white.
6. Again with the small measuring cup, measure 25 ml of vinegar and pour it also into the cup.
What happens?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
The egg white isn’t only used to make delicious desserts. It can also be used to fixate the gas that is formed during an experiment.
When we add the vinegar, a great amount of coloured foam forms and overflows the cup. Sometimes, when turning the cup upside down, the foam doesn’t fall!
Do you know why?
The acid from the vinegar, called acetic acid, reacts with sodium bicarbonate, forming a gas called carbon dioxide. The gas gets ‘stuck’ in the egg white which causes the formation of a great amount of foam.
KNOWING MORE...
Osmosis is the process in which water moves from a less concentrated solution to a more concentrated one, through a semipermeable membrane. The concentration of a solution is the amount of solute present in a certain amount of solution.
Prepare the solutions:
1.10. Osmosis 1 hour
Water with salt - add 50 ml of water and with the plastic spatula add 2 spoons of salt; Water with vinegar – add 50 ml of water and 15 ml of vinegar.
2. Place a sheet of paper under each cup. Identify both cups with the name of the solution you are going to use.
EXPERIMENT 15
How jelly sweets behave when in the presence of different solutions
What will you need?
Material included in the kit:
• Gloves • Small measuring cups
• Large measuring cups
Extra material:
• Gummies • Vinegar • Water • Salt • Sheet of paper • Pencil
Steps:
1. Using the plastic spatula and a small measuring cup, start by preparing a solution of salt and a solution of vinegar. One in each large measuring cup.
3. Put a jelly sweet in each cup and wait about an hour.
4. Put in the small measuring cup only water and add to it a gummy. Wait to see the results.
1 hour
with salt Water with vinegar
Observe the results! What happens to the jelly sweets?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
Jelly sweets, as the name indicates, are mainly made of jelly. Both jelly and the solutions you’ve prepared are a mixture of water (solvent) with a substance dissolved (solute). In the cup with water, the jelly sweet increases it size. However, the jelly sweet that remained inside the salt solution, practically didn’t suffer any changes in size. This happened due to a phenomenon called osmosis. This phenomenon can be defined as the movement of water, from a less concentrated place to a more concentrated one.
sugar Selective semipermeable membrane
Passing of water from the less concentrated side of sugar to the higher concentrated side
lower concentration of sugar lower concentration of sugar higher concentration of water higher concentration of water
Osmosis isn’t influenced by the type of solute but by the number of particles in a solution. This way, through this process, water moves from the solution with less particles to the one that has more until reaching equilibrium. This balance is reached when two different solutions have the same number of dissolved particles. As so, when placing a jelly sweet inside only water, this will go inside the jelly sweet, making it grow. However, the more molecules exist in a solution where the jelly sweets are, the less amount of water will move to the inside of the jelly sweets! This way, in the salt and water solution the jelly sweet will not grow as in water. Vinegar, for example, is an acid. This way, it breaks the bonds between the jelly molecules, increasing their sizes but losing their original shape.
1.11. Fluids and solids that can be moulded EXTRA EXPERIMENT Solid or liquid
KNOWING MORE...
There are materials that due to their structure are easy to mould.
What will you need?
Material included in the kit:
• Gloves
• Large measuring cup
• Red colouring
• Pasteur pipette
• Wooden spatula
Extra material:
• Water • Cornflour
• Tablespoon • Bowl
Steps:
1. Put 5 tablespoons of cornflour in the bowl.
2. Fill in 25 ml of water in the large measuring cup.
3. With the Pasteur pipette, put two drops of red colouring in the cup with water.
4. With the wooden spatula, mix the water with the colouring.
5. Add the water to the bowl with cornflour.
6. Mix the water and the cornflour with your hands.
7. Touch the mixture it with your hands.
Tip: if it gets too dry, add more water using the Pasteur pipette; if it gets to liquid add a little bit more of cornflour. Does this mixture seem to be a solid or a liquid?
8. Place the mixture on the table and observe. And now, does it look like a solid or a liquid?
ATTENTION: when you finish the experiment throw away all used food.
Explanation:
When the mixture is removed from the basin it looks like a dry solid, however when it’s placed on a table it looks like it drains as a viscous liquid. This happens because cornflour contains starch. In the mixture of cornflour and water, the starch particles will occupy the empty spaces left between the water particles. This way, when we press and squeeze the mixture with our hands, the water and starch particles become close together and the mixture looks like a dry and hard solid. When we leave the mixture on the table, the starch and water particles become far away again and the mixture looks like a viscous liquid, that drains slowly over the table. This substance is called fluid, as it has the capacity to flow such as liquids!
1.12. Molecules
KNOWING MORE...
Atoms are the basic unit from which all substances and matter are formed. Atoms can bond by chemical bonds originating molecules. These can be simple (same atoms) or compound (different atoms).
EXTRA EXPERIMENT
Make fantastic molecules!
What will you need?
Material included in the kit:
• Gloves
Extra material:
• Modelling clay • Toothpicks
Tip: use a certain colour for each specific atom.
Steps:
1. Make small balls of modelling clay! These small balls will be your atoms! Make red and colourless atoms, this way you’ll have different atoms for your molecules! The toothpicks represent the chemical bonds that are established between the atoms of the molecule.
2. Follow the instructions to create the molecules! You may represent a simple bond with a toothpick, a double bond with two toothpicks and a triple bond with three toothpicks.
a) Water molecule (H2O)
What you will need:
• 2 Atoms of H
• 1 Atom of O
• 2 Simple bonds
Water is a natural resource vital for life in our planet. Water molecules consist of 2 hydrogen atoms and 1 of oxygen.
b) Oxygen molecule (O2)
What you will need:
• 2 Atoms of O
• 1 Double bond
Oxygen is a molecule that consists of two oxygen atoms bonded by a double bond. It’s a colourless and unscented gas, at room temperature, and is one of the main components of the terrestrial atmosphere.
c) Carbon dioxide molecule (CO2)
What you will need:
• 1 Atom of C
• 2 Atoms of O
• 2 Double bonds
11.
Carbon dioxide is, at room temperature, colourless and unscented gas. It consists of 2 oxygen atoms and one carbon atom. This compound is very important for plants and vegetables as it’s an essential part of the photosynthesis process.
d) Nitrogen molecule (N2)
What you will need:
• 2 Atoms of N
• 1 Triple bond
Nitrogen is the most abundant gas in the atmosphere of our planet (more than 70%). Nitrogen molecules consist of 2 nitrogen atoms bonded by a triple bond. It’s an inert gas (non reactive), colourless and unscented.
2. Quiz
1. The mixture of water and oil is:
a) Heterogeneous
b) Homogeneous
c) Colloidal
6. The chemical reaction that takes place between vinegar and sodium bicarbonate releases:
a) Oxygen
b) Methane
c) Carbon dioxide
2. The filtration process separates:
a) A solid from a solid
b) A solid from a liquid
c) None of the above
7. What phenomenon causes water to move from a place with a low concentration of solute to a place with a higher concentration?
a) Capillarity
b) Osmosis
c) Decantation
8. The water molecule is made up of:
a) 2 oxygen atoms and 1 hydrogen atom
b) 2 hydrogen atoms and 1 oxygen atom
c) 3 oxygen atoms
3. Water molecules move faster when the water is:
a) Cold
b) Warm
c) Hot
5. What type of solution is lemon juice?
a) Acidic
b) Basic
c) Neutral
9. What is the pH of a neutral substance?
a) More than 7
b) Less than 7
4. Complete: Ethanol has ______ the same density as water.
a) Less
b) More
c) The same
c) Equal to 7
10. An oxygen molecule is made up of:
a) More than 7
b) Less than 7
c) Equal to 7