Unit 6: Water Flowing Around Us
Building a terrarium activity guide and handout
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Unit 6: Water flowing around us
Building a terrarium activity guide
Estimated duration: 45 minutes Aim • •
To create a terrarium as a model of the water cycle To describe the stages of the water cycle
Outcome By the end of this class, students will be able to: • better follow instructions for model construction • understand the requirements for pot plants • understand the water cycle • be more confident in their scientific literacy in relation to the water cycle
Resources • • •
Water catchments slideshow Building a terrarium student handout Resources to make the terrarium: You will need sufficient quantities to make a number of terrariums in small groups. Each group will need • a large plastic drink bottle (2Lor 1.25L) with a lid • potting mix • small house plants or seedlings (ask your local nursery for plant ideas) • a Stanley knife • tape • water
Activity Description A terrarium is a sealed glass or plastic container used for growing plants that require a high level of humidity. The idea is to demonstrate the water cycle in miniature form via the terrarium. Remind students about the water cycle. Use the diagram in the slideshow to reinforce the concept of the water cycle and to reinforce the scientific terms. This is fully explained in the water cycle activity guide earlier in this unit. Have the materials ready for the students and remind them of the safety requirements when using sharp knives. Divide student into groups and have them
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begin constructing their model terrarium. Instructions are provided on the student handout and also below: 1. Use the Stanley knife to cut the bottom of the soft drink bottle, 5‐6 cm from the end.
2. Put soil in the bottom to a depth of about 4 cm. 3. Remove a seedling from their pot and carefully place them into the soil in the bottle. 4. Re‐seal the end of the bottle with tape by replacing the end portion. 5. Water the soil by removing the bottle cap. 6. Replace the cap and place it in a sunny location. 7. Make observations of the terrarium over the remainder of the day, or ideally over the following few days. 8. You can open the terrarium to check if the air inside is hotter or colder/ dryer or wetter then outside the terrarium. Note: ensure that plants are not drowned with too much water. They should not be place in direct sunlight all day as the sealed container will heat up in the sun and can become too hot depending on the plant type. Get students draw annotated diagrams of the terrarium and how they think it will illustrate the water cycle. They should include a description of how their terrarium is a model for these processes: Terms Possible answers Precipitation water you add Absorption water absorbed by soil Transpiration water transpired by plant Condensation, clouds condensation on bottle sides Sun putting it in a sunny spot Run‐off, underground water excess water at bottom of terrarium if you add too much Rivers, streams and oceans as above Ideally students would confirm their guesses over the following few days, as the terrarium starts to cycle water, and would then present a final annotated diagram. If leaving the terrariums for a number of days isn’t an option, you might want to run this activity at the start of the class or the day and then see what the terrariums have
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done at the end. However you will need a sunny window, or possibly a heat lamp, or you might find that the water hasn’t condensed at the top of the terrarium, and so that it hasn’t worked as an illustration of the water cycle. Extension activities Get the students to visit the local primary school or a junior secondary class and conduct a lesson on the water cycle. Run a session on terrarium making to help them understand the ideas. Imagine life inside a bottle (i.e. a metaphor for the earth). If you planted a garden in with you, you would survive for a long time. Explain if it would be possible to survive inside this terrarium. What would you have to deal with to survive long term?
Student Roles and Responsibilities Participate in agreed tasks Contribute to class discussions Complete activities and worksheets Work cooperatively with others Seek teacher assistance and support when needed
Level of Teacher Support Facilitate discussion Organise materials and equipment Provide encouragement Introduce tasks and activities Provide assistance when requested
Assessment To use this learning activity as an assessment task, collect evidence such as : Teacher checklist and observation Student research notes and report Copies of student materials and worksheets Completed model Photos or videos
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Unit 6: Water Flowing Around Us
Building a terrarium student handout The water cycle is the path that water travels through, beginning as rain or snow, then travelling down rivers and streams into the oceans to be evaporated to become clouds and then rain again. In the process, the precious liquid H20 is absorbed by living things that need freshwater to survive. The amazing thing is that the freshwater that we drink is only about 1% of the total water available on the planet and that this amount remains fairly constant, even though it changes state from liquid to gas and sometimes freezes into ice and snow. Most of the water on the planet (97%) is found as saltwater in the seas and oceans. A further 2 % is trapped as ice and snow. It is amazing to think that our water system is one large recycling system. The water molecules that have passed through your body have been recycled through all the living things that live and have ever lived. Just think, one of the molecules in your body right now could have passed though the body of an ant, a dinosaur, Julius Caesar or Florence Nightingale!
Building a Terrarium A terrarium is a miniature ecosystem, like the earth. Once you create your ecosystem you should be able to walk away and it will look after itself. The water cycle will operate independently inside the system, passing through different stages and states so you won’t need to keep adding water. What you need • • • • • •
Large plastic drink bottle (2L) with lid Potting mix Small house plants and seedlings Stanley knife Tape Water
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Unit 6: Water Flowing Around Us
Building a terrarium student handout, p.2 What to do 1. Use the Stanley knife to cut the bottom of the soft drink bottle, 5‐6 cm from the end. 2. Put soil in the bottom to a depth of about 4 cm. 3. Remove the seedling from their pots and carefully place them into the soil in the bottle. 4. Re‐seal the end of the bottle with tape by replacing the end portion. 5. Water the soil by removing the bottle cap. 6. Replace the cap and place it in a sunny location. When you have made your model, you need to be able to communicate the ideas to others. Write a summary paragraph of how you think the terrarium will work as a model ecosystem Draw a diagram of the terrarium and how you think it will illustrate the water cycle as it occurs in water catchments. Include the terms: precipitation, absorption, transpiration, condensation, sun, run‐off, rivers and streams, clouds, oceans.
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