Students’ Learning Outcomes
Differentiate between biodegradable and non-biodegradable materials
Information for Teachers
· Bio-means life and degradable means breakable.
· The things are actually broken down by microorganisms i. e. fungi and bacteria into simpler things. Such things are called biodegradable e. g. food items (fruit, vegetables, grains, flour, bread), paper, cloths dead bodies etc.
· The things which are not breakable by microorganisms into simpler things are called non-biodegradable e. g. shopping bags, plastics, rubber, things made of glass and wood etc.
Material / Resources
Fresh milk, sour milk, used and unused plastic bags and textbook
Worm up Activity
Ask the students following questions and write their responses on board:
· Why does milk get spoiled?
· Explain the concept of decomposition. Inform the students that there are things around us which are made up of easily degradable materials while others last for thousands of years without any significant decomposition.
· Flesh in dead bodies decomposes very early whereas skeleton (bones) remains intact for many years.
Development
Activity 1
· Divide the students into two groups.
· Give the following materials:
Group 1: fresh milk, sour milk
Group 2: used plastic bags 7 unused plastic bags
· Draw following table on board and ask students to record their observations. Now write the students’ responses on the board.
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Fresh milk
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Sour milk
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Differences
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Color
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Smell
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Physical state
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Unused plastic bags
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Used plastic bags
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differences
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Color
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Smell
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Physical state
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· Conclude this activity by explaining that differences in smell, colour and physical state of milk indicate that it is a biodegradable material while smell and colour of plastic bags didn’t change after use. So it is a non-biodegradable material.
Activity 2
· Draw the following table on the board and ask students to copy it in their notebooks.
· Ask the students to compare the items by writing Yes or No in the column of the table according to
correct category.
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Names of things
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Biodegradable
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Non-biodegradable.
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Bread
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Rubber
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Birds
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Sand
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Rice
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Meat
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Glass
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Stones
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Animals dung
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Sum up / Conclusion
· Revise the learning of biodegradable and non-biodegradable materials.
· The things which are broken down by microorganisms into simpler things are called biodegradable while the things which are not breakable by microorganisms into simpler things are called non-biodegradable.
· Involve the students in solving the questions given at the end of chapter / unit in textbook.
Assessment
Ask students to answer the following questions:
· Name some materials from daily life which don’t rot.
· Does a plastic toy get rotten when left in open air for a few days?
· Why it is advised to bury dead bodies of animals and the peels of vegetables in soil?
· What are the advantages of keeping the biodegradable and non-biodegradable items present in the garbage separate?
· What can be done with the materials that can’t be broken down easily
Follow up
Ask the students to perform the following activity at their homes:
· Take two jam bottles or plastic bottles and label them “A” and “B” and fill them with some mud.
· Put a piece of bread in bottle and a piece of plastic toy material in bottle B.
· Leave the bottles in open air and observe after 3 days which material is decomposing.
· Record the observations and write conclusion of above activity in your notebook.
