Biodegradable and Non-biodegradable Materials

    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.
 Biodegradable and Non-biodegradable Materials
                                                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.

   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.
Fresh milk
Sour milk
     Physical state
Unused plastic bags
Used plastic bags
 Physical state
·         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.
Names of things
Animals dung
                                                   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.
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.

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