My lunch leftovers

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Students compost their food scraps and share ideas about how food waste breaks down into

My lunch leftovers

Key Concepts: Using senses, composting, soil

Materials: Empty compost bags (e.g. brown paper)
and bins

Print & Copy:
My Lunch Leftovers (one per student)


Set up compost bags and/or bins where students can place their food scraps at the end
of lunch.


  1. Model how to fill in the My Lunch Leftovers worksheet.
  2. Show students how to put peels and cores into compost bags (or bins).
  3. Show students how much compost there is at the end of lunch (e.g. count the bags, weigh
    the bags, estimate the volume).
  4. Fill in the Why Waste Food survey to catalogue the variety of reasons why students are
    throwing out lunch foods.

Discussion Questions

Choose one or several of the questions below.


  • What are some new ideas you have about lunch as a result of this audit?
  • What do you think your parents or guardians would say if you threw all your food into the compost bin? Why would they say it?
  • Why is the compost bin a better spot for food scraps than the garbage bin?
  • How would you estimate the amount of food scraps from your class in a week?


  • We can use compost to make good soil but it cannot have any wrappers in it. Why do you think wrappers ruin compost?
  • What do you think happens when food scraps rot?
  • How do you think food scraps break down into compost or soil?
  • If you look closely at soil, what do you think you will find?
  • What do you think would happen if we put some worms into the compost?

Follow-up: Field Trip

  • Arrange a tour (or virtual tour) to a waste resource management site to see how composting works in your community.
  • Arrange a guest speaker to demonstrate vermiculture (worm composting) for the classroom.


Kracl, C., & Harshbarger, D. (2017). Methods & Strategies: Ask the Right Question. Science and Children. 54(9), 78-82.

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