K-3 : Lesson Plan #1
Decomposition

Objective:
The students will make predictions, make observations, and chart changes in materials.


Materials:

  • Bucket of soil or a space on the school grounds where items may be planted in the ground
  • Food scraps (i.e. pieces of bread, crackers, apples, lettuce…)
  • Items commonly thrown away, such as a plastic bag, Styrofoam cup, aluminum can, printer cartridge, etc.
  • Will They Change? Worksheet
    (Download Worksheet)

Procedure:

  1. Discuss where garbage goes. Most of it ends up in landfills. Discuss what a landfill is and how the earth can only handle so much garbage.
  2. Have the students brainstorm different items people throw in the garbage. Record their responses on the chalkboard or chart paper.
  3. Hold up the items from the materials' section that have been collected ahead of time. Add any of these to the list that have not been recorded.
  4. Pass out the Will They Change? Worksheet. Explain to the students that they will be creating and observing their own “landfill”. This landfill will be in the bucket of soil or out on the school grounds.
  5. On the worksheets, have the students draw a picture and label each item that is going to be buried in their landfill. They should then make a prediction of whether they think the item will change or not change if it is buried in the soil for 2 weeks. Define “change” as getting smaller, changing color, changing its shape. (Getting dirt on it should not qualify as a “change”.)
  6. Bury the items in the bucket or ground.
  7. Leave the items buried for 2 weeks.
  8. After 2 weeks, unearth the items. Have the students complete their worksheets by drawing pictures of what the items look like now and charting whether they have changed or not.
  9. Discuss how some of the items changed and broke down over time. This is called decomposition and is part of the cycle of life. Items which decompose will usually not harm the earth and can actually help support new life as fertilizer and food. However, the items that did not decompose take up space and can be harmful to the environment. Therefore, recycling these items is more earth friendly.