Science Bloggers for Students DonorsChoose Challenge

Tuesday, May 20, 2008

Make your own model Landfill

Yesterday, I introduced you to landfills and how they are made. As trash breaks down a dangerous byproduct is produced - leacheate. Landfills not only must take care of trash, but it also must not pose other health and environmental threats, too.

Here is how a typical landfill is constructed.



So, a landfill must not let the liquid contaminants seep into the ground water or soil. Therefore, all landfills must be lined with either plastic or clay to prevent leachate pollution.

But which landfill liner is better? Which will successfully prevent leachate pollution? Clay or plastic?

Here's an activity you could do at home or with your youth group.

Supply List:
  • transparent 2-liter soda bottles cut in half with cap
  • 1 bag each of sand, gravel, topsoil, clay dirt
  • plastic wrap
  • food coloring - red or blue or green
  • jug of water

Instructions:

  • tap 3 holes in the bottle cap.
  • replace the bottle cap on the bottle.
  • after cutting the bottle in half place the top half of the bottle, cap-side-down, inside of the bottom half of the bottle.
  • place your liner at the bottom. If plastic - lay it on the bottom and press flat. If clay, pack it down with your fingers.
  • randomly select any or all three of the soils - sand, gravel, topsoil and begin layering the soils. be sure to pack them with your fingers. Or use the materials recommended on the cards.
  • you can layer your soils as thick as you want and as few or many layers as you want.
  • when you're down constructing your land fill, add a few drops of food coloring to your jusg of water. The colored water represents leacheate.
  • pour the colored water into your landfill and watch how fast the water drains.


What happened? Did the leachate leak through?





Repeat the exercise and change your materials or do it with friends. What did others find? How do different landfills compare? Was using clay or a plastic liner the most effective way of preventing leachate pollution?

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