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Energy Conversion

Different forms of energy—such as electrical, chemical, and thermal energy—often change to other forms of energy.

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Poop to Power

Poop to Power 

Credit: Laura Guerin
Source: CK-12 Foundation
License: CC BY-NC 3.0

What’s a dog owner to do? You have to walk your dog, and your dog has to poop. Do you just scoop up the waste and throw it in the trash? What if there were a useful way to recycle dog poop? Guess what? There is!

News You Can Use

  • It was first developed in India and China to take advantage of livestock waste. It’s a device called a methane digester. What it actually digests is poop. Inside the digester, animal waste is used to produce methane gas.
  • Methane is a simple hydrocarbon that is the chief ingredient in natural gas. Like natural gas, methane can be burned to produce heat and light.
  • Credit: Project Morpheus
    Source: http://www.flickr.com/photos/morpheuslander/5601157189/
    License: CC BY-NC 3.0

    Liquid methane can be used with liquid oxygen as rocket fuel for specialized propulsion systems [Figure2]

  • Recently, an inventive artist from Boston, Massachusetts, devised a methane digester for a different type of waste: dog poop at a local dog park. The methane is burned in a street lamp that provides light in the park. You can get an introduction to the project by watching this video: http://www.youtube.com/watch?v=aBaGXXG_A_4 

What Do You Think?

At the links below, learn more about using dog poop to produce useful methane. Be sure to read the “How It Works” page at the first Web site. Then answer the following questions.

  1. How does a methane digester work?
  2. What typically happens to dog poop that is picked up and thrown in the trash? What environmental problem does this create?
  3. What two problems does the methane digester in the dog park help to solve?
  4. What energy conversion takes place when methane from the methane digester is burned?
  5. Why is it better to burn methane than to release it into the atmosphere? Doesn’t burning methane produce carbon dioxide, a greenhouse gas that contributes to global warming?
  6. Methane digesters are used all over the world. What are they used for?
  7. What do you think? How else might dog-poop methane be used?

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Image Attributions

  1. [1]^ Credit: Laura Guerin; Source: CK-12 Foundation; License: CC BY-NC 3.0
  2. [2]^ Credit: Project Morpheus; Source: http://www.flickr.com/photos/morpheuslander/5601157189/; License: CC BY-NC 3.0

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