The Keening Factory

By:

Plastic Cup Chicken Squawk

Dr. Butler UTB PBworks
http://hallogreen.pbworks.com/w/page/59436349/FrontPage

Materials:

• Plastic Cup
• Yarn and Paperclip
• Wet Paper Towel
• Plastic Straws

What to do: 

1. Tie on end of yarn to the middle of the paper clip
2. Push the other end of the yarn through the hole in the plastic cup and pull it through.
3. Get a piece of paper towel about the size of a dollar bill, then fold it once and get damp in the water.
4. Hold the cup firmly in one hand, and wrap the damp paper towel around the string near the cup. While you squeeze the string, pull down in short jerks so that the paper towel tightly slides along the string. You should hear a chicken sound. 

How/Why does this work?
This is an example of how a sounding board works. The vibrations from the string would be almost silent without the cup, but when you add the cup, it spreads the vibrations and amplifies them.

What to do: Plastic Straw Horn
1. Flatten one end
2. Cut the flattened end to a point
3. Blow hard through the pointed end to get sound.
4. Add straws to make different sounds.

 
Discussion Questions:
What are the properties of sound that make the experiments work?
Why do different lengths of straw make different sounds?
Does the string make a sound without the cup? Why or why not?