National Engineers Month

	Activities by Grade	K - 2		5 - 8
		3 - 4		9 - 12

Flinker

What's a Flinker?  It's something that doesn't float or sink but just "flinks" in the middle.

What you need:

• foam packing peanuts
• paper clips
• clear container that will hold water (like a soda bottle with the top cut off)

Directions:

1. Fill a clear container with water.
2. Place a foam packing peanut in the water.  What happens?
3. What can you do to make the peanut flink (neither float or sink)?  Here are some ideas"  Attach paper clips to your peanut.  Or change the shape of the peanut.
4. Experiment!  Keep changing the design of your Flinker until it flinks for 10 seconds.

More:

Try making a different object, like a small sponge or a penny, flink.  Predict what you think will happen.  Then test it!

Engineering Scoop:

When you put a foam peanut in water, the water "pushes up" on the peanut.  (This is called a buoyant force.)  At the same time, the weight of the peanut "pushes down" on the water.  If the "pushing down" force of the peanut is less than the "pushing up" force of the water, the peanut floats.  If the "pushing down" force of the peanut is more than the "pushing up" force of the water, the peanut sinks.  If both forces are exactly equal, the peanut flinks!  (It doesn't rise or sink in water.)

© 2001 WGBH Educational Foundation