This Week's Experiment - #322 Stomping Insects
Don't worry about the title of this week's experiment. We will not squash
any insects. They will do the stomping. We are just going to listen to
their tiny footsteps. You will need:
an umbrella
some shrubs or bushes
A thin plastic cup or a paper cup
wax paper
a rubber band
First we need an insect. If you happen to have one nearby, you can use it.
If you don't, you can use the umbrella to collect one, as we did last week.
Open the umbrella and hold it upside down under a bush or tree limb. Give
the bush a good shake and you should see several insects fall into the
umbrella.
Look at the insects and pick one that looks interesting. We will be
listening to their footsteps, so don't start with a tiny one, unless it has
really big feet. Carefully scoop the insect you have selected into the cup.
Place a piece of waxed paper or aluminum foil across the top of the cup and
secure it with a rubber band or some tape.
Now we are ready to listen. Move to a quiet room. Place the bottom of the
cup against your ear and listen carefully. If the insect is walking around,
you should be able to hear its footsteps.
How can you hear the footsteps of such a tiny creature? To find out, go to
the kitchen. Lean over and tap your finger on the floor. Listen carefully
to the sound it makes. Open the cabinet and take out a box of cookies.
Tap on the side of the box. This time the sound is much louder. The floor
is stiff and solid. When you tap it, it does not vibrate much. The cookie
box is much more flexible. Your tap causes it to vibrate back and forth.
That causes the air around the box to vibrate. These vibrations in the air
are what you hear as sound.
The insect walking on the cup causes it to vibrate, just as the cookie box
did. When the side of the cup vibrates, it causes the air inside the cup to
vibrate too. As the sound bounces around inside the cup, it soon has the
entire cup vibrating. By placing the bottom of the cup against your ear,
these intensified vibrations go straight to your eardrum, letting you hear
the sound of an insect's footstep.
When you are done, be sure to release the insect, eat the cookies, and put
everything away. Otherwise, you won't need the cup to hear the sound of
someone telling you to come and clean up this mess!
Have a wonderful week.
From Robert Krampf's Science Education Company
PO Box 60982
Jacksonville, FL 32236-0982
904-388-6381
krampf@aol.com
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