Story 10. Tin Can And Science
Billy and his friend Jane have been learning about sound in their science class.
So far, they learned that sound is a vibration.
Someone speaks, the sound travels to us, and we hear it.
Sound vibrations travel on air.
They also discovered that sound vibrations can travel on wires. Their science teacher, Mr. Green, likes to explain the theories behind science.
He also thinks it's important to see science in action.
Mr. Green suggested they try a simple sound experiment.
He told his two students all they needed for their scientific demonstration was some string, about five metres, two tin cans, and two paper clips. Make sure there are no sharp edges on the cans, their teacher cautioned.
First, you make a small hole in the bottom of each of the tin cans.
Then take one end of the string and pass it through the hole in one of the cans.
Wrap that end around the paperclip and tie a big knot so that the string cannot slip out through the hole.
Do the same thing with the other can.
When everything is assembled, each of you take a can and walk away from each other until the string is very tight.
One of you put the tin can up to your ear. You are the listener.
The other speaks into his can.
The listener should easily be able to hear what the speaker is saying.
Billy and Jane found the materials they needed and did exactly as Mr. Green had explained. They put everything together and then tried it out.
First, Jane spoke into the can.
She said, Billy, can you hear me?
Her friend answered back right away.
That's amazing, she said quietly.
I can really hear you clearly.
I can almost feel the sound vibrations coming down the string.
The next day, Mr. Green asked them what they had learned.
That's easy, said Jane.
Our voices are vibrations.
We speak into the can and it vibrates.
The vibrations can makes the string vibrate too.
When the vibrations reach the can at the other end, they make the can and the air vibrate.
That's why my friend could hear me.
Try it sometime.
Science really is fun.
