Internet Version [Naruhodo no Mori] Vol.48

by Yumiko Mori

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Vol.48   November 15th, 1999

Boomerang

Home science experiments for mothers of elementary school children

Satoshi: "I like here.."
Mom: "I made different types of boomerangs. Which one do you want to try?"
Satoshi: "I take this one. Ren, take one you want."
Ren: "I like this one."
Both Satoshi and Ren have chosen a 3 wing type boomerang.
Mom: "Satoshi, that one is difficult to throw. You need to throw very well. Otherwise it doesn't come back. Try this instead. This boomerang is easy to throw. Look!"
Mom puts a boomerang on a picture book and hits the boomerang with a stick.
It flies off as it spins itself, makes a big turn, and comes back to Mom's foot.
Mom: "Look! It came back to me."
Satoshi: "Mine should come back too. Watch!"
When Satoshi throws his boomerang, it flies off and has landed on a big tree.

Ren: "No! It has landed on tree."
Satoshi: "Don't worry. Mom can go up to get it."
Ren: "I am going to throw. Can you watch?"
Ren throws well. He nearly caught his boomerang.
Satoshi: "I will try again."
Satoshi starts chasing the boomerang he has just thrown.
Mom: "Satoshi, don't chase boomerang."

Materials

Used postcards (or similar thick paper)

A pair of scissors

Scotch tape

Chop sticks (or pencils)

A picture book for children (each page is made of thick layered paper)

How to make boomerangs

1. Fold a used postcard in halves and cut it along the folded line.

2. Fold each of the cut parts in halves again.

3. Put the two parts together as illustrated. Reshape the corner into a rounded corner.

4. Secure the assembled parts with pieces of Scotch tape.
   Now, this boomerang is ready to throw.

   

How to fly boomerangs

5. Open a picture book and hold it with your left hand.

6. Place a boomerang on the picture book as illustrated.

7. Hit the boomerang toward the front with a chopstick.

   

Children don't try solving puzzles

A boomerang flies off in the air while it spins itself, but it makes U-turn and comes back. I wonder why boomerangs come back. It's very interesting. I have realized the earth is circling around the sun, as it spins itself. It is just like a spinning top. I am not sure whether mechanical dynamic of boomerangs is related to that of the earth. Hoping to motivate my children, I tend to ask them how and why it works. But even though I don't understand difficult physics theory, the earth still keeps rotating. By the same token, just enjoy throwing your own boomerangs.