Internet Version [Naruhodo no Mori] Vol.50

by Yumiko Mori

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Vol.50   March 15th, 2000

Air-Pumped Jack

Home science experiments for mothers of elementary school children

Mom: "Can someone stand up here?"
Mom has placed a cardboard sheet first, then put a plastic trash bag and a plastic board on the top of it.
Kotani: "OK, I will stand there!"
Mom: "I will start blowing air to lift Kotani up."
Mom start blowing air into the trash bag through a straw.
Wakayama: "I think you can not lift him."
Takeda: "He is too heavy!"
Hirose: "Look! The bag is going to break apart!"
The bag is completely swollen and the plastic board is bent backward. But Kotani is not lifted at all.
Mom: "No, this doesn't work. Well, we can try the alternative way."
Mom decides to use a wood board instead.
Mom: "Kotani, can you stand on this board?"

Wakayama: "I think it's impossible to lift a human body."
Kotani sits on the wood board.
Mom: "OK, I am going to start lifting you."
Mom blows air into the trash bag through a straw. Gradually the bag is getting more swollen.
Wakayama: "Oh, Kotani is lifted up."
Hirose: "Amazing!"
Mom: "Why does this work better on a wood board?"
Takeda: "Because the board has more area."
Mom: "Then why does it work on a large area?"
No one can answer to this question.
Mom: "Apparently, it is possible to lift a car tire by blowing air into a bag."
All the students can't believe that's possible.
Kotani: "I wonder you can lift yourself by blowing air into a bag while you sits on it. "
Mom: "Maybe you can. That must be uplifting experience."

Materials

A sturdy wood board (i.e. drawing board)

A big trash bag

A bendable straw

A large cardboard sheet

A packing tape

A pair of scissors

How to make a jack

1. Cut a big trash bag so it fits to the wood board.
   

2. Insert a straw into one end of the trash bag.

3. Seal the trash bag around the edge with a packing tape, so air inside the bag won't leak out.
   

4. First, place a cardboard sheet on the floor. Put the prepared trash bag on top of the cardboard sheet.
   Finally put the wood board on the top.

5. Someone sits on the board. He / she should sit at the center of the board.
   

6. Blow air into the trash bag through the straw.
   
   

* Air may leak out from the site where the straw was inserted.
Make sure to seal the site completely.

* Use a more sturdy board if you want to lift a heavier load.
Find out how you can lift a car by blowing air.

Integrated Force from large area

Even if it is weak force, when force is integrated over a large area, the force can become strong enough to lift a heavy load. Recently we had a parent teacher association meeting. Many activities were reported in the meeting. Even though I was not aware, many other people voluntarily worked to make these events successful. If more people join, even more significant goal can be achieved. Sad thing is many people think their efforts alone can not change society or neighborhood.