Internet Version [Naruhodo no Mori] Vol. 8

by Yumiko Mori

Vol. 8 June 15th, 1995

A very very long straw

Home science experiments for mothers of elementary school children

Toshi: "Today I want you to answer to a quiz before we start this experiment."
Tae: "If I givea right answer, do you give me anything?"
Toshi: "Nothing. But you can drink nice juice."
Tae: "OK, I'll take your quiz."
Toshi: "Do you think you can drink this juice from upstairs through a very long straw?"
Tae: "I think I can. But I think I may have to swallow very hard."
Toshi: "How about you, Mom?"
Mom: "Well, I'm not sure. I think this is to do with air pressure. I know one atmosphere is equivalent to 10 meter (~33 feet) of water pressure. And, upstairs should be less than 5 meter (~16 feet) in height. Then you should be able to drink! Should be! Is it right?"
Toshi: "Yes. Maybe this question was too easy for Mom."
Tae: " Where is juice I can drink?"
Toshi: " Here it is. But you have to drink this juice from upstairs."
Tae: " Are we actually going to do this experiment now?"

<Later>
Toshi: " Tae, try harder! The juice you want is only 30 cm away from your mouth!"
Tae: (Breathing hard) " Oh, it's so hard! I can not keep swallowing anymore because you make me laugh, Toshi!"
Toshi: " Tae, the juice went down all the way to the bottom. Now it's my turn! I'll try."
Tae: " Toshi, you're doing very well. You're actually drinking the juice. Leave some juice for me."

The reason why you can drink juice from upstairs: After this experiment, my son and daughter asked me, "What does this experiment mean?" My children seemed to assume they can drink juice through a very long straw anytime. A fact is that it is definitely impossible to drink when the height is beyond 10 meter (~33 feet). An Italian scientist, Torriceli, invented Mercury barometer in order to measure atmospheric pressure, which is roughly equivalent to 10 meter tall of water. As higher position you try to drink juice from, less help is expected from the atmospheric pressure. That's the reason why it's hard to drink.

Materials:

a 5 meter (~17 feet ) long of air tube
juice
a large size cup

Methods:

More than 3 people should participate. Required time is about 15 minutes.
Wash the air tube prior to an experiment.
Place the juice into the cup.
Two people go upstairs and bring down one end of the tube. The 3rd person on the downstairs puts the end into the cup.
Game start! One of the 2 people on the upstairs starts drinking. You can bring the juice level easily until its height becomes 3 meter (10 feet) high. But it's going to become very harder!

If you want to make a break you should make sure to keep the tube closed by holding very tightly. Or the juice will go down to the bottom.
Don't make laugh while a person is swallowing.
It'll get harder as the juice level goes up. If you have difficulty, you may want to ask the person on the downstairs to raise the cup a little bit.
To change the turn, one of the two people on the upstairs go downstairs and exchange the positions. If you feel a 5 meter tube is too long, you may want to cut it by a short length. (Don't make it too short, you may not be able to do the experiments properly.) If you swallow too hard, you may start feeling some pains inside your mouth. Do not continue when you experience pain.

"Anyhow, let's try!"

Do you know anybody who attempt to drink juice from upstairs? Of course, you could guess an outcome from your past experience. But, the essence of science experiments is to testing your guess by yourself. It may be harder than your guess or may be easier. Something totally unexpected could happen, or you may discover new finding. I was absolutely wrong in this experiment. I thought it easy to drink juice from upstairs. I would like to share this fun experiment with you and hope you and your family can enjoy a nice surprise.

Author	Yumiko Mori (Zushi, Kanagawa, Japan)
Illustration	Mitsue Ogata
Translator	Akira Ishihara
HTML format	Muneo Kume