30 Apr 2012

With all the IPL going - here is a spinning Ping Pong Ball

A fairly safe cryogenic reaction engine.
https://www.instructables.com/id/10000-rpm-ping-pong-ball/
6 years ago


Just wondering what makes the ball spin?
Harshad Italiya

Harshad Italiya

Electronics and Communication
6 years ago
The_Big_K


Just wondering what makes the ball spin?
Some chemical trick ! Not sure . 😕
6 years ago
godfather
Some chemical trick ! Not sure . 😕
Never took interest in Chemistry. 👎
manishks

manishks

Branch Unspecified
6 years ago
We can convert a ping pong ball into a hero's engine by poking two holes tangentially to surface of ball. Then drop it into a liquid nitrogen and hold it under surface for few seconds. As air in ball cools pressure in ball drops and some liquid nitrogen is forced into ball due to atmospheric pressure. Now take the ball out and put it on table. As nitrogen boils and discharge ball spins rapidly!!
ISHAN TOPRE

ISHAN TOPRE

Branch Unspecified
6 years ago
The spinning is rather simple and there is no black magic as someone may suggest.

The spinning is because of boiling Nitrogen. If you observe the video closely the ball has holes in it. In normal condition, the volume in the ball is occupied by atmospheric air. Now when you dip it in Liquid Nitrogen and take it out, the volume is partially filled by Nitrogen. The N2 boils and it shoots out of the holes thus we get spinning.

The important thing to not is that, at how much volume of liquid N2 are we getting 10,000RPM. It will last how much time and if applied in some weight carrying operations (like automobiles/ robots), what will be its payload capacity?

Also, this demonstration reminds me a lot of Ajeet.
His famous dialog,

[​IMG]

Liquid isse jine nahi dega aur Oxygen isse marne nahi dega
Translation: Liquid will not let him live and Oxygen will not let him die.
😨
6 years ago
manishks is right as also issue. liquid nitrogen gets into the ball through a hole pricked in the ball. However, the hole should be as tangential as possible. After that the behaviour is rather trivial. It is rocket science (at a very basic level). Dr.Kalaam will turn up his nose at it.

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