In Ms. Frobisher's Science class, they are holding a contest. She has a glass bottle, and a little bronze ball, the size of which is precisely the same as the hole in the bottle.
Ms. Frobisher is giving the student who can put the ball in the bottle, without breaking the glass or destroying the ball somehow, an iPOD.
In her room, there is a microwave, petroleum jelly, a stove, and a freezer.
Six of the seven students make unsuccessful attempts to accomplish this feat.
Now, the seventh student Gavin comes up to the bottle and the ball. He thinks of using one of the tools in Ms. Frobisher's room at his disposal and uses one (not the jelly as it was already proven to not work) and five hours later, gets the ball in the bottle and his free iPOD.
How did Gavin do it?
Gavin put both the glass bottle and the bronze ball in the freezer and waited for both to come to equilibrium temperature. Bronze has a significantly higher thermal expansion coefficient (about 17X10^-6/C) vs. glass (about 7X10^-7/C), so the colder temperature in the freezer will cause the ball to shrink more than the hole in the bottle neck, and the ball will have clearance to fall into the bottle.
This assumes that the ball and the bottle neck hole are "precisely the same size" at room temperature.
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Posted by Kenny M
on 2022-07-25 08:59:44 |
One way to do it (spoiler)
