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Why does steam, escaping from a hole in a metal tube, attached to an object, propel that object?
- Danny Jodoin (age 10)
Grande Prairie, Alberta
Steam is just water that has turned into a gas. The steam takes up
a lot more space than just water. When all that steam is stuck in a
tube, it tries to find a way out. As more and more water becomes steam,
the pressure in the tube gets higher. If there is something plugged in
a hole in the tube, the steam will push so hard that the object is shot
out. Once the object is gone, the steam can spread out everywhere. As
the steam is forced out in one direction, Newtons 3rd law says that an
equal force, in the opposite direction, is applied by the escaping
steam on whatever the object is...that's why it moves.
(republished on 08/02/06)
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