Would violently shaking something cause a temperature change? For example, if a container of water was shook violently enough; would it be possible to make it boil?
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1$\begingroup$ Possible duplicates: physics.stackexchange.com/q/413097/2451 and links therein. $\endgroup$– Qmechanic ♦Commented Oct 2 at 9:09
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2 Answers
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Actually, that's exactly what James P. Joule demonstrated in 1845: the Mechanical Equivalent of Heat. He used brass paddles to mix a barrel of water. He found a direct relationship between his calculated amount of work and measured temperature.
Boiling point is highly improbable. For a simply detectable change, Oocities.org reckons: 'The amount of heat needed to raise a pound of water (0.45 kg) by one Fahrenheit degree [or Celsius, same scale] is equivalent to raising the water 778 feet (237 m) — about as high as the Eiffel Tower in Paris, 80 stories up.'(http://www.oocities.org/~gaiachurch/fasinata.html)
With his experiment, Joule proved that the mechanical energy that is exerted by the sides of the bottle on the water increases the average movement (kinetic energy) of the water molecules. The longer/faster the bottle is shaken, the warmer the temperature. Joule thus proved Conservation of Energy...
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$\begingroup$ See what I did there. Used the Eiffel Tower as an honorary example on its 126th anniversary. Haha $\endgroup$– TxaCommented Mar 31, 2015 at 13:43
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Yes, you will definitely increase the temperature of the water.
Lets say that we increase the speed of the container, with an amount of energy of 1kJ.
If we stop the container (does't matter if we do it suddenly or progressively), the 1kJ speed energy will be converted to heat, both to the water inside and to the device used to stop it (e.g. a wall or our hands). The amount of heat energy that receive the water depends on the materials, the geometry and so on.
But it would be quite difficult to make the water boil by only shooking it because the water and the box will probably lose their heat energy by convection, conduction and radiation to the air of the room before boiling.
