How can we change temperature without adding or removing heat? Are other form of energies added to the body to increase it's temperature?
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2$\begingroup$ You can send a current through it. $\endgroup$– my2ctsCommented Sep 19 at 12:09
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2$\begingroup$ you can expand/contract it, send current through it, shoot objects at it. $\endgroup$– Amit VermaCommented Sep 19 at 12:17
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2$\begingroup$ This question is similar to: Relationship between heat and temperature. If you believe it’s different, please edit the question, make it clear how it’s different and/or how the answers on that question are not helpful for your problem. $\endgroup$– BioPhysicistCommented Sep 19 at 12:18
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$\begingroup$ Related: en.wikipedia.org/wiki/Magnetic_refrigeration $\endgroup$– PM 2RingCommented Sep 19 at 12:49
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$\begingroup$ Isn't adiabatic heating and cooling just that? Temp changes, entropy doesn't? $\endgroup$– JEBCommented Sep 19 at 12:54
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3 Answers
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The two most efficient ways are probably the ones that made it into the kitchen. Induction cooking uses induces current in the bottom of a cooking pan. Ohmic dissipation then delivers heat. A microwave oven heats up water in a body of food. You could bombard the body with photons, protons or electrons or other particles. All of these methods deliver energy that is then (partly) converted into heat. Of course, you can also use a chemical reaction such as is done in some types of hand warmers.
For cooling you could use Peltier cooling. Devices based on this effect are commercially available. Laser cooling is used to cool gases to ultralow temperatures.
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When it is winter have you never rubbed your hands together?
Work done against the frictional forces present will increase the mean kinetic energy of the molecules which make up you hand which you sense as an increase in temperature.
Compressing a gas can raise its temperature (whereas expansion can lower the temperature), passing an electric current through a wire can raise its temperature, shining light onto an object can raise its temperature, sound waves can raise the temperature of an object (a little), radiation emitted as a result of nuclear decay can raise the temperature of an object, etc.
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Statistical physics/thermodynamics distinguishes two ways of changing the energy: via work (i.e., due to variation of macroscopic external variables) and via heat (i.e., by transferring energy on microscopic level, e.g., via molecular collisions.) Thus, we can change the temperature by performing work, without transferring any heat.
