I know that it does but how is it possible, given that mass and gravity are what gives an object weight, that heating an object up will increase its weight?
I know that it does but how is it possible, given that mass and gravity are what gives an object weight, that heating an object up will increase its weight?
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On paper, it doesn’t. In practice, heating an object can change how its weight measures. Normally it won’t, though.
For instance, heating steel wool causes it to burn, trapping oxygen from the air and so adding more material – more mass.
Heating a burger will dry it out and char it, driving off water and hydrocarbons, reducing its weight.
Then you’ve got gases, which expand when heated, and if surrounded by other (not-heated) gas this can cause a buoyant force that offsets their weight.
Heating an object will not increase its weight. Weight is the force an object with mass experiences when put in a gravitational potential.
Heating an object will cause it to expand, so strong manning your point, if you have a rod of a very heat expansive material, and you place it vertically next to a very steep gravitational potential, for example, a small black hole, it would increase the weight. As more of the metal is closer to the centre of the potential. Although, the other end would also expand. I’m sure you could conceive of a way to set this up.
However, because gravitational objects other than a black holes or neutron stars are so large, this would be beyond negligible.
The only way heating something could increase mass is via introduction of new material to the structure. Most likely, as the sample heats up, atmospheric molecules get added to the sample and binds to the sample.