# eli5 can something be hot and cold at the same time?

37 views
0

I know cold and heat contradict themselves, but really it’s just a matter of how fast each atom is moving to find the heat. So if there is a checker pattern of low energy and high energy atoms, could something be both hot and cold? And if so, are there any real world examples of that?

In: 0

No. The temperature of an object is determined by the *average* kinetic energy of its particles within the object’s rest frame. Your ‘checkerboard’ object would have a temperature halfway between that of the fast atoms and the slow atoms, and the ‘checkerboard’ itself would only last a fraction of a second before the atoms’ velocities became randomized again through transfer of energy.

Yeah, take a hot pocket and microwave it for the recommended amount of time. The outside is piping hot but the inside is still cold af

The “checker for high and low energy atoms ” is Maxwell’s Demon https://en.m.wikipedia.org/wiki/Maxwell%27s_demon and is one of the core thought experiments for physics. (Edit I misread checker as a verb….but the point stands)

Within an object all at one temperature, there will be atoms of many energies, but temperature is a function of the collection.

If we think about one object having multiple temperatures, like me having cold hands but normal body temperature, we are implicitly splitting the atoms into two collections.

You could easily make a surface that feels hot and cold in a checkerboard pattern. Make alternating squares of metal and styrofoam, and when you touch this, the metal surfaces will keep conducting heat away from your skin, while the styrofoam surfaces will quickly reach the temperature the skin.