Lets say i have several baseballs, one is at 0 degrees Celsius, another at absolute zero, another at 100 Celsius and one at the Planck Temperature.
Will they weigh different amounts? My WAG is they do because of the different amount of movements, i really have no idea though.
For 0 Kelvins, 0 C and 100 C, there’s a theoretical difference in weight (because the molecules are moving faster at higher temperatures, giving a relatavistic increase in mass), but it’s way way too small to measure.
At the Planck temperature, then there’s definitely more mass, but of course it wouldn’t be a baseball anymore, and I’m not sure that the concept of temperature is even very applicable.
Another point is that a colder baseball has a slightly smaller volume, and so will weigh more when placed on a scale exposed to normal atmosphere (due to displacing less air).
If you took an object initially with the mass of a baseball, and heated it up to the Planck temperature, its total mass would be somewhere in the vicinity of a decent-sized moon. The Planck scale is serious business.