- #1
iMatt
- 10
- 1
This came up whilst helping my kid with her GCSE physics so ought to be pretty straightforward. Here goes:
At his level the kinetic theory of matter is taught in a simple way and one "key point" which is stated time and time again is "the particles in a gas have more energy than the particles in a liquid which have more energy than the particles in a solid". Whist it is easy to see how this must be the case for the three states of the same substance it is not clear to me how it necessarily holds true when comparing different substances. For instance at room temperature one substance might be a solid and another might be liquid - does this "rule" always hold here? Or I might start with two equal masses of different solids at the same temperature then apply the same heat energy to both until one with lower melting point becomes liquid. Do the liquid particles have more energy than the particles of the substance that remains solid? If so this difference in energy must presumably have existed when both were still solid.
I don't know if the answer is tied in with considerations of different heat capacities for instance - I don't even know if the heat capacity and melting point of a substance are directly linked - but if I start listing all the things I don't know which might be relevant this email would get very long!
Hope someone can shed some light.
Thanks,
Matt
At his level the kinetic theory of matter is taught in a simple way and one "key point" which is stated time and time again is "the particles in a gas have more energy than the particles in a liquid which have more energy than the particles in a solid". Whist it is easy to see how this must be the case for the three states of the same substance it is not clear to me how it necessarily holds true when comparing different substances. For instance at room temperature one substance might be a solid and another might be liquid - does this "rule" always hold here? Or I might start with two equal masses of different solids at the same temperature then apply the same heat energy to both until one with lower melting point becomes liquid. Do the liquid particles have more energy than the particles of the substance that remains solid? If so this difference in energy must presumably have existed when both were still solid.
I don't know if the answer is tied in with considerations of different heat capacities for instance - I don't even know if the heat capacity and melting point of a substance are directly linked - but if I start listing all the things I don't know which might be relevant this email would get very long!
Hope someone can shed some light.
Thanks,
Matt