When thermal conduction is occurring within a solid, what happens to its
particles?

Both fast particles and slow particles speed up

Explanation:

Their atoms, or molecules that make them up, are closer together, so they can transfer energy between them much more efficiently. The particles of a solid are packed together tightly in an ordered fashion. There is little movement. The particles of a liquid have a little more freedom, being able to glide over and past each other, but are still relatively close together, so passing energy is easily accomplished. The particles of a gas are spaced far apart. For them to transfer energy, they have to bump into each other.

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