Tiny moving particles

You can build a model of particles from dry beans or buttons in a shallow tray. For a solid, pack the beans close together in neat rows and give the tray a very small shake. For a liquid, keep them close but not in rows, and shake a bit more so that they slide past each other. For a gas, use only a few beans in the same tray and shake it hard, so that they spread out and bounce. Shaking is like adding thermal energy. A chef’s kitchen uses this idea. A pat of butter in a warm pan melts because heat makes its particles move more until they slide. Rice cooks in a pot with a lid, and steam rises. The explanation uses a claim, evidence and reasoning: heat makes particles move more, so a solid can melt.