Solids, liquids and gases. In a solid like this brick, the particles are regularly arranged touching their neighbours and move only by vibrating. This explains why solids have a fixed shape.

The focus is that matter, whether solid, liquid, or gas, is made up of particles; that dissolving and evaporation happen at the particle level; and that models can help explain these processes that we ...

Although gas-solid systems are characterized by the same mechanical interactions that are present in granular flows (e.g., collisions between two particles), the physical nature of the gas-solid ...

Students explore the attractions and motion of atoms and molecules as they experiment with and observe the heating and cooling of a solid, liquid, and gas.