Final answer:
Particles in a solid state are tightly packed together, vibrating without changing position due to strong intermolecular forces.
Step-by-step explanation:
In the solid state, particles (atoms or molecules) stay tightly packed together and vibrate without changing position. They are in fixed positions relative to one another due to their lack of energy to move and the strong intermolecular forces keeping them together. This is in contrast to the other states of matter: in a liquid, particles are also closely packed but are able to slide over each other and assume the shape of their container; in a gas, particles are far apart and move freely in space; and in a plasma, particles are ionized and move independently as well.