Here's why:

* Atoms in a solid are held together by strong bonds. These bonds restrict the atoms' movements, preventing them from freely moving around like particles in a liquid or gas.

* Even at absolute zero (0 Kelvin), atoms still vibrate. This is due to the inherent quantum nature of matter, where there's always a minimum energy level present, even at the lowest temperature.

* As temperature increases, the amplitude of these vibrations increases. This means the atoms move further from their fixed positions.

* At a certain temperature, the vibrations can become so strong that the bonds holding the solid together break. This is what causes melting.

In summary:

* Yes, particles in a solid vibrate around a fixed point.

* The amplitude of these vibrations depends on the temperature.

* These vibrations are a fundamental property of matter and don't stop even at absolute zero.

Let me know if you have any more questions!