Yes, atoms and molecules are always in motion. This motion is called thermal motion and it is caused by the energy that the particles have. The more energy the particles have, the faster they will move. Thermal motion is responsible for many of the properties of matter, such as its temperature, pressure, and density.

At absolute zero, which is -273.15 degrees Celsius, atoms and molecules have the least amount of energy possible and they stop moving. However, this is only theoretical and cannot be achieved in practice. Even at very low temperatures, atoms and molecules still have some thermal motion.

The amount of thermal motion in a substance depends on its temperature. The higher the temperature, the more thermal motion there will be. This is because the particles have more energy at higher temperatures.

Thermal motion is also affected by the mass of the particles. The heavier the particles, the slower they will move. This is because the particles have more inertia at higher masses.

The type of material also affects thermal motion. Solids have the least thermal motion, followed by liquids, and then gases. This is because the particles are more closely packed together in solids and liquids, so they have less room to move. In gases, the particles are far apart, so they have more room to move.