That's almost true! It's not quite the average speed of particles that determines temperature, but rather the average kinetic energy of the particles.

Here's why:

* Kinetic energy is the energy of motion. The faster a particle moves, the more kinetic energy it has.

* Temperature is a measure of the average kinetic energy of the particles within a system.

So, while speed is a component of kinetic energy, it's not the only factor. For example, two particles with the same speed but different masses will have different kinetic energies. The heavier particle will have more kinetic energy.

Therefore, the temperature of an object is directly related to the average kinetic energy of its particles, which is influenced by both speed and mass.