Here's why:

* Temperature is a measure of the average kinetic energy of the particles in a substance. Kinetic energy is the energy of motion.

* Faster particles have more kinetic energy. The faster the particles move, the more kinetic energy they possess.

* More kinetic energy means higher temperature. Since temperature reflects the average kinetic energy of particles, a higher average kinetic energy means a higher temperature.

Think of it like this:

Imagine a group of people standing still. This represents a low temperature. Now imagine them all running around quickly. This represents a higher temperature. The faster they move, the hotter it feels!