Here's why:
* Temperature: A measure of the average kinetic energy of the particles in a substance. Kinetic energy is the energy of motion, so faster-moving particles mean higher temperature.
* Particle Speed: The higher the temperature, the faster the particles are moving on average.
* Energy: Temperature is directly related to the internal energy of a substance. This internal energy includes the kinetic energy of the particles and the potential energy due to the forces between them.
In summary: Temperature is a measure of the average kinetic energy of particles, which directly relates to their speed and the overall energy of the substance.