* Kinetic Energy: Heat is a form of energy, and when you add heat to a gas, you're increasing the kinetic energy of its molecules. Kinetic energy is the energy of motion.

* Faster Motion: As the molecules gain kinetic energy, they move faster. This increased motion manifests as higher average speed.

* Increased Collisions: The faster-moving molecules collide more frequently and with greater force against each other and the walls of their container. This increased collision rate is what we perceive as higher pressure.

Key Points:

* Average Speed: We talk about the *average* speed of gas molecules because they are constantly moving in random directions.

* Temperature and Speed: The temperature of a gas is directly proportional to the average kinetic energy of its molecules. This means that higher temperatures correspond to higher average speeds.

* Distribution of Speeds: While the average speed increases, the molecules don't all move at the same speed. There's a distribution of speeds, with some molecules moving very slowly and others very quickly.

In summary, heating a gas increases the speed of its molecules due to the increase in kinetic energy, resulting in higher pressure and a broader distribution of molecular speeds.