* Molecular Structure: The size of a molecule is determined by the atoms it's composed of and the bonds between them. Heating doesn't change the fundamental structure of a molecule.
* Kinetic Energy: When you heat a gas, you increase the average kinetic energy of the molecules. This means they move faster and collide with each other and the container walls more frequently.
* Increased Spacing: The increased movement causes the gas molecules to spread out further, taking up more space. This is why gases expand when heated.
Think of it like this: Imagine a room full of people. If everyone stands still, they take up a certain amount of space. If you tell everyone to start running around, they'll need more space to move freely. The people themselves haven't gotten bigger, but their increased movement requires more space.
In Summary:
* Heating a gas increases the kinetic energy of its molecules, making them move faster.
* This increased movement causes the molecules to spread out, resulting in an expansion of the gas.
* The individual molecules themselves do not physically grow larger.
