Freezing

Bob the water droplet set off on his journey to explore the states of matter. The first place he came to was very cold, so he lost thermal energy and froze. He suddenly realized he had discovered a state of matter called the solid state and that he just went through a change called freezing. His molecules were packed tightly together with lots of force and only vibrated. He had a fixed shape and volume.

Melting

Bob finally made it out of the cold and into a desert. It was so hot that Bob stopped and decided to take a nap in a hammock. When he woke up he felt his particles moving moderately fast because he had gained thermal energy. Then he realized he had turned back into a liquid. In the liquid state his molecules had more space to move around and went moderately fast in straight lines until they hit each other. He had no fixed shape but he did have a fixed volume.

Vaporization

Bob loved the temperature so much he decided to stay for a few days. After a few hours he felt very energized because his molecules where moving super fast and spread out. He had turned into a gas! He had turned into a gas because he gained lots of thermal energy. His particles were very spread out and the fastest of the states of matter (not including plasma). He had no fixed shape or volume.

Condensation

Bob loved being a gas because his particles moved very fast and he felt good with his particles spread out. He spent the night as a gas. When he woke up he felt less energized because he had turned back into a liquid by losing thermal energy and going through a change called condensation where he went through the gas to liquid state. Then he realized he had collected on a blade of grass near other water droplets.