The diagram shows molecules in a fluid. Explain the sequence of events that happens when this fluid cools down. Be sure to focus on what happens to the molecules and to the fluid in general. Five events should be included in your answer.

Answer:

As the fluid cools down, the following sequence of events occurs: 1. The thermal energy of the fluid decreases. 2. The molecules lose kinetic energy and begin to move more slowly. 3. As the molecules slow down, the attractive forces between them pull them closer together. 4. Because the molecules are closer together, the fluid's volume decreases and its density increases (thermal contraction). 5. Eventually, the movement slows enough that the fluid may undergo a phase change, such as freezing into a solid.