Final answer:
When a solid turns into a liquid, the thermal energy increases because energy is required to break the bonds between particles. The amount of water stays the same in the water cycle as the water undergoes different processes but remains constant on Earth.
Step-by-step explanation:
When a solid turns into a liquid, the thermal energy increases. Energy is required to melt a solid because the bonds between the particles in the solid must be broken. The energy involved in a phase change is used to break these bonds, resulting in no increase in the kinetic energies of the particles and no rise in temperature. The same principle applies when a liquid turns into a gas. Energy is needed to overcome the attractive forces between particles in the liquid.
In the water cycle, the amount of water stays the same. Water undergoes processes like evaporation from bodies of water, condensation in the atmosphere, and precipitation, but the total amount of water on Earth remains constant. This is because water is continuously cycling between the Earth's surface and the atmosphere.