During evaporation and condensation, water changes its state of matter between liquid and gas, a fundamental process in the water cycle.
Evaporation: Liquid to Gas
Evaporation is the process where liquid water transforms into water vapor, which is a gas. According to the reference material, "Water goes from a liquid state to a gas state."
- Process: Molecules in liquid water gain enough energy (usually from heat) to break free from the liquid's surface and enter the air as a gas.
- Example: Puddles drying up on a sunny day demonstrate evaporation. The sun's heat provides the energy needed for the water to change state.
Condensation: Gas to Liquid
Condensation is the reverse process of evaporation, where water vapor (gas) changes back into liquid water. The reference states that "Water goes from a gas state to a liquid state."
- Process: Water vapor molecules lose energy, slow down, and come closer together. When they lose enough energy, they form liquid water.
- Example: Dew forming on grass in the morning is condensation. The air cools overnight, causing water vapor in the air to condense on the cool grass blades.
Summary Table
| Process | Initial State | Final State | Energy Change |
|---|---|---|---|
| Evaporation | Liquid | Gas | Gains Energy |
| Condensation | Gas | Liquid | Loses Energy |
