gen-define-the-water-cycle-and-give-one-short-worked-example-a902

Define the water cycle and give one short worked example.

# The Water Cycle The **water cycle** (also called the hydrological cycle) is the continuous movement of water on, above, and below Earth's surface. Water changes between three states—liquid, solid (ice), and gas (water vapor)—as it cycles through the environment. ## Key Processes: - **Evaporation**: Water changes from liquid to vapor (from oceans, lakes, rivers) - **Transpiration**: Water vapor released by plants - **Condensation**: Water vapor cools and forms clouds - **Precipitation**: Water falls as rain, snow, sleet, or hail - **Collection/Runoff**: Water gathers in bodies of water or soaks into ground --- ## Worked Example **Question**: If a small lake has a surface area of 2 km² and the evaporation rate is 5 mm per day, how much water evaporates in one day? **Solution**: - Surface area = 2 km² = 2,000,000 m² - Evaporation rate = 5 mm/day = 0.005 m/day Volume evaporated = Area × Depth Volume = 2,000,000 m² × 0.005 m = **10,000 m³** (or 10 million liters) This evaporated water enters the atmosphere, will eventually condense into clouds, and return as precipitation—completing the cycle.