Water — three states and the water cycle

Water exists as:

• Solid (ice) — below 0°C
• Liquid (water) — between 0 and 100°C
• Gas (vapour/steam) — above 100°C (or slow evaporation at any temp)

The water cycle keeps water moving endlessly:

1. Evaporation — Sun heats ocean/lake water → becomes vapour.
2. Condensation — vapour cools at high altitude → forms clouds (tiny droplets).
3. Precipitation — droplets merge → fall as rain/snow.
4. Collection — water flows via rivers back to oceans. Cycle repeats.