💧 THE WATER CYCLE
PAGE 1 OF 5, ONE PLANET, ONE WATER SUPPLY
CLOSED LOOP
NOT NEW WATER — RECYCLED WATER
Earth is a closed system for water (at least on human timescales): almost every drop you drink has been ocean, cloud, ice, or inside a living thing before. The hydrologic (water) cycle moves H₂O between reservoirs — ocean, air, land ice, soil, plants, and groundwater. The same molecules change phase and location: liquid → invisible vapour → droplets or crystals → back to the surface. Nothing is created from scratch; it is rearranged by Sun and gravity.
🦕 FUN PERSPECTIVE
A sip of water might have been inside a fern, a T. rex, or a storm cloud 200 million years ago — same atoms, new ride.
RECYCLE!
MASS BALANCE
Total water on Earth stays roughly the same; only the form and place change
SALT VS FRESH
~97% ocean · ~2% ice · <1% liquid fresh where we live