The water cycle is an essential part of the natural system. Plants and animals could not exist without this continual return of fresh water to the Earth’s surface.

Powered by the sun’s heat and light energy, the water cycle continuously keeps water moving from one form to another – ice to liquid water to water vapor – which allows it to continually replenish. To understand the water cycle, follow a drop of water along the cycle, using the diagram to help.

Let’s start in the ocean. Our water drop is floating on the surface of the sea, and it’s salty. The heat from the sun warms it and evaporates it into water vapor, leaving the salt behind.

The vapor rises into the air, where the wind grabs it and blows it over the land. When the vapor floats high enough to get cold, it changes back into a liquid through a process called condensation. If the air is cold enough, it will turn into a cloud along with small particles of dust, smoke and salt crystals (but not as much salt as in the ocean).

Eventually the little drop meets up with other drops because of its high surface tension and falls to the Earth as precipitation – like rain, snow and hail. If it falls on a leaf, it will probably evaporate and begin the process of heading for the clouds again. If it misses the leaf, the drop may become a land rover, staying on Earth’s surface. If the drop lands in an urban area, it might hit your home’s roof and travel down the gutter, onto your driveway, down the curb and into a storm drain, ending up in a small creek. The creek may flow into a larger river, and the drop then returns to the ocean once again. Quite a busy life for one little drop of water!