What makes rivers flow?

A river is always on the move, day and night, never stopping for a rest. It rushes over rocks and curls around bends. But what gives a river its get-up-and-go? The secret is a force you cannot see, pulling the water along.

Water always goes downhill

The big secret is gravity — the same pull that brings a ball back down when you throw it up. Gravity pulls everything towards the ground, and that includes water.

So water can never flow uphill on its own. It always rolls downhill, towards lower and lower places. A river is simply water following gravity all the way down.

From the hills to the sea

Most rivers begin high up in the hills and mountains. Rain falls there, and snow melts in the warm sun. All that water trickles together into tiny streams.

The little streams join up to make bigger streams, and those join to make a wide river. Helped by gravity, the river flows down and down, across the land, until at last it reaches the sea. That is the river’s long journey home.

Round and round again

The water does not stop at the sea. The sun warms it, and it rises into the sky as invisible vapour. It makes clouds, falls again as rain, and the whole trip starts over. This never-ending loop is called the water cycle.

Wonder fact: The longest rivers in the world are so long that the water takes weeks to travel from the mountains all the way to the sea!