Why do Rivers Curve?

We've all seen rivers lazily wind back and forth across a landscape - but, surprisingly, there’s nothing random about their path. MinuteEarth explains the formula that determines when a river bends, and when it goes straight.(by SCIENCEALERT staff)

river is drying up, the fast-moving water on the other side sweeps around the newly-formed curve with enough momentum to rush across the channel and SLAM into the bank on the other side, causing another curve to form, and then another, and another... until eventually you have a windy, snake-like river.

And fascinatingly, all over the world rivers generally follow the same pattern - the length of one S-shaped curve tends to be around six times the width of the channel. This means that rivers are pretty much fractals, because tiny, bendy streams are just smaller versions of their bigger relatives.

As long as nothing gets in the way of these curves, a river will become bendier and bendier until eventually the curves bump into themselves. When that happens, the river's channel follows the straighter path downhill, leaving behind detached oxbow lakes, which can be seen anywhere liquid used to flow - including on Mars.

Watch the episode to find out more about how a river's course changes over time, and the processes that have influenced the formation of the landscapes we see both here on Earth and in the rest of the Solar System.

Source: MinuteEarth