Question: What do you mean by you study chaos?

Josh Dorrington answered on 7 May 2020:

Hi Sienna, thanks for the question!

What is chaos in science? It’s all about studying messy, real world problems, where tiny, unnoticeable changes can produce huge differences, making it very hard to work out what’s going to happen!
Normally in science, we can study some behaviour we’re interested in, like a ball dropping off a tower, a metal heating up, or a pendulum swinging back and forth, and by repeating experiments over and over again we can work out the rules that tell us how it behaves, and use that to make predictions.
But often in the real world it doesn’t all work that nicely. Why? Because simple things interacting with each other can behave in very complicated ways. A good example is what we call a double pendulum; you take one pendulum and attach it to the end of another one. Doesn’t sound too complicated but watch how it moves:

Even though we understand all the forces that control how the pendulum moves (friction, tension, gravity etc.) we can’t predict the double pendulum’s motion for very long at all, because tiny changes in the starting position completely change how it behaves.
These interactions can produce beautiful patterns like in that video, all emerging from very simple pieces. It’s one of the things I love about chaos!

The weather is chaotic too: all the rain and winds interact with eachother in such a complicated way that we can’t easily predict what the weather will do far into the future, even though we know quite well the laws that control it. We have to use huge supercomputers and delicate measurements to make sure we keep our errors as small as possible, which gives us as much time as possible before the errors grow so large we can’t make a useful weather forecast.
Sometimes the weather is more predictable than at other times, and I use computer models to try and understand why that is!