Ocean waves are not moving walls of water. Instead, it's some kind of energy that moves along. But then, what happens to the water itself? This isn't just an idle question to ponder while watching the ocean — its answer may help protect us from it too. And it requires some sophisticated maths.
A massive earthquake hit Japan earlier today, registering 8.9 on the Richter scale and the largest ever recorded for Japan. The tsunami triggered by the quake brought a 10m high wall of water in northern Japan, and other countries are now waiting for it to hit their shores.
But what causes earthquakes and tsunamis and what can we do to protect ourselves from their destructive power?
Not so long ago, if you had a medical complaint, doctors had to open you up to see what it was. These days they have a range of sophisticated imaging techniques at their disposal, saving you the risk and pain of an operation. Chris Budd and Cathryn Mitchell look at the maths that isn't only responsible for these medical techniques, but also for much of the digital revolution.
Frances Elwell looks at the eddies and currents, from the pungent problem of sewage outflow to the search for bodies of people who have fallen into rivers, explaining that fluid mechanics lies behind it all.