## acceleration

How large are the forces acting on a gymnast swinging on the high bar?

*Plus*spoke to

**Peter Wadhams**from the Polar Ocean Physics Group at the University of Cambridge to get a glimpse of the group's work.

**Mario Livio**explains how not only shapes, but also laws of nature can be symmetrical, and how this aids our understanding of the universe.

*Plus*, we heard how a simple mathematical equation became the subject of a debate in the UK parliament.

**Chris Budd**and

**Chris Sangwin**continue the story of the mighty quadratic equation.

**Herbert Huppert**tells us what happens when two fluids of different densities meet, for example when volcanos erupt and hot ash-laden air is poured out into the atmosphere.

**R. McNeill Alexander**finds some answers.