This week series host Kate Humble takes the Rough Scientists away from their epic quest for New Zealand gold, and sets them one of the show's toughest challenges yet. The team must measure the speed and melt of the Franz Josef Glacier, an awesome seven miles of ice.

In addition, the scientists have to keep themselves warm on the ice without lighting any fires, which involves building an ice lens and generating chemical heat.

With just a basic toolkit and the island's natural resources at their disposal, the team must draw on their pooled ingenuity and scientific knowledge to complete the tasks.

Explore the science

The scientists try to measure the speed and melt of the glacier, create an ice lens and design self-heating hand warmers.

Is the Franz Josef Glacier advancing or retreating? Jonathan Hare explains how the scientists reached their conclusions.

Is it possible to produce a lens out of ice? Discover the science behind this challenge and the problems the scientists encountered.

Mike Bullivant explores the chemical reactions involved in creating hand warmers.

Diaries

How did the Rough Scientists cope with living in the harsh environment on the edge of a glacier? Check out their personal diaries, which reveal whether Mike Bullivant succeeded in keeping the scientists' hands warm — and whether they all made it safely off the glacier.