The scientists turned gold prospectors continue their epic search for gold in the wilds of New Zealand's South Island.

Presenter Kate Humble struggles with the team as they battle to extract enough gold to make a souvenir by the end of the series. To add to the half a gram they extracted in the first week, they adopt increasingly bizarre methods to get rich and solve science puzzles.

Explore the science

Amid the humour and fun, the Rough Scientists construct a spectacular giant panning machine to use in the river, do strange things with sheep's wool to make their own cosmetics, and find out what trees can reveal about earthquakes.

If you were wondering how the automated panning system was constructed, explore the panning challenge in more depth. Discover which stages of panning can be automated and how the scientists used simple technology to pump water up to the sluice.

What is lanolin and how can it be used in making hand cream? Chemist Mike Bullivant explains how he concocted his cream and made it smell a little more pleasant.

Diaries

How did the scientists cope with this week's challenges?
Were Mike L, Jonathan and Kathy impressed with their giant panning machine? Did Ellen think she would be able to predict the age of the trees? Did Mike B enjoy making his hand cream? Read each of the Rough Scientists' personal diaries to find out what life was really like in New Zealand.

Forum

Could you come up with a different design for an automated panning device? Send your ideas to the Open2 Forum. Mike Leahy and Jonathan Hare will be on hand over the next few weeks to answer your questions about the challenges. Why not make some suggestions if you think there are other ways of approaching the problems the Rough Scientists have faced so far.