The Rough Scientists step up their search for gold. The deadline is looming for series host Kate Humble and the five Rough Scientists, who must find and extract enough gold to make a souvenir of their stay on New Zealand's south island. As the tension mounts, Kate sets three tough challenges: to extract gold from rock and sand, to build an altimeter, and to use the altimeter to find buried gold from a treasure map.

Kathy heads to the beach in her hunt for gold and Mike Bullivant and Mike Leahy extract gold from rock. Jonathan and Ellen create a portable altimeter to take with them on their expedition to search for gold.

Explore the Science

Find out how Jonathan and Ellen built their device to measure altitude to aid them in their hunt for hidden treasure. Jonathan explains the physics behind the challenge.

Discover how the Mikes used mercury sulfide to extract the gold. Mike Leahy explores the chemistry involved in getting gold from rock.

Diaries

Did the Rough Scientists feel under pressure to increase their pot of gold? Check out their personal diaries to find out.