17th January 2010

Last updated: 15 January 2010

This week - how and when the rock salt we use on our roads in winter was formed. We hear about the importance of pi. There's news of research into the history of coral reefs, plus a round up of new technology from CES in Las Vegas.

Rock salt history

Adam Walton discusses the geology of rock salt which we spread on our roads during winter. Supplies of rock salt have mede the headlines recently during the so called "big freeze" which saw ice and snow blanketing much of the UK. Heather Jackson, a geology interpretor from the National Museum of Wales discusses how rock salt was formed over 200 million years ago, and why it is such a good solution for icy roads.

Record breaking pi

A new record has recently been claimed for pi. French software engineer Fabrice Bellard has published his results, calculating pi to to 2.7 trillion digits. Professor Anatoly Zhigljavsky from Cardiff School of Mathematics joins the programme to discuss the importance and history of this intriguing mathematical constant.

3D is the new HD

Alan Daulby chats to BBC Technology reporter Maggie Shiels, who recently visited CES, the annual trade show in Las Vegas, which showcases new technology. 3DTV was on show in force, as were e-readers (electronic books) and tablet PCs.

Reefs rife with new life

Recent research by a team of scientists in Germany has studied the fossil records of coral reefs going back over 500 million years. We hear from Professor Wolfgang Kiessling who discusses the work showing that coral reefs have always been "hotspots" for the evolution of new species.

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