Melvyn Bragg and guests discuss plasma, the fourth state of matter after solid, liquid and gas. As over ninety-nine percent of all observable matter in the Universe is plasma, planets like ours, with so little plasma and so much solid, liquid and gas, appear all the more remarkable. On the grand scale, plasma is what the Sun is made from and, when we look into the night sky, almost everything we can see with the naked eye is made of plasma. On the smallest scale, here on Earth, scientists make plasma to etch the microchips on which we rely for so much. Plasma is in the fluorescent light bulbs above our heads and, in laboratories around the world, it is the subject of tests to create, one day, an inexhaustible and clean source of energy from nuclear fusion.With Justin Wark Professor of Physics and Fellow of Trinity College at the University of OxfordKate Lancaster Research Fellow for Innovation and Impact at the York Plasma Institute at the University of Yorkand Bill Graham Professor of Physics at Queens University, BelfastProducer: Simon Tillotson.

Fusion milestone - the science behind the headlines. Laser fusion expert Kate Lancaster walks us through the technology that produced energy gain at the US's National Ignition Facility NIFWhirlwinds on Mars What the sounds of a dust devil passing over NASA's Mars Perseverance Rover tells us about the Martian atmosphere75 years of the transistor electronics revolution - where next for Moore's Law? December 16th 1947 was the day the first ever transistor device passed an electrical current. Trillions are made every day these days, powering our interconnected world. Roland recalls meeting some of the pioneers for the 50th anniversary, including Gordon Moore, and hears from Berkeley Dean of engineering Tsu-Jae King Liu how the revolution will continue for another 25 years.CrowdScience listener David was sanding down a door frame when he began wondering: Why it was that a rough thing like sandpaper is used to make another thing smoother? And furthermore, why does the process produce so much heat?We try to reduce friction in some cases by using lubricants, whilst at other times like braking at a traffic junction we depend upon friction entirely. Anand Jagatia heads to Edinburgh in Scotland, UK, to meet some true masters of this mysterious force: Curling players. What exactly is friction, and does thinking about it tell us something deeper about the universe?