This week, we answer Paul's question about the size of a diamond you could make with the carbon in a piece of coal, we discuss where butterflies in your stomach come from, discuss the basis of gut instinct, and ask how much magnesium you need and how the body absorbs it. Join 567 CapeTalk's Kieno Kammies and Dr Chris Smith to find out... Like this podcast? Please help us by supporting the Naked Scientists