At what temperature does sea water freeze? Why do aeroplanes not freeze when up in the cold air? Why can't we use sand on icy roads? We tackle these chilling questions on this week's show as well as reveal if parachutes could slow down a space ship, whether we can see stars from the moon, if smoke stacks can be harvested for energy and if wood vapourises before it burns! Like this podcast? Please help us by supporting the Naked Scientists