The Royal Institution Annual Christmas Lectures to Young People

This third lecture of the series starts off as a piece of cake and ends with super-technology, as a laser pulse times a chemical reaction to the nearest millionth of a milldonth of a second. The connection is the intricate chemistry of plants: the starting point for nature's way of turning solar energy into useful work - the food chain.

Sir George Porter looks below the surface of the leaf to shew his young audience the molecular dance that turns sunlight into food.