Why does my watery windscreen turn to ice?

Mike got in touch to say: "When the outside temperature is hovering around the freezing mark, the condensation or dew on my automobile windshield is in a liquid state. But if I wipe the windshield, the liquid water changes to ice. Why is that?" To help, Adam Murphy spoke to Liz Thomas from the British Antarctic Survey... Like this podcast? Please help us by supporting the Naked Scientists