Why do we hum?
Chris Smith from The Naked Scientists takes on YOUR questions. Can contact lenses make your eyes better than perfect vision? How intense can deja-vu be? Why do we hum? Why are there more jetstreams in the Northern Hemisphere? Why doesn't armpit hair grow like head hair? Why are mushroom clouds mushroom-shaped? Can you be allergic to electricity? And why does gravity attract mass? Plus, they say in space, no one can hear you scream, but is that true...?