Brian Cox with Simon Pegg and Jim Al-Khalili
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Brian Cox demonstrates why atoms are empty

Brian Cox gives a science lesson to celebrities. The comedian Simon Pegg and physicist Jim Al-Khalili help him explain standing waves in a demonstration to show why atoms are so large and empty.

BBC Two's A Night With The Stars is broadcast on Sunday 18 December 2011 at 21:00 GMT. Or watch later on BBC iPlayer.