Floating Clouds and Shining Stars

Dave Ansell

Why do clouds float in the sky? If Stars are so bright why is our sky dark at night? Does a ducks quack echo? We tackle these questions this week on Ask the Naked Scientists, as well as find out why the sky is blue, discover if there really could be UFO's out there, investigate why we produce tears in our eyes and explore why we can't start the morning without a yawn!