Because heat expands the metal, the Eiffel Tower always leans away from the sun.
79
One 75-watt bulb gives more light than three 25-watt bulbs.
57
Blue eyes are a genetic mutation. Before the mutation occured, all humans had brown eyes.
89
A cesium atom in an atomic clock beats over nine billion times a second.
43
A cubic yard of air weighs about 2 pounds at sea level.
31