Kissing actually has the biological purpose of passing on biological information and chemical signals to assess mating possibilities and status.
9
Only 12,000 years ago there was a species closely related to modern humans called Homo floresiensis that had been living on an Indonesian Island. They used fire and rather advanced tools, yet were only about 3 feet tall and weighed around 25kg.
15
The average temperature at 40,000 feet above sea level is -60 F.
56
The force of a suction cup is calculated using F=AP.
15
Iron weighs more after it rusts.
68
Hot water can freeze faster than cold water.
181
A cesium atom in an atomic clock beats over nine billion times a second.
43