Brass doorknobs automatically disinfect themselves in about 8 hours.
18
Iron weighs more after it rusts.
68
Scientists are now able to grow 'beating' heart tissue in a lab!
162
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
The weight of a carat (200 milligrams), standard unit of measurement for gemstones, is based on the weight of the carob seed.
51
According to studies, men change their minds two to three times more often than women.
72