When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
Pumice is the only rock that floats on water.
14
Brass doorknobs automatically disinfect themselves in about 8 hours.
18
A cesium atom in an atomic clock beats over nine billion times a second.
43
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
Your brain is 80% water.
525
In 1999, Harvard physicist Lene Hau was able to slow down light to 17 meters per second and in 2001, was able to stop light completely.
39
Indoor pollution is 10 times more toxic than outdoor pollution.
62