Brass doorknobs automatically disinfect themselves in about 8 hours.
18
Pumice is the only rock that floats on water.
14
Scientists aren't sure what color dinosaurs were.
312
The weight of a carat (200 milligrams), standard unit of measurement for gemstones, is based on the weight of the carob seed.
51
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
Marie Curie, the Nobel prize winning scientist who discovered radium, died of radiation poisoning.
57