Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
At room temperature, the average air molecule travels at the speed of a rifle bullet.
55
The bark of an older redwood tree is fireproof.
65
Forensic scientists can determine a person's sex, age, and race by examining a single strand of hair.
101
Oak trees produce 2,200 acorns in a season, but each acorn only has a 1 in 10,000 chance of becoming an oak tree.
304
A cubic yard of air weighs about 2 pounds at sea level.
31
It takes a photon 170,000 years to travel from the core of the Sun to the surface, but only 8 minutes to travel the rest of the way to Earth.
6
One barrel of petroleum holds 42 gallons.
20