Balsa wood is classified as a hard wood!
41
For every gallon of sea water, you get more than a quarter pound of salt.
45
One barrel of petroleum holds 42 gallons.
20
If the chemical sodium is dropped into water it will immediately and violently explode.
67
Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5
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
A cesium atom in an atomic clock beats over nine billion times a second.
43