Airports that are at higher altitudes require a longer airstrip due to lower air density.
39
The brain case [of Neanderthals] on the average was more than 13 percent larger than that of the average of modern man
61
Balsa wood is classified as a hard wood!
41
Pumice is the only rock that floats on water.
14
One cubic foot of gold weighs more than 1,200 pounds!
78
A cesium atom in an atomic clock beats over nine billion times a second.
43
During photosynthesis, plants emit light humans can’t see, but NASA can see that light from space - and they've even made maps of it!
21