Iron weighs more after it rusts.
16
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
The smell of freshly cut grass is actually a plant distress call.
31
In Arizona, a solar wind energy tower has been proposed that would generate as much energy as the Hoover Dam.
5
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
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
German chemists made a replica of a trophy the size of one molecule.
68