Airports that are at higher altitudes require a longer airstrip due to lower air density.
39
Because heat expands the metal, the Eiffel Tower always leans away from the sun.
79
Brass doorknobs automatically disinfect themselves in about 8 hours.
18
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
0.3% of solar energy from the Sahara is enough to power the whole of Europe.
310
If the chemical sodium is dropped into water it will immediately and violently explode.
67
The smell of freshly cut grass is actually a plant distress call.
31
Nearly 50% of the world's scientists are assigned to military projects.
71