The smell of freshly cut grass is actually a plant distress call.
31
Sound travels fifteen times faster through steel than through air.
134
Sound travels about 4 times faster in water than in air.
408
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
The only letter not appearing on the Periodic Table is the letter "J".
180
Pumice is the only rock that floats on water.
14
The bark of an older redwood tree is fireproof.
65