At 50 feet underwater, blood looks green, because there are no red wavelengths of light at this depth.
Amazing fact: water
One single drop of water contains about 5,000,000,000,000,000,000,000 (5 sextillion) atoms.Water expands by 9% when it freezes. Frozen water (ice) is lighter than water, which is why ice floats in water.
Amazing fact: sunlight
The amount of sunlight reaching the earth's surface is 6,000 times the amount of energy used by all human beings worldwide. The total amount of fossil fuel used by humans since the start of civilization is equivalent to less than 30 days of sunshine.
Amazing fact: human eye
The smallest particle, or dot, that can be seen by the unaided human eye, is about 0.004 inches in size.
Amazing fact: gases
Dry air contains 78% nitrogen, 20% oxygen, 0.9% argon, 0.4-1% water vapour, 0.03% carbon dioxide, and small amounts of other gases.
