21 Science Facts You Won't Believe Are True

14. Colour Blindness Was Discovered When A Man Accidentally Bought His Mother Some Bright Red Stockings

Back in the late 1700s, English chemist John Dalton shocked everyone when he gifted his mother with a saucy pair of bright red stockings. Dalton, and the rest of his community, were Protestant Quakers, and would only wear plain clothes in dark colours to maintain modesty.

John Dalton was convinced that the stockings were blue, as was his brother, which indicated the the condition is genetic (which it is), and more common in men (which is also true, due to the fact that they only have one X chromosome). Dalton, however, thought that the effect was caused by the fluid in his eye being tinted blue (which it wasn't).

13. Life On Earth Used To Be Purple

These days, plants use chlorophyll to absorb the sun's rays and convert it into energy, and this gives them their green colour, but some scientists think that earlier life on the planet might have had a purple hue thanks to a molecule called retinal, which absorbs green light and reflects the blue and red wavelengths, making it appear purple.

Green, chlorophyll-using organisms are thought to have emerged because it worked in the exact opposite way, absorbing the blue and red wavelengths, and reflecting the green. This might explain why, even though most of the light that comes from the light is green, plants on Earth don't bother to absorb it.