The first vending machine was created in the 1st century AD. It dispensed holy water.
You can tell the age of a horse from its teeth. This is what the phrase 'don't look a gift horse in the mouth' is referring to (basically, 'don't question the value of a gift').
Morphine was named after Morpheus, a Greek god of sleep and dreams.
Pigeons were the first domesticated bird.
Domesticated corn (as in the type we grow for food) cannot survive without human aid as it can't naturally reproduce.
Studying done while sleep-deprived is 40% less likely to be remembered.
The Guiness Book of World Records has stopped recoginzing attempts to break the sleep deprivation world record as they deem it too dangerous.
The platypus experiences more REM sleep than any other mammal (~14 hours a day).
The BIC biro was patented in 1938.
A medium-sized cumulus (Cumulus Mediocris) cloud can weigh as much as 80 elephants.
The optic nerves route optical data to the limbic system as well as the conscious mind, so some blind people can respond to facial expressions without seeing them. They can even catch yawns this way.
In the German tradition, the letter labelling of musical notes went up to 'h'. This meant that Bach could spell his name in notes, which he actually did, using B-A-C-H as a motif in some of his music.
The number zero used to be called 'cipher'.
The type O blood type was supposed to be called type zero, but it was misread when written down.
Water expands as it freezes because ice's crystal structure has more gaps between molecules than water does as a liquid.
Alcohol is one of the most powerful suppressors of REM sleep.
It is more dangerous to drive when sleep-deprived than when tipsy (MythBusters also did a segment on this; I couldn't find a good clip but it's Episode 152 - Arrow Machine Gun)
Our sensitivity to blue light goes all the way back to our ocean ancestors. These animals' eyesight developed in blue light as the water filters shorter wavelengths of light like red and yellow, and blue is left over.
Snakes have two penises, and just like how we can have a dominant hand, they can have a dominant penis.
The symbol for the letter 'A' is an upside-down ox's head. It can be traced back to the first letter of the Phoenician alphabet, aleph.
We don't know whether the first language was spoken or signed
Caffeine doesn't give you 'more energy', it just blocks the adenosine receptors in your brain that make you feel tired.
Humans sleep less than other primates, but have significantly more REM sleep.
Austistic individuals have on average 30-50% less REM sleep than a neurotypical sleeping the same amount of time.
After 10 days of getting only 6 hours sleep a night, you are as impaired as you would be if you stayed up for 24 hours.
The sleep-deprived brain cannot tell how sleep-deprived it is. Sleep-deprived people almost always underestimate how much of an impact their lack of sleep has on them.
Humans are the only mammals that willingly delay sleep.