Your first instinct might have been to say oxygen, but in fact air only contains 20% oxygen, whereas nitrogen makes up 78% of the air we breathe, along with 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases.

The Kuhn gynaecological papyrus, written in around 1800BC, is one of the earliest descriptions of contraception. It describes using a clump of crocodile dung as a pessary before sex to prevent sperm entering the womb.

This surprisingly common phobia can also include dead chickens and eggs. It takes its name from the Greek alektor, meaning a rooster.

It's also OK to call them a pod, or even a school. But not a shoal.

The "10% percent of the brain" myth isn't true. It's been perpetuated for years, possibly because it's appealing to think that we could all be geniuses if we could tap into the other 90%. We actually use almost every part of the brain, and our entire brains are active most of the time.

Almost every geographical feature on Venus has a female name (usually a mythological goddess), except for three features, one of which is Maxwell Montes, the highest mountain on the planet, named after physicist James Clerk Maxwell.

Lady Liberty is made from copper. She was a traditional burnished red-orange at first, but the copper reacted with air and moisture and developed a pale green outer layer called a patina.

All season fluctuations are due to the fact that our planet is tilted on its axis. The Earth travels in a loop around the sun each year. Summer happens in the hemisphere tilted towards the sun, and winter happens in the hemisphere tilted away from the sun.

Astronauts returning from a spacewalk have reported smells of "seared steak" or"hot metal". According to chemist Steve Pearce, the smell is caused by high-energy vibrations in particles brought back inside which mix with the air.

It's the official medical term for the back of your hand.

The Atacama desert is the driest nonpolar location in the world, but the absolute driest location is the Dry Valleys, a 4,800-square-kilometre region in Antarctica that has seen no rain for nearly 2 million years. It's considered to be the place on Earth that's most like Mars.

Christopher Columbus was determined to find a direct water-based trading route west from Europe to Asia, but he never did. Instead, he accidentally stumbled upon the Americas, changing the course of world history forever.