Yawning is contagious. Even thinking about yawning is enough. In fact, there's a 50% that you're about to, or just did, yawn.

Yawning is a reflex of simultaneous inhalation of air and stretching the ear drums followed by an exhalation of breath. It is linked to tiredness, boredom, overwork, stress and lack of stimulation. In humans, yawning is often triggered by others yawning around you.

In this way, it is contagious. Interestingly enough, this contagiousness has also been observed in chimpanzees and dogs. So why is that when we see those around us yawning, we too want to yawn?

Some studies have suggested that infectious yawning developed to keep groups of animals alert. The increase of oxygen to their brain will help ready them for action. Other studies have suggested that yawning is associated with the cooling of the brain.

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Those stars and colours you see when you rub your eyes are called phosphenes.

Have you ever closed your eyes, rubbed them and seen stars? Or at least little pops of light? It turns out that those pops of light have a name: phosphenes.

They are a phenomenon characterized by seeing light without light actually entering the eye. This rubbing mechanically stimulates the cells of the retina causing this effect. Sometimes, these phosphenes can still be seen for moments after you open your eyes.

Meditators have also reported experiencing phosphenes, and they have actually been known since antiquity. Ancient Greeks described them. Other reasons people ‘see stars’ are because of sneezing, coughing, blowing your nose or receiving a blow to the head.

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The total weight of all the ants on Earth is about the same as the weight of all the humans on earth.

Unless you leave food out and attract them, humans rarely have a need to think about ants. They're tiny, not poisonous and not particularly terrifying, like say, spiders. However, they far outnumber humans on earth--by one million to one!

Funnily enough, they are also roughly a millionth of a human in size too. Do the math--the total weight of all the ants on earth matches the total weight of the entire human population.

There are 10,000 different types of ants and they've been around for a long time. Ancients ants have been discovered in fossilized sap from 100 million years ago!

Over time, ants have changed very little. Their way of life and survival is successful. Some scientists attribute this to their unselfish ways. Ants live in colonies and bring their prey back to their many relatives to share.

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Grapes EXPLODE when you put them in the microwave!

You may have heard of frozen grapes as a tasty snack, but what about heating grapes in the microwave? You probably shouldn't try this one. It turns out that grapes react very oddly when they're microwaved.

Since grapes are full of moisture, when they are microwaved, that moisture turns to steam. If the stem is still attached to the grape and there is nowhere for the steam to escape, it will explode slightly and rupture the skin.

If you place two grapes close together with their stem holes facing each other, some arcing and sparking will occur. If there is just a single grape with its stem hole open, it will let out a stream of steam. Good thing we don't serve grapes warm.

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A Rubik's cube has 43,252,003,274,489,856,000 possible configurations.

With 6 colored sides, 21 pieces and 54 outer surfaces, there's a combined total of over 43quintilliondifferent possible configurations. To put that into perspective: if you turned the Rubik's cube once every second it would take you1400 trillion yearsto finish to go through all the configurations.If you had started this project during the Big Bang, you still wouldn't be done yet.

Another way to think about this is, if a person had as many Rubik's cubes as there were possible configurations, they could cover the surface of the Earth 275 times. And if one considers the number of configurations you could reach by disassembling and reassembling the cube, the number would be nearly 12 times that many.(source)