The birthday paradox

Take a group of 23 people. What is the probability that two of them share the same birthday? Or let’s take a different approach. How many people do you need to make sure that the probability that two of them share the same birthday is close to 100%? On first glance, 367 seems like a probable answer (as there as 366 days during a year including February 29th). But while you would need as many to get to exactly 100%, you need much less to reach 99% probability.

Why is yawning contagious?

There is no doubt that yawning is contagious. I mean, imagine someone with their mouth wide open, squinting eyes, taking a long breath in, then a short one out. Are you yawning yet? Almost anything that reminds us of yawning, like reading about it, seeing a video of it, will cause us to yawn. Just thinking about yawning can be enough. It’s actually quite hard to write about yawning because you start yawning all the time. During the research and writing of this post I yawned 34 times. I counted. Ok, make that 35 times.

What can marshmallows teach us about self-control?

The ability to delay gratification, being able to focus on the important things and plan for the future, rather than just taking the easy, immediate reward, has been linked to success in life. But do people have an innate sense of self-control? And how do we test it? As it turns out, with marshmallows.

How do organisms glow? And why?

Summer is just around the corner and soon fireflies will start buzzing and flashing all through the night. Fireflies are winged beetles that produce light in a range of colours (depending on the species). Glow worms, as seen in the above picture,  also produce light. They’re not actually worms but fly larvae and live in caves. But, in fact, there aren’t that many more terrestrial animals that emit light. Bioluminescence is much more common in the sea, although, strangely, no freshwater animals use it. But how is this light produced? And why?

How do humans breathe in space?

Humans can only live comfortably in a small variety of places. We can’t live underwater. Or higher than a certain altitude, where there is too little oxygen. We can only live in a very small slice of the atmosphere, from sea level up to 3-4000 m. If you think about it, the human habitable zone is really tiny, especially when compared to how big the universe is. Yet, we can fly on planes at much higher altitudes, survive underwater for months at a time in a submarine and at any moment there are one or more scientists aboard the International …

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South is North and North is South – Magnetic pole reversal

The world was supposed to end on December 21st, 2012. Or at least, some people thought so. One of the proposed hypotheses was that on that fateful December day the magnetic poles would switch, north would be south and south would be north, and this, somehow, was going to make things very very bad for us humans. Of course, this didn’t happen. Surprisingly, predictions based on the end of a calendar by an ancient civilization that didn’t even know what geology was turned out to be wrong. Strange. That said, geomagnetic reversal is a real phenomenon and poles do swap …

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Why you shouldn’t eat a polar bear

Polar bears are cute, especially if they’re still cubs. Knut, a polar bear born in captivity in a zoo in Berlin, was a media sensation. However, they are quite dangerous. Polar bears are big (adults can weigh up to 700 kg), fast (can sprint up to 40 km/h), aggressive, very protective of their young and can kill you with one lazy swipe of their furry paw. Polar explorers are very aware of the dangers of polar bear and bringing a rifle on an expedition is mandatory. So why should you not eat a polar bear? Well, actually, I’m exaggerating, you …

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Methane release in the Arctic could spell disaster?

There are billions of tons of methane gas in the arctic circle. The gas is trapped inside permafrost, the layer of land that remains frozen throughout the year, and inside clathrates, which are physical compounds of methane trapped inside an ice crystal structure. Clathrates are found at the bottom of the sea, the temperature and pressure there keep them stable. The picture above shows methane bubbles trapped in ice at Abraham Lake in Canada. There’s not much snowfall at this lake and that’s why we can see the bare icy surface. The release of methane is not unique to it …

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Are expensive cosmetics worth it?

For some reason, maybe because I’ve been researching this article for a while, google thinks that I want to buy anti-ageing creams. Wherever I surf, I see ads trying to sell me all sorts of wonder cosmetics designed to reduce my wrinkles. Retinol this, vitamin C that. I even found a cream that costs 700 dollars for 50 ml (or $14000 a litre!). But do these creams even work? Are they really worth the money? Are there any valid scientific studies on their effectiveness? (Spoiler: nope).

As ice melts, sea levels can fall

The ice sheets are melting. With global warming practically a certainty, melting ice sheets will cause average sea levels to increase. However, in some parts of the world sea levels will decrease. How?