QandA

Q&A Tabs

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

Lobsters and other shellfish have harmful bacteria naturally present in their flesh. Once the lobster is dead, these bacteria can rapidly multiply and release toxins that may not be destroyed by...

Mammals remove excess nitrogen from their bodies by converting it to a dilute solution of urea, stored in the bladder. Birds convert nitrogen to uric acid instead: this is metabolically more...

It depends on how high (or low) you set the bar of fluency. Ziad Fazah, born in Liberia, brought up in Beirut and now living in Brazil, claims to be the world's greatest living polyglot, with...

Astronomer Fred Hoyle was the first to point out that if you could drive a car upwards at 95km/h (60mph), it would only take about an hour to get into space. To get to the Moon would take a little...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...

Recent Q&A...

When an earthquake strikes, different vibrations travel through the ground at different speeds. The Primary (P-wave) vibrations travel about twice as fast as the Secondary (S-wave) vibrations that...

Vision defects such as myopia (short-sightedness) aren’t caused by just one single gene. There’s some evidence that short-sighted people have a higher than average IQ, which may be...

There is a long history to the idea that black holes may connect with other regions of the Universe, or other universes entirely, but this is purely speculation. Some physicists have attempted to...

No. In fact, a 2014 study at the University of California, Berkeley found that being very rich or very poor were both associated with higher levels of mental illness. This doesn’t...

Empathy builds on the ability to see things from another person’s point of view, which most children acquire at around four or five years. But being fully empathic also means being able to...

Our skin contains lots of nerve endings that respond to different stimuli. There are receptors for touch, vibration, heat, cold and pain – but not for wetness. Water is such a ubiquitous...

It’s all down to the method of delivery. Venoms must be injected to be effective, whereas poisons can come into contact with skin, or be inhaled, eaten or touched. So the puffer fish is...

Reading is a complex, multi-layered process, starting with detecting letters, recognising words and groups of words, then analysing sentence structure and meaning.

Different areas of the...

Men grow beards because the hair follicles on their jaw are stimulated by the hormone dihydrotestosterone (DHT), which is produced from testosterone. Women have the same number of follicle cells...

Studies using functional magnetic resonance imaging (fMRI) have shown that scratching causes patterns of brain activity that are associated with pleasure and reward. This effect is strongest when...

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