Birds spend a lot of time and energy singing, but they don't do it the same way in every season of the year. And some can't sing at all. What's the purpose of birdsong?
The short answer is yes, but it’s really, really difficult.
People have probably always wanted clean and healthy teeth. What they historically used to achieve dental hygiene might surprise you.
The very hottest stars actually glow blue.
Electricity happens when electrons move from one atom to another.
We need to understand what a swallow's nest is really for – and it is not mainly for sleeping.
Having different coloured eyes is quite unusual, but it happens in many species throughout the animal kingdom.
Emperor penguins have a few hidden tricks to stay warm, like blood vessels in the nose arranged so they can regain most of the heat that would be lost by breathing.
Think of it like a ladder. You might not be at the top right now, but each new thing you learn takes you a step closer and means that your parents can relax the rules a little.
Human eyes are very complex and are good at doing many jobs at once, while spiders have different sorts of eyes that do different jobs.
It's true that here on Earth, if you want to burn something you need oxygen. But the Sun is different. It is not burning with the same kind of flame you would have on Earth if you burned a candle.
Being double jointed doesn't mean you have an extra joint – an expert in biomechanics explains what makes some people doubly bendy.
Writing has only been a part of the human story for the last 5,000 years. In comparison, humans began to communicate using speech some 50,000 years ago.
An expert explains all the wonderful ways the atmosphere protects life on Earth.
The short answer is that leeches need blood to grow and reproduce. But it's in their interests to do it carefully, without causing too much pain, and in spots that are hard to find.
Dinosaurs ruled the Earth for about 180 million years. But around 66 million years ago, a huge rock from outer space (called an asteroid) smashed into the Earth. Then things got worse for dinosaurs.
As strange as it sounds, rocks are made from stardust.
Ladybirds do not have tails because they have no backbones.
A scientist explains how global warming is affecting the entire world – from the mountains, to the sea.
We know very little about the deep sea and how its inhabitants, including anglerfish, will respond to change. In fact, more people have walked on the Moon than have been to the bottom of the ocean.