Everything in an animal’s body is made out of cells. And these cells need chemicals, such as salt, in and around them to work properly. The chemical balance needs to be just right.
Alyse & Remi/flickr
Some animals, such as ghost shrimps can even cope with water that is saltier than normal seawater. It’s all down to evolution.
Two-footed walking, large human brains and using stone tools are all examples of evolution.
SpicyTruffel/Shutterstock
Understanding our evolution can tell us a lot about the health challenges we face today.
Nina Maile Gordon/The Conversation
Waves occur in all sorts of places, and it’s possible that waves you might see breaking at the beach are at the end of a very long journey.
Earth is really ancient, and humans have only been around for a tiny part of that time.
NASA
All the buildings and the cars and the restaurants, and the phones and even everything that’s inside of you… it all started with an exploding star, billions of years ago.
Baby teeth are only temporary. But they are important – so please look after them.
Philippe Put/flickr
Your teeth started to grow even before you were born.
Take a deep breath.
Flickr/Shenghung Lin
A sigh is the brain’s way of stopping the tiny sacks in your lung from collapsing.
This sounds like a good idea at first, but it’s not very practical.
Image Credit: NASA/Mark Vande Hei
Even fridge magnets have magnetic fields approximately 200 times stronger than Earth’s.
The world’s current tallest skyscraper is the Burj Khalifa in Dubai. It’s 828 metres tall. But we could go taller.
Flickr/Cristian Viarisio
It would be difficult, but we could probably build a tower over 2,000 metres tall, which would be like ten normal skyscrapers on top of each other! This is probably not a very good idea though.
The more fuel there is for the fire to burn, the bigger the fire. Leaves, trees and grass fuel the fire.
Flickr/bertknot
Bushfires require three key ingredients to ignite: heat, fuel and oxygen.
The Milky Way stretches across the sky near the Hungarian border village of Tachty in Slovakia.
EPA/PETER KOMKA
The diameter of the Milky Way is a billion billion kilometres.
Scientists built a small database showing which animals do and don’t fart. Not every animal in the world is on there, but it does have moon snails listed as a no.
Flickr/Florida Fish and Wildlife
One thing I can tell you is that a snail’s bottom is right over its head.
Flying high.
Shutterstock.
It’s hard to believe, but big storms and hurricanes are caused by tiny particles moving around in the atmosphere.
The short answer is that leaves fall off trees when they aren’t doing their job any more.
Emily Nunell/The Conversation CC-NY-BD
Leaves fall off trees when they aren’t doing their job any more. If there isn’t enough water, the leaf can be damaged and stop working.
It’s true they do have an amazing ability to be able to sleep standing up. But they do also sleep lying down. If you’re a horse, you need to be able to do both.
Flickr/Loco Steve
Horses can stand on three legs and rest the other leg. They can change the leg they rest so that all of their legs get a chance to have a break.
Pounds and shelters are not happy places for dogs to stay in for a long time, though. So everyone tries to find an unwanted dog a new home as quickly as possible.
Flickr/Rob Swatski
Different councils and different rescue organisations can have different rules about how long they can keep animals.
A brain freeze is an intense ‘squeezing’ sensation on your head.
Nina Maile Gordon/The Conversation
There are several different science ideas around why, but the answer may have something to do with what happens when we cool down the roof of our mouth.
Web of flies.
Shutterstock.
Spiders use different types of silk for different purposes – and not all of them are as strong as steel.
The experience that babies get from eavesdropping on their mother’s conversations in utero helps their brain tune into the language that they will learn to speak once they are born.
Emily Nunnell/The Conversation CC-BY-ND
Using a sing song voice helps babies tell the difference between words like ‘mummy’ or ‘daddy’.
Here’s a close-up picture of a head louse. The eggs of the female head louse are what we call ‘nits’.
We like to think that all creatures play a role in the local ecosystem. We’re especially interested in insects that provide a benefit for people too. But that’s not always how it is.
I spy with my little eye…
Shutterstock.
Pets, like guinea pigs, lead very different lives to humans – and that’s why they need very different eyes, too.