Pluto is a rocky, icy ball-shaped object far, far away in Space – sometimes as many as 4.7 billion miles from Earth! It’s smaller than Earth’s Moon and so far away that we didn’t know it was there until 1930.
When I was a little girl, people thought Pluto was a planet, like Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune – the other planets in our Solar System. But when scientists studied Pluto to learn more about it, they realised it isn’t quite like the other planets.
So let’s find out more about Pluto and whether it is a real planet or not…
Storms are a kind of bad weather, usually made up of strong winds and rain or hail. They can cause lots of damage by blowing bits off buildings and trees, causing water to overflow from rivers and streams, or making huge sea-waves that crash onto the land.
Storms happen every year and are a normal part of the weather here on Earth. But some storms are stronger than others; the stronger the storm, the more damage it could cause. So, scientists have come up with a way to keep track of them – let’s find out how they do it…
Human beings have been thinking about and counting time for thousands of years. The first time-keeping machines used sand, water or the position of the Sun in the sky to mark out the passage of time. These days, we use clocks and watches for telling the time. But however we do it, our measurement of time is based on the movement of our planet Earth in relation to the Sun.
Numbers are useful for counting and measuring things. We use them all the time, even when we’re not thinking about maths. For example, I use them every day, for telling the time, cooking, exercising and driving my car.
Normally when we count, we start at zero and count upwards in whole numbers: one, two, three, and so on… But what happens if we count down from a bigger number – do we have to stop when we get back to zero?
This question was asked on a cold Winter’s day. The water in the bird bath had frozen and I used hot water from the kettle to thaw it so the birds could drink. When I explained to my 6-year-old that water freezes at zero degrees Celsius, she wondered if that was the coldest that things can get. But it isn’t – in fact some things can get much, much, much colder!
So what happens when things get hot or cold and how do we measure temperature?