If there were no trees, would there still be enough oxygen for us to breathe?

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Air is mostly made up of a gas called nitrogen. But about one-fifth of the air (21%) is oxygen – the gas our bodies use when we breathe.

All living things need oxygen in order to stay alive but plants, algae and a group of bacteria called cyanobacteria, can also make oxygen. These plants, algae and cyanobacteria make more oxygen than they use and the extra oxygen goes back into the air. So, the oxygen is sort-of recycled, rather than used up.

Plants like trees use their leaves to make oxygen. But what if there were no trees left on Earth – would there still be enough oxygen in the air for us to breathe?

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Is oil really made of dead dinosaurs?

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Oil is a type of fuel, which means that it is something we use to make energy. We burn oil to heat buildings and to make electricity, and we use it to make petrol and diesel for cars and other vehicles. There are also some rather surprising uses for oil, including chewing gum, lipstick and guitar strings!

But what is oil? How is it made? And does it really come from dead dinosaurs?

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Can you have backwards numbers?

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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?

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How is light made?

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Light is all around us. The Sun shines on the Earth every day and we use electric lights or candles to light our homes, schools and workplaces. We use torches or streetlights when we are out and about at night and build fires for light and warmth when we go camping. Even in the middle of the night, there is some light from the stars in the sky.

But one of my daughter’s schoolfriends asked me how light is made. And her brilliant question made me think about natural and man-made light sources.

So, let’s find out more about light – what it is and how it is made…

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Why do cats bury their poo?

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Our cat, Fishfingers, goes outside several times a day so that he can wee and poo in the garden. When we first got him, we put a litter tray (a plastic tray filled with bits of clay or sawdust that he could use as a toilet) inside the house, just in case he needed to use it. My 6-year-old noticed that if Fishfingers did use the litter tray, he would then spend ages afterwards trying to cover up his wee/poo with the clay or sawdust.

But why does Fishfingers try to cover up his wee/poo? Let’s find out about cat behaviour to work out the answer:

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