Watch on YouTube Why is the Grand Canyon so deep? Because of the power of the Colorado River, the amount of water in it, the arid climate, and the rocks it is made of. The Grand Canyon carves through the Colorado Plateau. It is 446 km long, 29 km wide, and 1,857 m deep at […]
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Watch on YouTube What will happen at the end of the universe? There will either be a Big Crunch, a Big Bounce, a Big Rip, or a Big Freeze. The universe is thought to be 13.7 billion years old. This has been calculated in two ways. The first way is to find the oldest stars
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Watch on YouTube Why does blood show up under UV light? Because it absorbs all of the light and appears completely black. When we watch crime movies, the police often use a black light to show stains at the murder scene. Well, a black light will make many bodily fluids glow, but it won’t make
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Watch on YouTube Why do stick insects look like plants? They have evolved to resemble the plants they live and feed on, in order not to be eaten by birds and other animals. Stick insects are a wonderful example of natural selection at work. There are over 6,000 species of stick insect in the world,
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Watch on Youtube Why is 0 longitude in London? It was used by more than two-thirds of the world’s ships and the USA had decided to use it. The line that runs through Greenwich in London is known as the prime meridian, meaning it is zero degrees longitude. The Earth is divided up into 360
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Watch on YouTube How much wind does a wind turbine need? A wind speed of roughly 11 km/h. Wind power has been used for over 2000 years. The windmill was invented in the 7th century in Persia and wind power was harnessed to grind grain. The wind could do the work of a herd of
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Watch this on YouTube When did cave paintings first appear? The oldest cave painting found so far is from 50,000 years ago but the oldest known prehistoric art was from 73,000 years ago, painted on a rock. There is a lot more cave art to be found than art outside caves because the caves protect
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How does a 3D printer work? There are four different methods of 3D printing. Fused deposition modeling, stereolithography, digital light processing, and selective laser sintering. 3D printing is becoming more popular in the manufacturing process these days for many reasons, not least because it is additive manufacturing as opposed to subtractive manufacturing. When things are
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Watch on YouTube Why are deserts cold at night? The sand reflects the heat up and the air cannot hold the heat in. Deserts have very high temperature extremes. The Sahara Desert, for example, has an average daytime high of 38 ˚C and an average nighttime low of 4 ˚C. If you are stuck in
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Watch on YouTube How quickly do bones biodegrade? It depends on what kind of soil they are buried in, but from 6 years to thousands of years. The bones we have of dinosaurs are not actually bones but fossils. If a dinosaur dies in the right conditions, minerals can replace the calcium in the bones,
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