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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Watch on YouTube How does an iron remove wrinkles from clothes? The heat forces the cellulose chains to lie straight. People started wearing clothes about 170,000 years ago. Scientists worked this out by looking at the evolution of lice that live on humans. Lice that live on clothes are different from the lice that live
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Watch on YouTube What makes things sticky? When the molecules in two substances are attracted to each other things become sticky. The stickiness of an adhesive and the stickiness of something like maple syrup are a little bit different from each other. Let’s look at the stickiness of glue, adhesive tape, and maple syrup. There
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Watch on YouTube When did people start wearing wedding rings? Wedding rings have been found dating back as far as 4000 BC. Rings were first used in Egypt by the pharaohs to represent eternity. A ring has no beginning and no end. It also reflects the circular shape of the sun and the moon, both
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Watch on YouTube Why is carbon-based life common? Because carbon can bond with many different elements to allow chemical reactions to happen. On our planet all living things contain carbon. There may be lifeforms on other planets that are made of different elements but on Earth, everything uses carbon in one way or another. Plants,
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