How do LED lights produce different colors? By using different materials that produce light at different wavelengths. LED stands for Light Emitting Diode and they are very different to regular light bulbs. A lightbulb produces light by passing an electric current through a very thin metal filament. This filament has to have a very high […]
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When did we start using tarmac on roads? Tarmac (asphalt) only really became popular once the motorcar was invented. Once you know that, it seems obvious, but it never really occurred to me. We have had roads for thousands of years longer than we have had tarmac. The first roads were created when people started
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Why is glass transparent? Glass is transparent because light photons don’t have enough energy to excite the molecules in the glass. There are two things we need to look at here. What is glass and what is light? Glass is a non-crystalline amorphous solid. There’s a bit to unpack there. Non-crystalline refers to the structure
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How quickly are the continents moving apart? Our continents are moving apart at a rate of 2.5 cm every year. The surface of Earth is divided up into 15 tectonic plates. There are seven major plates and eight minor ones. The major plates are named after the continents that are on them: African, Antarctic, Eurasian,
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Can the Mona Lisa ever be sold? The Mona Lisa, by Leonardo da Vinci, can never be sold because it is owned by the people of France. There was a time when the Mona Lisa was owned by a single person. In fact, the painting was owned by a few single people, and could have
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What is & called and why? The symbol “&” is called the ampersand, which actually means “and, by itself, and”. It is also a shorthand version of the Latin word “et”. These days, we use the ampersand as a symbol for “and”. It is also used in programming language. It is not generally acceptable to
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What is a Scramjet? It is an air breathing jet engine that works at supersonic speeds. Right. There are three questions we need to unpack here. How does a jet engine work? How does a ramjet engine work? How does a scramjet engine work? A jet engine has fan turbines at the front of it
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How can paints be different colors? To make different colored paints, you need to add different materials for color pigments because different particles reflect different wavelengths of light. Our eyes pick up reflected light using photoreceptors that are sensitive to different wavelengths. These then travel to our brain, which associates them with a color. For
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When did people start wearing wristwatches? People started wearing wristwatches during World War 1. Clocks had been around for some time before the first watches appeared in the 15th century, in Europe. Several advancements were necessary before clocks could be made small enough to be a watch. Clocks generally worked by using a system of weights
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Why does a chicken’s head stay perfectly still when you move its body around? Because chickens cannot move their eyeballs in their eye socket and because they don’t have a vestibulo-ocular reflex. Our heads (humans) are pretty much constantly moving, yet we can see perfectly well. This is all thanks to the vestibulo-ocular reflex which
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