How would an invisibility cloak work? There are basically three ways you could make something invisible. You could use camouflage to hide it. You could use cameras to project the view behind the object in front of it. Or you could manipulate light so that it bends around the object being hidden. We have all […]
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How do owls fly silently? Owls have specialized feathers that allow them to fly silently. If you live outside of a city, you may have heard owls hooting at night. You may even have heard them if you live in a city, because these days there are a lot of urban owls. It is not
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When did people start using surnames? People started using surnames at different times in different countries. In Europe, surnames started in the 11th century. I am from the UK, so I am going to begin by looking at the origin of surnames in Europe and then look at other parts of the world. The word
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What is compost? Compost is a mix of materials that can fertilize plants and improve the condition of soil. It is also an excellent form of waste management. It is difficult to get accurate figures on how much food is wasted every year because there is no true way of measuring it. I live in
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What are fiber lasers? Fiber lasers are lasers in which the light is generated and amplified inside an optical fiber whose core has been doped with tiny amounts of rare-earth ions (such as ytterbium or erbium). The laser beam then comes out of the end of the fiber, which makes the system compact, efficient, and
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When did telephone operators become obsolete? The tools to make them unnecessary were invented in 1888, but telephone operators kept working, in one form or another, well into the late 20th century – and the job has still not completely disappeared. Alexander Graham Bell is usually named as the inventor of the telephone, but he
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What is a whale fall? A whale fall is when a whale dies and falls to the bottom of the ocean, providing a sudden food source. A whale fall has different stages that can last for several years. A dead whale can provide an enormous amount of food for other sea life. It is difficult
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What is a fog net? A fog net is a very fine mesh used for pulling fresh water out of fog. People get their water from a whole range of sources. They could be reservoirs, aquifers, rivers, desalination plants, or, sometimes, having it shipped in by truck. A lot of places are experiencing water shortages,
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How do green roofs help? Green roofs help by cooling cities and by insulating houses. They absorb heat, absorb rainwater, cool the air around the building, and act as insulation as well. I suppose the first thing to look at is the fact that the plural of roof is roofs, not rooves. Apparently, rooves is
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How do airports sort bags? At its simplest, airports sort bags by scanning a ten-digit barcode on each bag and automatically controlling which conveyor belt the bag travels on to get to the plane it needs to be loaded on. If you have ever had a piece of luggage go missing, you may have gone
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