Why can’t you open an airplane door mid-flight? You can’t open the door while an airplane is flying because of pressure, the design of the door, and because of safety mechanisms. Large planes, such as the 747, have several doors on each side of their fuselage. Each door appears to be closed with only a […]
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When did cigarettes become mainstream? Cigarettes increased in popularity after their manufacture was automated, but they became mainstream after World War 1. Tobacco wasn’t known in Europe until the Spanish brought it back from South America in the 15th century. Before tobacco arrived, people in Europe had other drugs to smoke, but they were more
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How does slipstreaming work? Slipstreaming works because one vehicle drives closely behind another so that it can ride in the low-pressure wake that follows the first vehicle, reducing the air resistance and reducing the amount of power needed. Unless you are moving in a vacuum, you are going to come up against air resistance. We
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Why is Boxing Day called Boxing Day? Boxing Day is most likely called Boxing Day because of the tradition of wealthy families giving boxes of gifts, money, or leftover food to their servants and tradespeople. However, it could also come from churches giving charitable boxes to people in their congregation. It could be a combination
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Why do we write Xmas for Christmas? The “X” isn’t an X from the Latin alphabet; it is from the Greek alphabet, and it is “chi”, the first letter of the Greek word Christos, meaning Christ. I didn’t actually know until I started researching this topic today that some people think Xmas is an attempt
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Why does old paper turn yellow? Old paper turns yellow because lignin and cellulose break down. Most things in our world fade with time. The most common culprit is ultraviolet light. If you have a photo on your desk or a nice painting on your wall, over time, it will lose its vibrant color. And
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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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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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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 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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