Why were spices so valuable in the past? You can buy a jar of spices today for a few dollars, but for a large part of history, some spices were extremely valuable. A few were even said to be worth their weight in gold. This was generally down to how hard they were to get, […]
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How does a spring work? A spring works by storing mechanical energy when it is deformed and then releasing that energy when it returns to its original shape. Springs don’t have to be metal, but in human-made springs, metal is probably the most common material. There are natural springs as well. The tendons in a
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What is the watershed? A watershed is a turning point or a dividing point between two times or events, although the word originally comes from geography. In geography, a watershed is an area of land that drains water to a specific point. Another word for a watershed is a drainage basin. It is basically the
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How do escalators move at almost the same speed when they are empty and when they are fully loaded? Escalators can move at almost the same speed no matter how much weight is on them because their motors are designed to run at a steady speed and produce more torque when the load increases. Chairlifts
What is highly enriched uranium? It is uranium that contains 20% or more uranium-235, which is the type of uranium most useful for a sustained nuclear chain reaction. Uranium is a fairly common element that can be found in rocks, soil, and water. It is not as rare as many people probably imagine. There is
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What causes travelers’ diarrhea? Travelers’ diarrhea is usually caused by bacteria, viruses, or parasites that get into food or water. The most common causes are bacteria, especially certain types of Escherichia coli, or E. coli. Travelers’ diarrhea is something that affects a lot of people after they have been traveling for a few days or
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How do storm drains work? Storm drains work by directing rainwater from roads, sidewalks, roofs, and streets into underground channels, where the water can be controlled and carried away. Before there were cities, storm drains were obviously not necessary. When it rains in nature, the water hits the ground and either soaks into the soil,
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Why are British people called Limeys and Poms? British people are called Limeys because of the citrus juice British sailors drank to prevent scurvy, and they are probably called Poms because of Australian rhyming slang connected to the word immigrant. There are many names for British people around the world. Some of them are affectionate
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How did hinges evolve? The very first hinges were probably simple wooden or stone pivots, and they slowly evolved from there. We probably don’t pay much attention to hinges, but we use them multiple times every day. Doors, cupboards, car doors, garage doors, and even the arms of glasses and sunglasses all have hinges. They
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What causes traffic jams? The biggest cause of traffic jams is obviously the volume of traffic, but, in order of importance, they are caused by bottlenecks, traffic incidents, bad weather, road construction, poor signal timing, and other factors. Obviously, the main cause of traffic congestion, irrespective of the other reasons, is the volume of traffic
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