How big could a plane or helicopter be? Theoretically, there is no limit so long as there is a strong enough material and enough thrust can be produced. Practically, there are no materials strong enough to make planes or helicopters much larger than they already are. The largest helicopter in the world at the moment […]
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What is the difference between volts, amps, ohms, and watts? Volts measure the difference in electrical force between two points. Amps measure the flow of electricity. Ohms measure the resistance of the material. Watts measure electrical power. The volt is named after Alessandro Volta, who built the first electric battery. Volta lived from 1745 to
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What are gallstones? They are hardened deposits of bile that can form in the gallbladder and cause problems. We need to start by looking at what the gallbladder is and what it does. The gallbladder is quite small and it is located just under the liver, at the bottom of the stomach. It is about
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What is fool’s gold? It is most commonly pyrite, which has a similar appearance to gold. The expression “fool’s gold” came into existence in the 1820s. The knowledge that there were other metals that looked like gold has probably been around for centuries, but it was only in the 1820s that gold rushes became a
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How did humans spread across the world? Generally, early humans moved around the world using land bridges or ice bridges. Occasionally, they may have used boats. The first migration happened before home sapiens had even evolved. Homo erectus evolved in central Africa at least three million years ago. This can be attested to by the
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What happens if you drink too much water? Your brain can swell up and you can have seizures and possibly even die. Overhydration is the opposite of dehydration, and just like dehydration can be fatal, overhydration can be as well. However, it is much harder to be overhydrated than it is to be dehydrated. To
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What causes acid rain? Acid rain happens when water molecules in the atmosphere encounter sulfur dioxide or nitrogen oxide. Acid rain was a big problem in the USA and European countries during the 1980s and 1990s, but we don’t hear so much about it anymore. Has the problem been solved, or has it just shifted
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How does carbon dating work? Carbon dating allows scientists to estimate the age of something by counting the number of carbon-14 atoms that are left. Carbon-14 is created in our atmosphere and is absorbed by all living organisms. It is created when cosmic rays impact nitrogen atoms in our atmosphere. A cosmic ray is a
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Why was the Cold War called a “cold” war? It was called a “cold” war because there were no direct military confrontations between the United States on one side and the USSR on the other side. This is compared to World Wars 1 and 2 which had gone before and were hot wars because there
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Why don’t army ants make nests? Army ants can clear an area of insects and food in a few days, so they have to keep on the mood to find more food. Most species of ants build complex nests that have interlocking tunnels and chambers for different purposes. They have places to keep their larvae,
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