What is the range of a cell phone tower? The average maximum range of a phone mast is about 40 km, 25 miles. How does a cell phone tower work? Cell towers have detectors and transmitters to receive and transmit radio signals. When you want to look at a website on your phone, my site […]
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How do you get water to the top of a skyscraper? Water is pumped up to a series of tanks at different heights. Early pumps were usually suction pumps and a suction pump cannot be used to get water to the top of a skyscraper. A suction pump cannot pump water to a height greater
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What is a hollow-point bullet? It is a bullet that expands on impact, causing more damage, without going all the way through the target. With a hollow-point bullet, the tip is literally hollowed out. A cartridge has four parts. It has the case, which holds everything together. It has the primer, which is struck by
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Why did early humans leave Africa? They were probably forced out by climate change, but they could have left because of their rising intelligence. Let’s look at the evidence for why paleontologists believe humans developed in Africa and then look at why they left. Humans probably separated from the common ancestor we share with other
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Why do soldiers break stride on a bridge? So that the vibrations don’t make the bridge collapse. This rule was introduced by the British Army in 1831. On 12th April 1831, the 60th Rifle Corps were returning from a military exercise and they crossed over the Broughton Suspension Bridge, which had been built five years
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How does a canal lock work? By using gravity to increase the amount of water in the canal and rise the boat. There are two different reasons why canals need locks. The first is that canals are bodies of running water and so they have an upstream and a downstream, giving them a current. They
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What is cotton? Cotton is a fiber that grows around the seeds of the cotton plant. About 27 million tons of cotton is produced every year. India is the largest producer, with 6.1 million tons, and it is followed by China, the USA, Brazil, and Pakistan, in that order. A standard t-shirt requires approximately 226
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Why do we say “born to the purple”? What is Tyrian purple? We say that someone who is born into a royal or powerful family is “born to the purple” because Tyrian purple was an incredibly expensive color that only wealthy and powerful people could afford. The dye for Tyrian purple was made from the
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Is an Olympic gold medal really made of gold? The gold medal the winners at the Olympics get is only 7.5% gold. It is 92.5% silver with only a gold-plating of about 6g. With 6g of gold in a medal, the value of the medal would be about $800 if sold for its precious metals.
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Why is oil measured in barrels? Oil is measured in barrels because that was the size of a wine barrel in 1866. Nobody really knows when barrels were invented, but there is a picture of a wooden barrel made to measure wheat on the wall of the tomb of the Egyptian high official, Hesy-Ra, from about
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