How do we know Earth has an iron core? Experts think that the Earth has an iron core because of the way seismic waves pass through the Earth, its overall density, the abundance of iron, our magnetic field, and laboratory experiments. Before we begin, scientists do not know with absolute certainty that the Earth has […]
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What were the Pinkertons? The Pinkertons were a detective agency set up by Allan Pinkerton in 1850. The Pinkerton detective agency started out with fairly noble goals, but it ended up becoming hired muscle for large corporations. In the 20th century, the company shifted more toward private security, and it still exists today as Pinkerton,
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How do planes take off and land on an aircraft carrier? Planes take off on an aircraft carrier by using a catapult, and they land by using a hook. Planes take off from an aircraft carrier by using a high-powered catapult. To fly, an airplane needs to have air move over its wings at a
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Who were Currer, Ellis, and Acton Bell? They were the pseudonyms used by Charlotte, Emily, and Anne Brontë. The Brontë sisters are known for some of the most famous novels in the English language. Charlotte Brontë wrote four novels, the most famous of which is Jane Eyre. Emily Brontë wrote Wuthering Heights. Anne Brontë wrote
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What is tuberculosis? Tuberculosis (TB) is a contagious, airborne bacterial infection caused by Mycobacterium tuberculosis. If you have read any books set in Victorian London, you will have seen character after character die of “consumption.” It killed two of the famous Bronte sisters, as well as two of their other sisters and their brother. In
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Why is Mercury so difficult to visit? Mercury is difficult to visit because, among other things, it is moving so fast, it is very close to the Sun, and it doesn’t have an atmosphere. Out of all the planets in the solar system, Mercury has been visited the least. So far, Mars is the most
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What was the first police force? The first police force that we would recognize as similar to our own was most likely the Metropolitan Police, started by Robert Peel in 1829. It was the first full-time, professional, centrally organized police force for a major city, built around preventive patrols, with paid officers under a standardized
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What was the first mass-produced consumer product? Items have been produced in large numbers for thousands of years, but most were not everyday goods for ordinary people to buy. The first true mass-produced consumer products were most likely textiles in the late 18th century. There is evidence of large-scale production going back thousands of years.
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Why do we use feet and inches, and why do eggs come in dozens? Why do we use feet and inches, and why do eggs come in dozens? We basically use feet as measurements because everybody has feet, and eggs come in dozens because it is easier to divide them up. Imperial measurements are slowly
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Why do printers use CMYK not RGB? Printers use CMYK because paper reflects light rather than emitting it. CMYK stands for Cyan, Magenta, Yellow, and Black. Black has the letter K because it stands for “key plate.” In old-style printing, the key plate was the plate that carried the most detail and definition. Because most
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