What causes a stroke? There are different types of strokes, but the most common is an ischemic stroke and it is caused by a blockage in one of the blood vessels in the brain. The brain has a huge oxygen requirement. It is only 2% of your bodyweight, but it uses 15 to 20% of […]
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Too busy to read? Watch on YouTube. When did archaeology start? Archaeology started as a discipline in the 18th century. Before the beginning of archaeology as a discipline, there were two types of people that were interested in things from past civilizations. Those were people who liked to collect artifacts, and people who wanted the
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Too busy to read? Watch on YouTube Why do ducks float? They float because of their center of gravity, their hollow bones, the air in their feathers and air sacs, and the oil on their feathers. Whether or not something floats has to do with the object’s density and the buoyancy of water. Water has
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Too busy to read? Watch on YouTube Are ants and termites the same thing? No. They belong to different insect orders. Termites are from the Isoptera order and ants are from the Hymenoptera order. Termites and ants are easily confused and they have a lot of similarities, but they have a lot of differences as
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Watch this on YouTube Is Earth an open or closed system? It is both. For some things it is open and for others, it is closed. Earth is an open system for energy. Most of the energy on Earth comes from the sun. Energy enters Earth from outer space as well, but the sun is
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Watch on YouTube Why were the Terracotta Warriors buried? They were buried to protect Qin Shi Huang, the first emperor of China, in the afterlife. Qin Shi Huang was a very influential ruler of China. He was the first emperor of a unified China and a lot of things were begun in his reign. He
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Watch on YouTube Why is Broadway so long? Before it became a road it was originally the Wickquasgeck trail. Broadway is a street that runs through Manhattan. It is famous for having many of New York’s theaters on it. It is actually much longer than people think and stretches for 53.2 km. It starts at
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Watch on YouTube How do facial expressions work? There are 20 muscles in the face that can be moved in different combinations. There are two kinds of facial expressions: voluntary and involuntary. A lot of study has gone into reading facial expressions and there are many theories about whether they reveal inner thinking or not.
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Watch on YouTube Are Inner and Outer Mongolia separate countries? Outer Mongolia is the country of Mongolia and Inner Mongolia is a part of China. Outer Mongolia is known as Mongolia and has an official language of Mongolian, although many people also speak Russian. It has a population of a little over 3 million people
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Watch on YouTube How was the meter (metre) defined? In 1791 it was defined as one ten-millionth of the distance from the equator to the North Pole. The word “meter” comes from Greek and means “to measure” or “to count.” That’s why the “meter” in speedometer and altimeter doesn’t mean the unit of distance. The
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