How could a whistle get free phone calls? Old telephone routing equipment worked on sound at a specific frequency. Some whistles blew at exactly the same frequency and could be used to trick the phone equipment. The people who were cheating the phone system called themselves “phreaks”, which was a combination of “phone” and “freak”. […]
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How do drones hover? Drones hover by using a mix of sensors to adjust their rotor blades. The majority of commercially available drones have four sets of rotor blades, one on each corner. This makes them much easier to control at low speeds and much more stable. The military have drones like this, but they
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What is junk DNA? Junk DNA is DNA that doesn’t seem to do anything. It is not part of our coding DNA. DNA is in the cell nucleus of all of our cells. DNA stands for deoxyribonucleic acid. The deoxyribo part is sugar. The nucleic acid part is a long chain like molecule. Inside the
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Why was there a tulip bubble? There was a tulip bubble in Holland and across Europe in the 16th century because tulips were rare and because people didn’t want to lose out on an opportunity to make money. The tulip bubble, also called tulipmania, is a good showcase for human nature. It shows how people
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Why were there so many revolutions in 1848? There are a number of factors why there were so many revolutions in 1848, from economics to climate. Starting in 1848 and going through to 1849, there were revolutions in over 50 different countries and principalities. These were mostly in Europe, but countries in South America were
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What do mitochondria do? Mitochondria produce almost all of the chemical energy that cells need for all of their functions. Without the mitochondria, we can’t do anything. The word “mitochondria” was created in 1898 by a microbiologist called Carl Benda. He took the Greek word “mitos”, which means “thread”, and “khondrion”, which means “little granule”.
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Who was first to the North and South Poles? The first person to reach both the North and South Poles was Roald Amundsen. Although, he didn’t reach the North Pole by foot. The first person to reach the North Pole by foot was Wally Herbert. Let’s look at the North Pole first. There are two
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How does an iron lung work? An iron lung works by creating a space of negative pressure to inflate the lungs. You have probably seen images of people in an iron lung. It was typically a cylindrical contraption, slightly longer then the height of the patient. It had a hole for the head to stick
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What was operation Paul Bunyan? Operation Paul Bunyan was an operation by American forces in 1976 to cut down a poplar tree in the Korean Demilitarized Zone in retaliation for the killing of two United Nations Command officers by North Korean soldiers. The operation was named after Paul Bunyan who was an American legend. He
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What was the Green Book? The Green Book was a list of places that would serve African Americans when they travelled around the USA between the 1930s and the 1960s. It was written by Victor Hugo Green, so he named it the Green Book after himself. The full name of the book was “The Negro
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