Why do we get headaches? There are many theories, but nobody actually knows. There are 200 different types of headaches, but they are divided up into primary and secondary headaches. Primary headaches are headaches that aren’t caused by a disease or damage to the brain. Secondary headaches are caused by a disease or damage to […]
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How does a rocket engine work? Rocket engines work because of Newton’s third law of motion. Newton’s third law of motion states “to every action there is always opposed an equal reaction; or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.” Or, in other words, for
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What makes us itch? Itching is caused by the release of the chemical histamine. There are different types of itch. Almost all animals have an itch and scratch response. Bears scratch themselves on trees and dolphins scratch themselves on rocks, or at the bottom of their tank if they are in captivity. It is an
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Is irradiated food safe? Irradiating food kills off all of the bacteria, gives the food a fresher taste than other preservation methods, and doesn’t make the food radioactive. Ionizing radiation was discovered in 1895. Wilhelm Röntgen discovered that rays coming off a vacuum tube could penetrate a screen and react with a barium solution. He
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Why does UHT milk last so long? UHT stands for Ultra High Treatment and it is heated at 138℃ for 2 seconds to kill all the bacteria. All milk you buy in the shop has been pasteurized. In most countries it is illegal to sell unpasteurized milk because of the dangers. Unpasteurized milk can contain
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Where did Arabic numerals come from? They evolved from a writing system created in India in the 3rd century BC. The first evidence of prehistoric humans using numbers comes from a bone dated from 43,000 years ago. It is the Lebombo bone and it is a baboon femur with 29 notches carved into it.
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Why do women live longer than men? There are many reasons, but having two copies of the same sex chromosome and testosterone might be the most significant. Obviously, both men and women age. Their bodies undergo similar changes that ultimately result in death. However, across the world, women tend to live on average 8%
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How do you build a tunnel underwater? You can either build the tunnel above ground in pieces and lower it into the water, or you can dig the tunnel underground. Humans have been making tunnels for thousands of years. The art of tunneling probably started when prehistoric people wanted to make their caves bigger.
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What did the last emperor of china do later in life? He spent the last years of his life working as a road sweeper, a gardener, and an editor. The last emperor of China was Aisin-Gioro Puyi. He became emperor in 1908 at the age of two when his half-uncle died without children.
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How much of your liver can you live without? Surprisingly, you can survive with only 25% of your liver. Where is your liver and what does it do? The liver sits just above your stomach. It weighs about 1.5 kg and is the largest organ in the body if you don’t count the skin.
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