How does a smartwatch measure pulse and blood oxygen levels? A smartwatch measures both pulse and blood oxygen levels by shining different colored lights through your skin and into your blood vessels. These days, smartwatches have more and more functions, and many of those functions are to do with health. Two things they can do […]
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What was the brightest supernova? It depends on what we mean by “brightest”. The brightest supernova that records exist for was SN 1006, which was visible from April 30 to May 1, 1006 (hence its name). The SN stands for supernova. There have been far more massive supernova that we couldn’t see from Earth. A
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What is the Zeigarnik Effect? The Zeigarnik Effect is the idea that our brains remember unfinished tasks more easily than finished ones. It often goes hand in hand with the Ovsiankina effect. Have you ever noticed that you spend a lot of time thinking about things you have to do at work? Projects, upcoming tasks,
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What was the Spanish Inquisition? The Spanish Inquisition was a judicial institution, run as a royal court, that investigated and prosecuted heresy and religious nonconformity in Spain (and later the Spanish Empire), and was used by the monarchy to enforce Catholic religious conformity. “Inquisition” just means “inquiry.” The Catholic Church had investigated suspected heresy long
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Why do beans cause gas? Beans cause gas because of the complex sugars and fiber that they contain. Beans are the seeds produced by plants in the legume family. A lot of them are edible, but not all of them. Humans cultivate and make use of many different kinds of beans. Beans are seeds, but
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Where do the expressions red herring, read the riot act, white elephant, and pay through the nose come from? A red herring is a clue that ends up not being relevant to the crime, or purposefully set to distract the police. The main theory of its origin is that it came from training dogs to
Who came up with the idea for the periodic table? The periodic table was first made by a Russian chemist called Dmitri Mendeleev in 1869. You have definitely seen the periodic table of elements. Currently, it has 118 elements on it. The first 94 of those are naturally occurring elements and the other 24 have
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Why is fire hot? Fire is hot because thermal energy is released from the materials when chemical bonds are rearranged during a combustion reaction. New, stronger bonds form and the energy difference comes out as heat and light When you burn most fuels, you are releasing the chemical potential energy that they have stored inside
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What is rabbit starvation? Rabbit starvation is what can happen when a person eats almost nothing except very lean meat for a prolonged period. A person can feel full, but still become malnourished because the diet is extremely high in protein and extremely low in fat and carbohydrates. The name “rabbit starvation” comes from rabbit
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Will jumping just before an elevator crashes save you? Probably not. Even if someone managed to jump at the last second, they would still be moving downward at almost the same speed, so the change in the impact would be tiny. The real danger in a crash is not just “speed,” but how quickly that
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