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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Where did Roman numerals come from? Despite their name, Roman numerals evolved from an Etruscan system of counting, which may possibly have come from Ancient Greece. The Romans popularized the system and left it for us to see, which is why we gave it their name. Here is a refresher course in Roman numerals. I
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Why did the first electrical plugs go into light sockets? The first electrical plugs screwed into light sockets because early homes were wired mainly for lighting, and the light socket was often the only convenient place to tap the electricity. These days, every house will have multiple electrical outlets in most rooms. We will be
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Why do screws tighten clockwise? Most screws tighten clockwise probably because the majority of people are right-handed. That might sound like something that must have been decided thousands of years ago, but the direction of screws has only really been standardized since the 19th century. That was when machining improved to the point where a
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Who invented the first eye chart? The first widely used eye chart was invented by a Dutch ophthalmologist called Herman Snellen. The earliest eye charts were invented in the early 19th century, but Snellen’s chart was the one that became the standard. The majority of people will have used an eye chart at some time.
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Why do some lakes have no fish? Some lakes have no fish because the environment they are in, or the composition of the water, is too harsh for the fish to survive. A related question is how some completely isolated lakes have fish. Most lakes contain fish. The few that don’t are usually too inhospitable
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