What is highly enriched uranium? It is uranium that contains 20% or more uranium-235, which is the type of uranium most useful for a sustained nuclear chain reaction. Uranium is a fairly common element that can be found in rocks, soil, and water. It is not as rare as many people probably imagine. There is […]
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Why does friction produce heat? Friction produces heat because mechanical energy has to go somewhere, and some of it is converted into the random movement of atoms and molecules, which is heat. Sometimes we need friction to produce heat and sometimes we don’t want it to. If you have ever been out in the cold
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What is tuberculosis? Tuberculosis (TB) is a contagious, airborne bacterial infection caused by Mycobacterium tuberculosis. If you have read any books set in Victorian London, you will have seen character after character die of “consumption.” It killed two of the famous Bronte sisters, as well as two of their other sisters and their brother. In
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What does E = mc² mean? E = mc² means that mass and energy are two ways of describing the same physical thing. In everyday life, mass feels like “stuff” and energy feels like “activity,” but Einstein showed that they are connected. If a system loses energy, it also loses mass. If it gains energy,
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What did Marie Curie win two Nobel Prizes for? She won the Nobel Prize in Physics in 1903 for her research in radiation (shared with her husband), and she won the Nobel Prize in Chemistry in 1911 for discovering radium, polonium, and isolating radium. Marie Curie is not the only person to have won two
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Are all snowflakes really different? Theoretically, yes, all snowflakes are different, but it is an issue of probability, and there is obviously no way to know for sure. Snowflakes form when the air is cold enough for water droplets to freeze. It is very difficult for them to freeze on their own; it is much
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What is a geothermal heat pump? A geothermal heat pump is a way of heating and cooling buildings by exchanging their heat with the ground. Natural objects obviously gain and lose heat depending on the amount of sunlight, what they are made of, the weather, where they are, and a whole host of other conditions.
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Why does metal feel colder than wood? Metal feels colder than wood because metal has a far higher thermal conductivity than wood does. There are two things we need to look at here: how metal conducts heat, and how our hands sense temperature. Heat is not actually a thing. Heat is a process. It is
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How does a thermal imaging camera work? A thermal imaging camera works by detecting infrared radiation and then processing it into an image that can be displayed on a screen. Everything on Earth can absorb heat or radiate heat. Mammals, such as us, create our own heat by burning the food we eat to make
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Why can’t I walk through a wall? We can’t pass through a wall because of the Pauli Exclusion Principle and because of electromagnetic repulsion. If you think about it on the microscopic level, there is a huge amount of space between the atoms in anything. They are like planets in the solar system. So, if
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