Why do tattoos stay in the skin forever? Because the particles of ink are too big for the body to absorb and expel. When you have a tattoo, the tattooist uses a needle to put ink particles into your skin. Skin has three layers, and the ink is injected into the middle layer, the dermis. […]
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How does insulation in the home work? By slowing down the movement of heat energy out of the house or into the house. The idea of insulation is to stop your house getting cold in the winter or hot in the summer. If you live somewhere that is cold in winter, you have to use
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Who invented the slide rule? Willian Oughtred in 1622. I think, first, I need to look at what a slide rule is because not many people under 60 will have ever used one. These days, if we want to do complex calculations, we can just plug them in to our phone and get the answer
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What are moles, freckles, and birthmarks? Moles are caused when pigment-producing cells grow in a group. Freckles are caused when your skin cells produce too much melanin. Birthmarks are caused when blood vessels don’t form correctly or when the cells that produce pigment grow too much. Almost everybody has moles. By moles, I obviously don’t
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Watch on YouTube Why is carbon-based life common? Because carbon can bond with many different elements to allow chemical reactions to happen. On our planet all living things contain carbon. There may be lifeforms on other planets that are made of different elements but on Earth, everything uses carbon in one way or another. Plants,
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What is the difference between socialism and communism? They are sometimes confused as being the same thing, but socialism and communism have some key differences. In socialism, all citizens own and share equally in all resources and wealth. In communism, all property and economic resources are owned by the state, which is entrusted to share
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Do the gulags still exist? Technically no, but actually yes. The gulag is not actually a place. We use the expression gulag to refer to a Russian prison, but it is really the name of the government agency that was in charge of the forced labor camps during the Soviet era. The word gulag is
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What is the difference between a castle, a fort, and a palace? A castle is a fortified building constructed for the nobility. A fort is just a fortified building. A palace is a large house built for royalty, or very wealthy people. Forts appeared long before castles. A fort is a fortified building and the
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What is the difference between DVD and Blu-Ray? Their age, size, quality, audio, and the disc reading technology. DVD is an older technology than Blu-Ray. The technology used to read DVDs was invented in 1958 by David Paul Gregg, an American engineer, and James Russell, an American inventor. Gregg invented a way to record video
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Why don’t shipping containers fall off ships? Well, they do sometimes, but generally they are fastened down with lashing rods. There are almost 5,500 container ships in the world and they ship over 11 billion tons of cargo around the world every year. The size of the ships has also increased year by year. The
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