What is the difference between volts, amps, ohms, and watts? Volts measure the difference in electrical force between two points. Amps measure the flow of electricity. Ohms measure the resistance of the material. Watts measure electrical power. The volt is named after Alessandro Volta, who built the first electric battery. Volta lived from 1745 to […]
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What causes acid rain? Acid rain happens when water molecules in the atmosphere encounter sulfur dioxide or nitrogen oxide. Acid rain was a big problem in the USA and European countries during the 1980s and 1990s, but we don’t hear so much about it anymore. Has the problem been solved, or has it just shifted
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How does carbon dating work? Carbon dating allows scientists to estimate the age of something by counting the number of carbon-14 atoms that are left. Carbon-14 is created in our atmosphere and is absorbed by all living organisms. It is created when cosmic rays impact nitrogen atoms in our atmosphere. A cosmic ray is a
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How quickly does your blood regenerate after you donate it? The blood volume will be back in 48 hours, but it will take four to eight weeks for the red blood cells to regrow. When people donate blood, they usually give about 450 ml, which is about a pint. Depending on your size, that is
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What is a superconductor? It is a state of matter for a material where there is zero resistance to electricity. We need to start by looking at what electrical resistance is. Electrical resistance is, rather obviously, a resistance to the flow of electricity. An electric current results when electrons flow from an area with a
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Why does entropy happen? Entropy happens because there are vastly more ways a system can be in disorder than it can be in order. Entropy is explained in the second law of thermodynamics. It says that the state of entropy of an isolated system will always increase over time. It has been rewritten since it
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Why is carbon dioxide the main greenhouse gas? Carbon dioxide is the main greenhouse gas because it absorbs more heat than other gases. When we think of greenhouse gases and climate change, we think of carbon dioxide, but it is not the only greenhouse gas. All of these gases are obviously produced naturally, but human
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What is pneumonia? Pneumonia is an infection that causes the air sacs in the lungs to become inflamed and sometimes full of liquid. The word pneumonia was coined in 1603 and it comes from the Greek “pneumon”, which means lung. Pneumonia is caused when viruses, bacteria, or other microorganisms infect the lungs. It is a
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How do painkillers work? By reducing the chemical responsible for pain, by reducing the amount of the chemical responsible for pain in the brain, or by blocking the pain signals to the brain. Painkillers are called analgesics, which comes from the Greek word analgesia, meaning “without pain”. It was first used in reference to painkillers
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What is DDT? It stands for dichloro-diphenyl-trichloroethane and was the first synthetic pesticide. It was banned in 1972. DDT didn’t start being used in large quantities until after the Second World War, but it had been discovered quite a while earlier. Othmar Zeidler, an Austrian chemist, first synthesized DDT in 1874. Nobody realized that it
