How does LiDAR help archaeologists? It can map the ground down to the millimeter, allowing archaeologists to find the remains of cities and graves that might otherwise remain hidden. LiDAR stands for Light Detection and Ranging. It is similar to sonar and radar, but it uses light instead of sound waves and radio waves. Sonar, […]
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Why are sunsets such beautiful colors? The beautiful colors of sunrises and sunsets are caused because light rays are scattered by particles in the sky. Light has different wavelengths and our eyes have evolved to detect these wavelengths, which is how we can see colors. Our eyes have a light-sensitive area which is sensitive to
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How do metal detectors work? Metal detectors work by transmitting an electromagnetic field that energizes any metal near it. There are three different types of metal detector and they all work in slightly different ways. These different types are very low frequency (VLF) detectors, pulse induction (PI) detectors, and beat-frequency oscillator (BFO) detectors. VLF detectors
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What is the smallest thing an electron microscope can see? An electron microscope can see atoms that are 0.05 nanometers long. 0.05 nanometers is a very difficult number to imagine. How small is it? Well, a human hair is about 50,000 nanometers across. There are different types of microscopes. The basic type that students use
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How does body armor work? By breaking up the bullet and removing its kinetic energy. Armor has been around for a long time, but it has always had to adapt to the technology of weapons. In the Bronze Age, they had bronze armor because it was enough to stop a bronze sword blade. Then the
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How do LED lights produce different colors? By using different materials that produce light at different wavelengths. LED stands for Light Emitting Diode and they are very different to regular light bulbs. A lightbulb produces light by passing an electric current through a very thin metal filament. This filament has to have a very high
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Why is glass transparent? Glass is transparent because light photons don’t have enough energy to excite the molecules in the glass. There are two things we need to look at here. What is glass and what is light? Glass is a non-crystalline amorphous solid. There’s a bit to unpack there. Non-crystalline refers to the structure
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What is a Scramjet? It is an air breathing jet engine that works at supersonic speeds. Right. There are three questions we need to unpack here. How does a jet engine work? How does a ramjet engine work? How does a scramjet engine work? A jet engine has fan turbines at the front of it
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How can paints be different colors? To make different colored paints, you need to add different materials for color pigments because different particles reflect different wavelengths of light. Our eyes pick up reflected light using photoreceptors that are sensitive to different wavelengths. These then travel to our brain, which associates them with a color. For
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How does a smoke detector work? There are two different types of smoke detectors, and they respond to different types of fires. There are photoelectric smoke detectors that respond to smoke from smoldering fires and there are ionization smoke detectors that respond to smoke from flaming fires. Photoelectric smoke detectors have a chamber that has
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