Why is the Dead Sea so salty? Because the sea evaporates very quickly and there is only one source of freshwater coming in. The Dead Sea is not actually a sea. A sea is defined as “a body of water that is partly surrounded by land”. There are about fifty seas in the world, but […]
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How do scales work? There are four different types of scales and they work in different ways. They are balances, steelyard balances, spring scales, and digital scales. Balance scales are the easiest to explain and they were the first scales used to measure the weights of objects. The first balance scales were used in the
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How does the heating element in a toaster work? It is made of a metal that has a high electrical resistance so it heats up very quickly. The heating element in a toaster is made of nichrome. Nichrome is an alloy made from (usually) 80% nickel and 20% chromium. Hence its name: nickel+ chrom(e)ium. There are four
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What is the tallest a mountain can be? It depends on the strength of the surface gravity, the amount of volcanic activity, the movement of tectonic plates, and the weather. The highest mountain on Earth is Mount Everest at 8,848 meters high. Technically Mauna Kea in Hawaii is the tallest mountain if you measure from
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How long does a 747’s runway need to be? A Boeing 747 airplane needs a runway that is at least 2,300 m long to land and over 3000 m to take off. However, this is a difficult question because there are many variables that come into play when determining the necessary length of runway for
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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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