What are blisters and calluses? A blister is a pocket of body fluid that has formed between the outer layers of skin in response to damage. A callus is an area of thickened skin that has been formed to protect the skin from damage. The word “blister” came into English from the old French “blestre”, […]
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How does a gravitational slingshot work? A gravitational slingshot works by using the gravity of a planet to get an increase in speed without expending extra energy, and to change direction without losing speed. A gravitational slingshot is technically called a gravity assist because the gravity of the large body is assisting the spaceship. As
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Why are your fingers stiff when you are cold? Fingers are stiff when you are cold because the body moves the blood to more important organs, because muscles stiffen in the cold, because the joints become viscous, and because the cold can reduce nerve impulses. When our hands are exposed to the cold for a
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Why do onions have so many layers? Onions have so many layers because each layer is a modified leaf that has grown from the center out. When they are first planted, onions grow from a seed. These seeds are produced by flowers at the top of the onion’s stalk. If you think about an onion
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How does a Polaroid camera work? A Polaroid camera technically works in the same way as a regular camera, except that all of the chemicals needed to develop the photograph are already inside the photographic film that is inside the camera. These days, we mostly use digital cameras or our phones. However, back in the
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Why do we blush? We blush in response to emotions such as embarrassment, stress, and shame. Why we blush is a much more difficult question than how we blush, so let’s look at that first. How we blush is fairly straightforward. The red color of a blush is brought about by the dilation of blood
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Is a quintuple jump in figure skating possible? Technically, a quintuple jump in figure skating would be possible. It all comes down to the speed of the jump and the conservation of angular momentum. The quadruple jump is where figure skaters take off from the ice, do four complete rotations, and then land back on
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Why do fingers go wrinkly in the bath? Our fingers and toes go wrinkly when we are in the bath because of a nervous system response, not because the skin absorbs water from the bath. If you are in a bath, your fingers and your toes will very quickly become extremely wrinkly. The length of
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Why do birds sing at dawn? Birds seem to sing at dawn to mark their territory and to attract mates. Birds also sing at dusk, but the majority of singing is at dawn. This is called the “Dawn Chorus” and it is more common in the spring, breeding season, than at other times of the
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Why does gelatin set? Gelatin sets because the protein strands in it go soft when they are heated and then form into a tangled mass when they cool. Gelatin is an ingredient we use for cooking and it is taken from the collagen found in animal parts. You can get vegan gelatin, but unless it
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