1 visual infographic a day with practical knowledge you can actually use.
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why can you usually not tickle yourself?
your brain predicts the touch you are about to make and turns down the expected sensation
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why can you see through a microwave door mesh?
its holes are tiny compared with microwave waves but huge compared with light waves. light gets through, while the mesh reflects microwaves
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why do your ears pop on a plane?
pressure changes around your eardrum. when the eustachian tube opens, it equalizes the pressure
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why do jeans have metal rivets?
they reinforce the points that pull hardest, especially pocket corners and seams
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why do we shiver when cold?
your muscles start rapid involuntary contractions. that activity produces extra heat
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why do f and j keys have bumps?
they are touch markers. your index fingers find f and j, then the rest of the home row follows
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why do we get goosebumps?
tiny muscles at each hair follicle pull the hairs upright. the skin dimples into goosebumps
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why do tires have little bars in the grooves?
they are wear bars. when the tread wears level with them, the tire has reached the U.S. replacement limit
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why do hiccups make that hic sound?
your diaphragm suddenly pulls air in. then the opening between your vocal cords snaps shut
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why are so many pencils hexagonal?
six flat sides give your fingers purchase and make the pencil much less likely to roll off the desk
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why is one nostril often clearer than the other?
your nasal passages take turns. tissues on one side swell a little while the other opens for airflow
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why is there a little plastic table in a pizza box?
it props up the lid, so it does not press into the pizza and its toppings
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why do your fingers wrinkle in water?
water makes tiny blood vessels in your fingertips constrict. the skin folds into channels that may help with wet grip
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why do qr codes have three big squares?
they are finder patterns. they tell a scanner where the code is, which way it faces, and how large it appears
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why does ice cream hurt your forehead?
cold food can chill the roof of your mouth, while the pain is felt in your forehead
that mismatch is referred pain
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why does a tape measure hook move?
it slides by its own thickness, so the zero point works from an outside edge or an inside wall
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ice floats because freezing gives water a more open structure and a lower density. that floating layer also insulates liquid water and life below.
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bar charts use length to represent value. cutting off zero can make a small difference look huge, so always check where the scale begins.
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grapefruit can change the amount of some medicines in your body, sometimes raising it and sometimes lowering it. check the label or ask a doctor or pharmacist.
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