Why Does Bread Rise?
Bread rises because yeast eats sugar and releases carbon dioxide, and dough is elastic enough to hold the gas in bubbles. Baking is what turns those bubbles into a fixed structure.
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How Photosynthesis Works
Plants build themselves out of air. Photosynthesis uses light energy to split water and attach the hydrogen to carbon dioxide, producing sugar and releasing oxygen as the leftovers.
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Why Do We Get Sunburned?
Sunburn is not the sun heating your skin. It is ultraviolet light damaging DNA in skin cells, and the redness and pain are the body’s repair and cleanup response starting a few hours later.
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What Causes the Seasons?
Seasons are not caused by how far Earth is from the sun. They are caused by a 23.4 degree tilt that changes both how directly sunlight arrives and how long it stays.
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Why Coffee Keeps You Awake
Caffeine does not give you energy. It blocks the receptor that tells your brain how tired you are, so the tiredness is still there, you just stop receiving the signal.
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Astronomers Watch a Massive Binary Star Being Assembled
Eight years of radio observations have captured a pair of massive young stars mid-formation, on a lopsided orbit with discs pointing in different directions. That rules out the simplest explanation.
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AI Weather Models Move to Hour-by-Hour Forecasts
A new generation of machine learning weather models produces hourly global forecasts at five kilometre resolution, and is being wired directly into consumer products.
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How Soap Actually Cleans
Soap molecules have a water-loving head and a grease-loving tail. That split personality lets them grab oil with one end and let water carry it away with the other.
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How Vaccines Work
A vaccine shows your immune system what a pathogen looks like without letting it cause the disease, so that meeting the real thing later is a recognition task instead of a fight from scratch.
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Why Is the Sky Blue?
Sunlight is white, air is transparent, and yet the sky is blue. The answer is a scattering effect that treats short wavelengths far more roughly than long ones.