ELI16 category
Science
How the world, space and nature work.
Why do onions make you cry?
Cutting an onion damages its cells, causing it to release a chemical gas. When the gas reaches your eyes, it reacts with the moisture there and makes an irritating substance, so your eyes produce tears to wash it away.
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why do we yawn?
We yawn because it helps the brain and body shift between states, such as waking up, getting sleepy, or becoming more alert. Yawning may also help cool the brain slightly and stretch muscles around the face and jaw. Scientists are still not completely sure why it happens.
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tell me why the moon is controling the sea
The Moon does not control the sea like a remote control. Its gravity pulls on Earth's oceans, creating tides: regular rises and falls in sea level. As Earth rotates, different coastlines move into these raised areas of water, causing high and low tides.
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Why do cats purr?
Cats purr mainly when they feel comfortable, but they can also purr when they are stressed, in pain, or trying to calm themselves.
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Why is the sky blue?
Sunlight contains lots of colours. Blue light gets scattered around the atmosphere more than most other colours, so the sky looks blue.
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Why do we have seasons?
Earth’s tilted axis causes the seasons. As Earth travels around the Sun, different hemispheres receive more direct sunlight and longer days at different times of year.
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Why do astronauts float if gravity still exists?
Astronauts in orbit float because they and their spacecraft are falling together around Earth. Gravity is still acting on them.
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