Submarines can move up and down underwater by changing their density. They take in water through spe
[820호]
A tsunami is a series of powerful waves caused when something suddenly moves a large amount of water
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Vitamins are your body’s helpers behind the scenes. They help everything run smoothly. Vitamin A i
[818호]
How does a place get included on the UNESCO World Heritage List? First, it must meet at least one of
[817호]
Before calculators existed, NASA engineers and astronauts used a tool called a slide rule to solve p
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Our lifestyles affect the environment. What we buy, what we eat, and how we get rid of trash can sav
[764호]
Radiation is the energy that travels through space or objects. We see it every day. It is the sunlig
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Animals get creative during abnormally hot weather. Dogs stick out their tongues and pant, replacing
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A myth is an old story told long ago to explain things people didn’t understand, like how the sun
[813호]
Stardust is the remnants of dying stars. When stars reach the end of their lives, they release gas a
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