atmosphere
the layer of gases surrounding Earth or other planets
Harmful gases from factories pollute Earth’s atmosphere every day.
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gravity
the natural force that pulls things toward each other
My science teacher said that without gravity, everything would float around!
photo credit: Zastolskiy Victor/Shutterstovk
technology
something created by science to solve problems
Air bags in cars are one example of how technology can help save lives.
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spacecraft
vehicles for space travel
A number of spacecraft have landed on Mars now, but Viking 1 was one of the first.
photo credit: JPL/NASA
orbit
a curved path around Earth
The moon is in constant orbit around Earth.
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