KS3 Science · Physics
Gravity and space
Six short lessons. Look at the picture, learn three things, then play.
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Puzzles
These two are for the whole topic. Each lesson has a word search and a crossword of its own as well, at the top of its page.
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The whole topic on one page. Tap it to make it bigger.
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Key words
Mass The amount of matter in an object, measured in kilograms
Weight The force of gravity on an object, measured in newtons
Gravity A force that pulls any two objects towards each other
Gravitational field strength The force of gravity on each kilogram, in N/kg
Orbit The path of a planet, moon or satellite around a larger body
Natural satellite A moon: a body, not made by people, that orbits a planet
Artificial satellite A machine that people have put into orbit
Star A huge ball of hot gas that gives out its own light
Planet A large ball of rock or gas that orbits a star
Solar system The Sun and everything that orbits it
Galaxy A huge collection of stars, gas and dust, held together by gravity
Milky Way The galaxy that our solar system is in
Universe Everything that exists, including all the galaxies
Exoplanet A planet that orbits a star outside our solar system
Axis The imaginary line through the poles that the Earth spins around
Day The time the Earth takes to spin once on its axis
Year The time the Earth takes to orbit the Sun once
Light year The distance that light travels in one year