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Science Test Study Guide - Unit 10

Unit 10 Test

February 13

Vocabulary

pulley: a wheel with a rope or chain around it

compound machine: a machine made of up of 2 or more simple machines

work: is the use of a force—a push or a pull—to move an object in the same direction as the force

simple machines: need only one force plied to make work easier to do

screw: an inclined plane that winds around a shaft

Concepts

·        a ramp that is less steep lessens the amount of force you need to apply to push a box up a ramp

·        scissors and shears are made up of levers and wedges

·        a broom uses a lever to work and is a simple machine

·        to decrease the amount of force to pull something up a ramp, you increase the length of the ramp

·        an inclined plane is also a ramp

·        it takes less force to pull something up a longer ramp

·        it takes less force to turn a screw than drive a nail into wood because the threads on the screw increase the distance it travels

·        goggles are safety equipment that should be used for an experiment

·        a flag poles uses a pulley to change the direction of force

·        a wedge it two inclined planes back to back

Writing

A screw is easiest to turn when its threads are closer together.  The further away the threads, the harder it is to turn.

Work is done only when a force moves an object.  If the object does not move then it is not work.

A science experiment should only test one variable at a time.  Students need to decide which variable they want to test and make sure everything else in the experiment is the same.

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