Year 5 Science · Levers, pulleys and gears · Summary

Year 5 Science Levers, pulleys and gears: summary and key words

Part of the Year 5 Science levers, pulleys and gears chapter. Chapter overview · whole chapter on one page

Chapter summary

Skill	Method
Levers	A lever turns about a pivot. A longer effort arm makes the effort smaller, so a smaller force has a greater effect.
Pulleys	A fixed pulley only changes the direction of the pull. A movable pulley shares the load, so the effort is about half.
Gears	Meshed gears turn in opposite directions. A large gear turns more slowly than a small gear that turns it.
Choosing	Choose the mechanism that fits the job, and give a reason based on evidence from a fair test.
Fair tests	Change only one thing, such as the arm length or the pulley set-up, and keep the load the same.

I can name the pivot, the effort and the load in a lever, and explain why a longer effort arm helps
I can explain how a movable pulley makes lifting easier, and what a fixed pulley does
I can explain how a small gear turning a large gear changes speed, and find the number of turns
I can choose a mechanism for a job and give a reason, based on evidence
I can plan and report a fair test of a mechanism, with a conclusion that matches the evidence

lever: a rigid bar that turns about a pivot, so that a small force can have a greater effect
pivot: the fixed point that a lever turns about; also called the fulcrum
effort: the force you apply to a lever or a pulley
load: the force that is lifted or moved by a mechanism
effort arm: the distance from the pivot to the place where the effort is applied
pulley: a wheel with a groove, which a rope runs over to lift or move a load
movable pulley: a pulley that moves with the load, so that the load is shared between two parts of the rope
gear: a toothed wheel that fits with another gear, so that one turns the other
driver: the gear that is turned first, and turns the other gear
mechanism: a device, such as a lever, pulley or gears, that makes a force easier to use