Pulleys help lift — Physics, 4–6 years
A wheel with a groove and a rope can help us lift something or change the direction of a pull.
Idea
A pulley is a small wheel with a groove around its edge. A rope sits in the groove, and the wheel turns as the rope moves. Pulling one end can lift a load on the other end, often from a more convenient place.
Why it matters
People needed to lift heavy things to high places, such as stones for buildings or a flag on a tall pole. A pulley lets a person pull down while the load goes up, which can be easier to do and easier to see.
Try it step by step
Tie a small toy to one end of a string and place the string over a smooth wheel or a safe pulley. Pull the free end down by 20 centimetres. The toy rises about 20 centimetres, while the pulley changes your downward pull into an upward movement.
A common mistake
A pulley does not make a heavy object disappear or become weightless. It changes how the pull is made, and some pulley arrangements share the load so less force is needed, but more rope must then be pulled.
Where we see it
A flagpole uses a pulley so a person on the ground can raise or lower the flag. Cranes use many pulleys and ropes to move building materials. Sailors, theatre workers and rescue teams also use them when a load must travel up or down safely.
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