wunder beta⚙️ Levers, Pulleys, and Gears
How do you lift something too heavy to budge? Simple machines — levers, pulleys, and gears — let a small force do a big job.
What you’ll learn
- LeversName the parts of a lever and explain that simple machines trade force for distance.A lever is a stiff bar that turns on a pivot called the fulcrum, with the effort you apply at one end and the load at the other. Like every simple machine, a lever trades force for distance: push a long way with a small force to lift a load a short way with a big force. Seesaws, wheelbarrows, and scissors are all levers.
- PulleysExplain how pulleys change the direction of a force and how extra wheels reduce the effort needed.A pulley is a grooved wheel with a rope. A single pulley changes the direction of your force, so pulling down lifts a load up. Adding more wheels shares the load so you need less force, but you must pull much more rope. Cranes and flagpoles use pulleys to lift heavy loads.
- GearsDescribe how gears pass on turning motion and how gear size changes speed and direction.A gear is a toothed wheel that turns another gear it touches, passing on turning motion. When a big gear drives a small one, the small gear spins faster but with less turning force, and the two spin in opposite directions. Bicycles use a chain and gears to make pedalling easier or faster.
Questions this course answers
On a lever, what is the fixed point the bar turns on called?
The fulcrum is the pivot point the lever turns on, between the effort and the load.
What does a simple machine trade to help you?
A simple machine lets you use less force, but you must move it a greater distance — force is traded for distance.
What is one thing a single pulley does to your force?
A pulley changes the direction of a force, so you can pull down on the rope to lift the load up.
Adding more pulley wheels lets you lift a load with less force, but you must...
More wheels share the load so it feels lighter, but the trade means you pull a lot more rope.
When a big gear turns a smaller gear, the small gear...
The smaller gear has fewer teeth, so it must turn more times to keep up — it spins faster than the big gear.
Which of these carries your pedalling force to a bicycle's back wheel?
A chain links the pedal gears to the back-wheel gears, passing your effort along to turn the wheel.
Grounded in trusted sources
- BBC Bitesize
- Britannica Kids
- The Physics Classroom
- NASA
Every Wunder lesson is built from real, reputable sources — never invented.
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