Simple Machines for Kids
See how levers, ramps, pulleys, and wheels make work easier. Move sliders to change each machine and watch the effort change. Then test yourself in Challenge mode! All computation runs in your browser.
Mode
Pick a machine
Lever (Seesaw)
Load Arm
1.00 m
Effort Arm
1.00 m
Mech. Advantage
1.00
Effort Needed
100.0 N
Reference Guide
Levers
A lever is a bar that pivots on a point called the fulcrum. When you push down on one end, the other end goes up.
Move the fulcrum closer to the load and you need less effort to lift it. The trade-off is you move your end a larger distance.
Mechanical Advantage = effort arm ÷ load arm.
Examples: seesaw, crowbar, scissors, wheelbarrow.
Ramps (Inclined Planes)
A ramp is a flat surface tilted at an angle. It trades distance for effort. A shallower ramp is easier to push up, but longer.
A steeper ramp is shorter but harder to push up, almost like lifting straight up.
Mechanical Advantage = ramp length ÷ height.
Examples: playground slide, wheelchair ramp, loading dock.
Pulleys
A pulley is a wheel with a rope around it. A single fixed pulley changes the direction of your pull (pull down to lift up) but does not reduce effort.
A compound pulley (fixed + movable) cuts the effort in half. You pull twice as much rope, but with half the force.
Mechanical Advantage = number of supporting rope segments.
Examples: flagpole, crane, blinds, well bucket.
Wheel and Axle
A wheel and axle is a large wheel attached to a smaller rod (the axle). When you turn the big wheel, the axle turns with more force.
The bigger the wheel compared to the axle, the greater the force multiplication.
Mechanical Advantage = wheel radius ÷ axle radius.
Examples: doorknob, steering wheel, screwdriver, bicycle gears.