Simple Machines

physics · tools · mechanical advantage · inventions

Levers are magical sticks. A lever is a rigid bar that rotates around a fixed point called a fulcrum. By pushing down on one end, you can lift something heavy on the other end, like using a crowbar to pry open a crate.

Wheels multiply movement. A wheel and axle lets you move things smoothly and quickly. The wheel is much bigger than the axle it spins on, so a small spin of the axle makes the wheel turn a large distance.

Pulleys redirect pulling power. A pulley is a wheel with a rope around it that helps you lift heavy objects upward. Using multiple pulleys together makes the job even easier because you spread the weight across more rope.

Ramps make slopes helpful. An inclined plane is just a ramp. It lets you move something heavy to a higher place by pushing it up the slope instead of lifting it straight up, which takes much less force.

Screws twist things tight. A screw is like an inclined plane wrapped around a pole. When you turn it, the spiral shape grips or fastens things together, which is why screws hold things so well.