Wheel

simple machines · invention · transportation

Perfect for rolling. Wheels are round objects that turn on a rod called an axle. The round shape means they can spin smoothly without bumping or jumping, which is why they work so well for moving things.

Moving heavy stuff. When you put wheels on a cart or wagon, suddenly you can push something really heavy with just a little bit of effort. Instead of dragging something, which creates lots of friction, wheels let you roll it easily down the ground.

Simple but powerful. The wheel and axle is one of the six simple machines that help humans do work. It's simple because it has just two parts, but it's powerful because it makes difficult jobs way easier.

Different kinds of wheels. Wheels aren't just for cars and bikes. Ship wheels help steer boats, pottery wheels spin clay into bowls and pots, and special wheels called flywheels store energy in machines.