What is a wheel and axle mechanism?
A wheel and axle mechanism is a simple device you make when you connect one or more wheels to an axle.
They are used to help things move.
A wheel is a round, flat object made of a hard material.
An axle is a rod that passes through the centre of the wheel.
Video: Wheel and axle mechanisms
Join Emma-Louise in the workshop to find out how wheel and axle mechanisms are made, why they are useful and where they can be found.
What do this toy car and this bicycle have in common?
They both have mechanisms that help them do what they need to do.
A mechanism is a series of moving parts, working together to do a specific job. Both the bicycle and the toy car have wheel and axle mechanisms that help them to move.
So, how does this work?
A wheel moves forward by rolling in a circle, using circular motion. Whoops!
To create a wheel and axle mechanism, we need an axle that can help control the motion of the wheel. This axle is fixed to the wheel through the middle, like this. Now, when the axle turns, the wheel turns too.
Let’s put a wheel on each end.
Now when we roll the axle, both wheels turn and we have control of the forward or backwards motion of the wheels.
If we attach this to a vehicle with an axle holder, like this toy car has, then the vehicle can use the circular motion of the wheel and axle mechanism to allow the car to move forward.
This toy car has one of these mechanisms at the front and at the back.
Wheels come in lots of different sizes.
For example, a tractor’s wheels are large and wide so they can travel across muddy ground without sinking into the mud. But a roller skate’s wheels are small so they can fit under your feet, but they are wide enough to help you balance. Wheel and axle mechanisms can be used in other ways as well, like in this windmill, this Ferris wheel and this rollercoaster.
When you’re walking around, why not try and spot as many different things that use the circular motion of a wheel and axle mechanism, as you can?
What is a wheel?
A wheel is a circular, flat object that can spin around a central point.
Most are made from hard materials, such as metal, plastic or wood.
This is so they can carry heavy loads and be used many times without breaking.
Wheels are used in vehicles, such as cars or bicycles, to help them move forward and backward.
What is an axle?
An axle is a rod that passes through the centre of a wheel.
The wheel grips the axle tightly, so the wheel and axle turn together.
Axles help wheels stay in place and spin smoothly.
Examples of wheel mechanisms
Wheels can be found everywhere.
They help cars, bicycles and trains move.
They are sometimes found hidden in things. For example:
- wheelbarrows
- rollercoasters and Ferris wheels
- sliding mechanisms of drawers
- DVD players and games consoles
- wheelchairs
Key words
| Axle | A rod that passes through the centre of a wheel, allowing it to spin. |
| Mechanism | A set of moving parts that work together to make something happen. |
| Vehicle | Any form of transport to move people or things. |
| Wheel | A circular, flat object that can spin around a central point. |
Quiz
Take this quiz to find out what you know about wheel and axle mechanisms.
BBC Bitesize newsletter. External Link
Sign up to our BBC Bitesize newsletter to receive monthly news, stories and updates on latest Bitesize content.
More on Mechanisms
Find out more by working through a topic
- count1 of 3
- count2 of 3
