Belt and chain: transmitting rotation
Belt and chain like on a bike: rotation keeps its direction, speed depends on wheel size. For kids 8+.
3D
Age 8+10 min
Gears & transmissionsMachines & mechanisms3D scene
Loading simulation…
Drag to orbit the scene, scroll to zoom. Press “Run”.
What the experiment shows
The small driving pulley turns the big one through a belt (chain). The direction is the same but the big one is half as fast — the ratio of the radii.
How to run it
- Run and compare the two drives: belt and chain.
- Select a transmission in the layers and change the radii R₁ and R₂ — how does the speed change?
Questions to discuss
- Why does a bike use a chain but a car’s fan use a belt?
- Which way does the driven wheel turn if the belt is twisted into a cross?
The science
The belt and chain move at the same linear speed on both wheels, so ω₁·R₁ = ω₂·R₂. A chain does not slip and transmits motion exactly; a belt is softer and quieter but may slip.
Try it at home
Put a rubber band over two round pencils of different thickness and turn one — the other turns the same way.
What to change in the editor
- Make the driven pulley smaller than the driver — it gets faster.