Rocket rolls a toy car down a ramp into the shop. It zooms right past the finish line.
"It needs a way to stop!" he says.
Raven watches the car roll under the bench. "What do you notice? What makes a real bike stop?"
Nova hovers over the shop bike and blinks at the handlebar. "Think back to the force that fights sliding," she says.
Friction is a force between two surfaces that rub together.
Friction slows or stops moving things.
All brakes share one big idea. They add friction, usually on the wheel.
More friction on the wheel means the bike slows down.
The very first bikes had no brakes at all!
Many bikes have hand brakes. Look at the handlebar.
A brake lever sits where a hand can reach it while riding.
Brake pads are small blocks near the wheel.
On many bikes, the pads press on the rim. The rim is the metal hoop that holds the tire.
| Part | Where it is | Its job |
|---|---|---|
| brake lever | on the handlebar | the rider squeezes it |
| cable | from the lever to the brake | carries the pull |
| brake pads | next to the wheel | press on the wheel |
| rim | outside hoop of the wheel | the surface the pads rub |
| Statement | True or false? |
|---|---|
| Friction can slow a moving thing. | ? |
| Brakes take friction away from the wheel. | ? |
| A brake lever is on the handlebar. | ? |
| On many bikes, the pads press on the rim. | ? |
Great brake hunting! Tomorrow we follow the pull from your hand all the way to the wheel.