Activity

Simple machines on a bike

Summary
After being able to recognize simple machines, find simple machines on a bike.
Science content
Physics: Motion and Forces, Newton’s Laws, Gravity (K, 2, 6)
Physics: Simple and complex Machines (5)
Lessons activity is in
Materials
  • a bike with lever brakes
Procedure

A bike is a compound machine - an assembly of several simple machines.
Find the simple machines in a bike, and whether the force in is less over greater distance or more over less distance.

Wheel and axle: The wheels, pedals, crankset, cassette
Levers: brakes, gear shifters, handlebars
Inclined planes and wedges: Screws holding it together, teeth on the chain rings. Tyre repair kit (also a lever).
Pulleys: chain on gears. Parts of the shifting mechanisms, braking mechanisms, and the drive train (chain on gears).

Determine which way the force effect works in each case, the levers being the easiest to study:
The brake levers are moved with little force over a long distance to result in a great force over a small distance (the brake pad grasping the wheel rim/disc).
The handlebars are moved with little force over a large distance to result in a greater force over a smaller distance (the pivoting of the handlebar stem).
The pedals are pushed with little force over a large distance to result in a greater force over a smaller distance (turning the crankset).

See attachment for stand-alone activity, finding levers on a bike.

Attached documents
Grades taught
Gr 4
Gr 5
Gr 6
Teaching site
Carnarvon Elementary
Tyee Elementary