Wheel and axle


•      This is a simple machine.

•      It consists of a wheel rigidly attached to a rod (called axle). When one rotates the wheel, the axle also rotates.

Figure 64: A train has wheel and axle attached to it

•      Wheels help people do work in two ways.

•      If we turn a large wheel fixed to an axle, the axle will also turn.

•      We can turn something heavy, by spinning a large wheel attached to an axle that is attached to the heavy thing. That's how a pencil sharpener works.

•      We can use a lot of force to turn the axle, and that will spin the wheels really fast. For example: cars



•      The crank is used to raise a bucket of water from a well.

Figure 65: Crank

Figure 66: Ice cream maker, rotary dial telephone, phonograph

Figure 67: Skates, Doorknob

Figure 68: Stern wheeler of riverboat, navigation spinning wheels, barbecue

Figure 69: Windmill, bicycle

Figure 70: Animal cart, scooter

Figure 71: Steering wheel of ship, a wagon