A crank that lifts a duck

In the picture

1. 1Crank handle: you turn it to make the toy move
2. 2Cam: a lopsided disc that pushes as it turns
3. 3Follower lever: it rides on the cam and lifts the duck

Examples

• A music box with a little dancer that moves up and down
• A toy with a bird that bobs when you wind the handle

Quiz: A crank that lifts a duck (Age 9)

1. 1

   What does a cam do in a toy?

   • It makes the toy turn faster
   • It turns up-and-down motion into round-and-round motion
   • It turns round-and-round motion into up-and-down motion
2. 2

   Which part of a lopsided cam pushes the lever the highest?

   • The part nearer to the centre
   • The part farther from the centre
   • Every part pushes the same amount
3. 3

   What does the follower lever do?

   • It rides on the cam and lifts the duck
   • It is the lopsided disc that pushes
   • It is the part you turn by hand

The answers, each with its explanation, are in the app. This quiz is free there while the lesson is in the free week.