How to Use Simple Machines to Make an Egg Breaker

Written by jess huckins
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How to Use Simple Machines to Make an Egg Breaker
Use this simple machine to break an egg. (Hemera Technologies/ Images)

Simple machines are devices that change the direction and or magnitude of force by storing, releasing or transferring kinetic energy. There are several types of simple machines. A machine to make an egg breaker works by turning a wheel and axle to lift a weight with a pulley. When the weight is dropped onto a lever, it moves another lever into position as an inclined plane and releases an egg to roll down and impact a breeze block. Wedges and screws, which are also simple machines, are variations on an inclined plane.

Skill level:
Moderately Easy

Things you need

  • Spool
  • String
  • Staples
  • Screws
  • Small fixed pulley
  • Wood dowels
  • Tape
  • Paper cup
  • PVC Piping
  • 2 1-by-4 planks
  • Weight (4-inch square piece of 2-by-4 wood will do)
  • Eye hook
  • Breeze block
  • Scrap wood
  • Egg

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  1. 1

    Thread the dowel through the spool and attach it to a small wood cradle that can be constructed out of scrap wood. This cradle should hold the dowel off the ground and allow the spool to turn freely. Staple or affix one end of the string to the spool so that when turned with the dowel, the string will wind around it.

  2. 2

    Position the pulley and attach the weight. We need to change the horizontal motion of the wheel to vertical motion to lift the weight. Make sure the pulley you use has points for mounting or rope threading. Thread another dowel through the holes in the pulley, and tape them down between two desks or some place off the ground. You will potentially have to adjust the height later, to limit the amount of force transferred to the first lever. Now, take the weight, and screw in the eye hook to the top of it in the centre. Then, thread the string through the pulley and tie it to the weight.

  3. 3

    Build the levers. Cut the PVC piping to the width of the 1-by-4 planks; these will serve as the fulcrums for the levers. Position the fulcrums in the middle of each plank and attach them with screws. On one of the levers, staple the paper cup on its side with the open end facing toward the middle of the lever. This will serve as a basket to hold the egg. Position the levers next to each other. One end of one lever should be under the weight and the other lever (the one with the basket) should be positioned so that the left most side rests on the right side of the first lever. They should overlap so that when the weight is dropped on the first lever, it flips the second lever, and releases the egg.

  4. 4

    Position the breeze block about one to two feet away from the end of the second lever. Load the egg, make sure the levers are set in the correct position and wind the crank. When the weight is at the top of its travel, release the crank. These cooperating simple machines should cause the egg to roll off the second lever into the breeze block.

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