Discover - Identifying and Building

It's okay to have fun on a lever!  One of the most favourite childhood playground toys is the teeter-totter.  This type of lever does not provide any speed or force advantage because the fulcrum is right in the middle.  The point of this lever is not to move something faster or move something that is heavy.  It only moves up and down.

Sometimes a single lever is not enough for the job.  Many times, inventors combine two or more levers into one tool so that it does a job better.  When two or more lever arms are combined, it is called a complex lever.
Pliers are a class 1 complex lever because two lever arms are attached together.  The pivot point is the fulcrum for both lever arms.  Most pliers, such as this one, provide a force advantage because the fulcrum is closer to the load.  You can squeeze things very hard with pliers!

Test Yourself!

Before you move on to the activity, test yourself by viewing all the levers in the Lever Identification Chart.  For each lever, answer the questions: "Simple or Complex Lever?", "Force or Speed Advantage?", and "Class 1, 2, or 3?"  When you have your answers, click the questions and read the solutions carefully to see if you were correct.

Barbeque Tongs



This is a complex lever. The fulcrum joins the two lever arms, and the ends of the lever arms work together to grab barbeque food.
This is a speed advantage. A small movement of the hands produces a large movement at the end of the tongs.
Class 3 - The effort force is in the middle.

Nutcracker



This is a complex lever. The fulcrum joins the two lever arms, and the lever arms work together to crush nuts.
This is a force advantage. A large movement of the hands produces a small, powerful movement in the teeth of the nutcracker near the fulcrum.
Class 2 - The load is in the middle.

Water Hand Pump



This is a simple lever consisting of only a single lever arm.
This is a force advantage. A large movement of the hand on one end of the lever produces a small and powerful movement on the other end.
Class 1 - The fulcrum is in the middle.

Pry Bar



This is a simple lever. There is only a single lever arm to this pry bar. (This type of pry bar is sometimes called a crowbar.)
This is a force advantage. A large movement of the hand on one end of the lever produces a small and powerful movement on the other end.
Class 1 - The fulcrum is in the middle.

Teeter-totter



This is a simple lever. There is only a single lever arm that tilts back and forth.
Neither. There is no speed or force advantage if the users sit where they are supposed to because the fulcrum is in the middle, spaced equally between the load and effort force.
Class 1 - The fulcrum is in the middle.

Golf Club



This is a simple lever. There is only a single lever arm that the golfer swings.
This is a speed advantage. A small movement of the hands produces a long and fast movement at the other end of the golf club.
Class 3 - The effort force is in the middle.

Tennis Raquet



This is a simple lever. There is only a single lever arm that the tennis player swings.
This is a speed advantage. A small movement of the hands produces a long and fast movement at the other end of the tennis racquet.
Class 3 - The effort force is in the middle.

Hammering Nails



This is a simple lever. The hammer is a single lever arm that that the person swings.
This is a speed advantage. A small movement of the hand produces a fast movement of the hammer head.
Class 3 - The effort force is in the middle.

Tooth Extractor



This is a complex lever. The fulcrum joins the two lever arms, and when the dentist squeezes the two lever arms, the extractor jaws have a very tight grip on the tooth.
This is a force advantage. A large movement of the fingers of the dentist's hand produces a small, powerful movement on the other end of the extractor that squeezes the tooth.
Class 1 - The fulcrum is in the middle.

Garden Rake



This is a simple lever. The rake is a single lever arm that the person moves into and over the ground.
This is a speed advantage. Small movements of the hands make the head of the rake move a big distance.
Class 3 - The effort force is in the middle.

Bottle Opener



This is a simple lever. The bottle opener has only a single lever arm.
This is a force advantage. A large movement by the hand on the effort force end of the opener produces small, powerful movement on the bottle cap end of the lever.
Class 2 - The load is in the middle.

Puring Shears



This is a complex lever. The fulcrum joins the two lever arms; when the gardener squeezes the lever arms both lever arms pivot on a single fulcrum.
This is a force advantage. A large movement of the fingers on the gardener's hand produces a small, powerful force on the other end that can cut through a branch.
Class 1 - The fulcrum is in the middle.
If you use scissors to build your lever, be very careful not to cut yourself.
Never hold the pointy end of scissors toward yourself.

 Notebook: How can I build the lever I need to complete the task?

  1. Click here to download this activity.
  2. Complete the activity and save it to your Machines Notebook.