Levers Poster Elements

Image Credits and Permissions

  • Falling Elf is manufactured from Microsoft clipart that is in the public domain
  • Photo of egg slicer by Rainer Zenz available on used with permission.
  • Photo of trapdoor by English Lock available on used with permission.
  • Photo of post hole digger by Tenbergen available on used with permission.
  • Photo of fireplace bellows by Jongleur100 available on released to public domain.
  • Photographic reproduction of Archimedes lever, originally an engraving fromMechanics Magazinepublished in London in 1824, available from now in the public domain.
  • Photo of obelisk in Cairo by Neithsabes, available at released to public domain.
  • Drawing of catapult from Enciclopedia Romana 1962, available from used with permission.
  • Remaining photos from Microsoft, released to the public domain.

The Evil Elf Fell !!

To remember the lever classes, write it this way:
The EFL ELF FEL

EFL
1st class

ELF
2nd class

FEL
3rd class
Don’t Be Fooled!
These pictures show the same lever, just from two different sides.

Which class is this lever?
Levers Can Be Oriented in Different Ways





All three of these levers are the same class. Which class?
Where is the Load?
Some levers don’t move a physical load, just the lever itself. Their main purpose is to overcome resistance.








How is the direction of the load related to the direction of the resistance?
/ Investigating Levers /
  • Find the Fulcrum– that’s the hinge, the turning point, the axle, the pivot point of the motion
  • Find the Effort– that’s the push, the pull, the lift, the applied force of the motion
  • Find the Load– that’s the thing you want to move or the resistance you want to overcome

What is a Lever?
  • A lever is a beam attached to fulcrum that allows us to exert efforton the beam to move a load.
  • It is a simple machine that makes it easier to do some work.
  • Many of the tools we use are levers.
  • There are three classes of levers.

1st Class Levers

In a 1st class lever, the fulcrum is between the effort and the load.

2nd Class Levers

In a 2nd class lever, the effort is on one end and the fulcrum is on the other end. The load is in the middle.

3rdClass Levers

In a 3rdclass lever, the fulcrum is on one end and the load is on the other end. The effort is in the middle.

Simple Lever or Compound Lever?
A simple lever has one beam that pivots on the fulcrum.
A compound lever has two levers that work together.

Can you find levers around your house? Which ones are simple levers? Which ones are compound levers? What is the class of each simple lever that you find?
Extra Challenge: What is the class of each simple lever that makes up a compound lever?
A Bit of History

Give me a place to stand, and I shall move the Earth.
~Archimedes
The earliest writings about levers that still exist date from the 3rd century BC, when Archimedes discovered how the effort and load forces related to their distances from the fulcrum.
More History

Historians believe that in ancient Egypt, levers were used to move and uplift obelisks weighing more than 100 tons. Modern engineers have even done experiments to prove how ancient methods could have accomplished these feats.