Introduction to Levers
To learn about levers, watch the video below. Pay attention to the different parts of a lever. How many parts do levers have? What are they?
What is a lever?
A lever is a simple machine that helps lift and move objects. A lever consists of a rigid bar that rests and pivots on a support.
Parts of a Lever
Levers have three specific parts: the effort, the fulcrum, and the load. The effort is the work you apply to move the bar. The fulcrum is the support that the bar rests on. This is also known as the lever's turning point, because the bar moves about it. The load is the object that you are trying to lift or move.
Types of Levers
There are three different types of levers: class 1 levers, class 2 levers, and class 3 levers.
Class 1 Levers
In class 1 levers, the fulcrum is between the effort and the load. Effort is applied on one end to move a load on the other end.
In this type of lever, the direction of force changes. When effort is applied downward, the load moves upward. When effort is applied upward, the load moves downward.
By changing where the fulcrum is, you can change the amount of effort needed to move the load. The closer the load is to the fulcrum, the less effort it requires.
Class 2 Levers
In class 2 levers, the load is between the fulcrum and the effort. Effort is applied on one end to move a load in the middle.
In this type of lever, the direction of force stays the same. When effort is applied upward, the load moves upward. If effort is applied downward, the load moves downward.
Class 2 levers always reduce effort. By changing where the load is, you can reduce the amount of effort even more. The closer the load is to the fulcrum, the less effort it requires.
Class 3 Levers
In class 3 levers, the effort is between the load and the fulcrum. Effort is applied in between the two to move a load on the end.
In this type of lever, the direction of force stays the same. Therefore, the effort and the load move in the same direction.
Class 3 levers help us gain distance. Applying effort for even a short distance causes a load to move a longer distance.
How are levers used?
Levers help us lift and move things. They can also help us squash, grip, turn, dig, and cut things. We do these actions quite often, so as you can imagine, there are a lot of levers around us.
Where are levers found?
Levers can be found outside. A see-saw, for example, is a class 1 lever. The middle of the see-saw is attached to the ground, and acts as the fulcrum. When the effort, a person on one end, applies a force to push towards the ground, the load, the person on the other end, lifts up in the air.
Levers can also be found inside the home. A nutcracker, for examples, is a class 2 lever. The nut is the load, and is in between the effort and the fulcrum. When the effort, your hand, applies a force on the handles, the other end of the nutcracker pivots to crack the nut.
A broom is an example of a class 3 lever, and can also be found inside the home. Effort is applied by your hands when you hold the handle. As effort is applied, the top of the broom handle pivots to move the load at the bottom of the broom.