Lesson One: What is a Lever?
The lever is one of the most basic forms of a machine. Levers help us lift loads with less effort. It is made up of a stiff arm, or arms that pivot, or turn. The point at which the lever turns is called a fulcrum.
Load : The object you’re lifting.
Fulcrum : Point at which the lever pivots.
Effort : The force applied to make the object move.
The images below detail each of these. Take a look.
Load : The object you’re lifting.
Fulcrum : Point at which the lever pivots.
Effort : The force applied to make the object move.
The images below detail each of these. Take a look.
Levers can be used in many different ways. A nail puller (back of a hammer) is a type of lever used to remove nails form wood. It is used in the same way a tire iron is used to pry a tire from the rim of a wheel. A lever can also be a bottle opener. The point at which the opener grabs the edge of the soda cap acts as the fulcrum, while the long end of the opener acts as the arm. The effort comes from your hand pushing down on the bottle opener to remove the cap.
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A lever helps you exert a bigger force when you turn it. When you sit on a see-saw, you've probably figured out that you need to sit further from the balance point or fulcrum, if the person at the opposite end is heavier than you. The further away from the fulcrum you sit, the more you can multiply the force of your weight. If you sit farther away from the fulcrum, you can even lift a much heavier person sitting at the other end, as long as the other person sits very close to the fulcrum on the other side. The force you apply with your weight is called the effort. Thanks to the fulcrum, it produces a bigger force to lift the load (the weight of the other person).
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Take a look at the two videos below. Both use a seesaw example when explaining how a lever works, but with a little bit of a different approach. Which do you find more helpful?
Try using a lever for yourself! In this virtual game, move the cocoons, birds, and fill the bird feeder with seed to balance the seesaw by moving the “load” and “effort”.
Try using a lever for yourself! In this virtual game, move the cocoons, birds, and fill the bird feeder with seed to balance the seesaw by moving the “load” and “effort”.
Let’s look at some other examples of levers that you might see in your everyday life:
*Activity Time!*
Now it’s time to try out some of what you learned. You are going to make a catapult using things found at home to send a Ping-Pong ball soaring through the air! (You have been provided with these materials in class already, so you should have them on hand at home!) First, you will watch this video demonstrating what you each will do. You may watch it as many times as you like to help you during this activity.
(You may ask adults or siblings for assistance or supervision during this activity if needed.)
Now it’s your turn! Use the link/links below to obtain a copy of the “Pop Fly Challenge” that will provide you with a list of instructions and information inside the engineering of levers! Each is a link to an online PDF file. One link provides the activity in English, the other in Spanish. Follow the instructions provided and begin creating!