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Science project idea on how the lever is used in doing work.
Lever Science Project Idea 
How the lever is used in doing work. Let us suppose that a heavy rock must be lifted, and we find that we are unable to do it by hand. By the use of a strong beam or a crowbar (a strong steel bar) in the way indicated in the diagram, the lifting is accomplished with little difficulty. 
The bar constitutes a lever; the point on which it rests is the fulcrum, and the portions of the bar on either side of the fulcrum are the arms. The amount of force that must be applied may be determined by the following experiment .
Lever Science Experiment Use a yard or meter stick as the lever; use a 10- pound weight, placing the lever on the fulcrum in such a way that one arm is ten times as long as the other. Place small weights on the end of the long arm until the lever balances on the fulcrum and the weight is lifted from the table. What weights have you placed on the long arm? Vary the experiment by putting the fulcrum at different places, thus changing the relative length of the arms . It will be noted that the force needed to lift the weight is inversely proportional to the length of the arms. Therefore (Effort) x (its arm) = (weight or resistance) x (its arm). The slight variations from this are due to the weight of the lever, and the small amount of friction between the lever and fulcrum. Measure the distance through which each arm moves. What are your conclusions? Compare the amount of work done at the end of each arm. This experiment is duplicated in the action of the seesaw which most of you have tried. What is the position of a heavy boy and that of a light boy? Compare the distances through which each moves. Give all the uses you can of levers of this kind. These are called levers of the first class. 
2. Considering the wheelbarrow as a lever, where is the fulcrum, the resistance or weight, and the effort or power? Why is it easier to lift a bag of flour in a wheelbarrow than directly by hand? Would making the handles longer cause it to be harder or easier to lift the load? Why are the handles not made longer? Give other examples of levers with the same relative arrangement of fulcrum, resistance or weight, and the effort or power. In these levers compare the length of the power arm and the entire lever. These are called levers of the second class. 
3. Considering a pitchfork or a fishing pole as a lever, where is the fulcrum, the resistance or weight, and effort or power? What is the advantage in using such a lever? In using a pole 10 feet long, about how much force must be used to land a fish weighing 5 pounds? What are the advantages and disadvantages of using a very long handled pitchfork? Give other examples of levers of this kind. They are called levers of the third class. 4. Explain how the bones of the human body act as levers during walking, running, lifting, and throwing. To which class of levers do they belong?  
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