First class levers, such as the seesaw, have the fulcrum located between the effort and the load.

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Robert Townsend
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A lever is a board, bar, or rod that is also referred to as the arm. The arm turns or pivots against a point or fulcrum. The object that is moved by a lever is called the load.

1 A lever is a board, bar, or rod that is also referred to as the arm. The arm turns or pivots against a point or fulcrum. The object that is moved by a lever is called the load. First class levers, such as the seesaw, have the fulcrum located between the effort and the load. Second class levers, including wheelbarrows, have the load located between the effort and the fulcrum. Third class levers have the effort located between the load and the fulcrum. With a slingshot, the hand holding the slingshot is the fulcrum, your finger is the effort, and the load is whatever you re slinging abcteach.com

2 SIMPLE MACHINES: THE LEVER List some examples of levers: Find or draw a picture of a lever and label it with the following: lever, effort, load, and fulcrum abcteach.com

3 EXPERIMENT: LEVERS Question How does the position of the fulcrum affect the amount of effort needed to move a load? Hypothesis What do you think will happen? I think that Materials a 12 inch/30 cm ruler (lever) small box of staples or other object to serve as the fulcrum eraser (load) Procedure Step 1 Place the middle of the ruler on the fulcrum so it balances. Place the eraser, or load, on one end of the ruler (e.g., at the one inch or one to two centimeter mark). Press down on the other end ruler to move the load upwards. Repeat this procedure two more times while thinking about how much effort is required to lift the load. Step 2 Next, move the staples box or other fulcrum closer to the eraser, or load (e.g., at approximately the three inch or eight centimeter mark). Press down on the other end of the ruler two or three times. Determine if it requires more or less effort to lift the object than in Step 1. Repeat Step 1 and Step 2 to compare the effort. Step 3 Move the fulcrum to the other end of the ruler (at approximately the 10 inch or 24 centimeter mark). Again, press down on the ruler two or three times while thinking about how much effort is required to lift the load. Repeat steps 1, 2, and 3 to compare the effort. Think about which step requires the least and the most amount of effort to lift the object abcteach.com

4 Results Draw a diagram of Step 1, Step 2, and Step 3. For each diagram, label the lever, effort, load, and fulcrum. Fill in the sentence blank in each box with one of the following words: least, most, or average. Step 1 This step required the amount of effort to lift the load. Step 2 This step required the amount of effort to lift the load. Step 3 This step required the amount of effort to lift the load. Conclusion It takes more effort to move a load when the fulcrum is closer to or further from (circle one) from the load. It is easier to move an object when the fulcrum is closer to or further from (circle one) to the load abcteach.com

5 WORKSHEET: TYPES OF LEVERS Find pictures of first, second, and third class levers. Paste each picture in its proper box and label with lever, effort, load, and fulcrum. First Class Lever First class levers have the fulcrum located between the and the. Second Class Lever Second class levers have the load located between the and the. Third Class Lever Third class levers have the effort located between the and the abcteach.com

WORKSHEET: CLASSIFYING LEVERS Look carefully at the

Label each object as a first, second, or third class

First Class Levers: Fulcrum is between the load and

Second Class Levers: Load is between the fulcrum and

6 WORKSHEET: CLASSIFYING LEVERS Look carefully at the pictures of the following levers. Label each object as a first, second, or third class lever. First Class Levers: Fulcrum is between the load and the effort. Second Class Levers: Load is between the fulcrum and the effort. Third Class Levers: Effort is between the fulcrum and the load. nutcracker fishing pole hammer scissors crowbar bottle opener abcteach.com

7 Answers to LEVERS Page 2: List some other examples of a lever: baseball bat fishing pole rake stapler bottle opener fork scissors seesaw/teeter-totter broom hammer screwdriver tennis racket crowbar hockey stick spatula tongs hoe tweezers nail clippers wheelbarrow nutcracker pliers Pages 3-4: Levers Experiment Results Step 1 This step required the average amount of effort to lift the load. Step 2 This step required the least amount of effort to lift the load. Step 3 This step required the most amount of effort to lift the load. Conclusion It takes more effort to move a load when the fulcrum is further from the load. It is easier to move an object when the fulcrum is closer to the load. Page 5: Types of Levers First class levers have the fulcrum located between the effort and the load. Second class levers have the load located between the effort and the fulcrum. Third class levers have the effort located between the load and the fulcrum. Page 6: Classifying Levers nutcracker 2 nd fishing pole 3 rd hammer 3 rd scissors 1 st crowbar 1 st bottle opener 2 nd abcteach.com

1103 Per 9: Simple Machines-Levers

Name Section 1103 Per 9: Simple Machines-Levers 9.1 How do Levers Work? 1) Fulcrums and forces a) Place a meter stick on the plastic tube with the 50 cm mark directly above the tube. Place a 5 newton weight