2. Teacher Resources  Chapter 4 Color Teaching Transparency —Ch 4.2Ch 4.2  Laboratory Black line Masters Laboratory Black line Masters  Electronic Book Electronic Book  Skill Sheets

3. Chapter 4.2 The Lever CPO Science Integrated Physics & Chemistry

4. Developing A Model  Can you give me an example of a lever?  What is the input force and the output force?  What makes a lever?

5. Three Classes of Levers  First Class - fulcrum between Input and output  Second Class – output between fulcrum and input  Third Class – input between fulcrum and output

6. Key Questions  What is a lever?  How does a lever work?  Does a lever fit our definition of a machine from Ch. 4.1?  How can we calculate the mechanical advantage of a lever?

7. Developing An Experiment  What variables are there?  What are we going to test?  What material will we need?  What data needs to be collected? —Input & output force —Length of the arms

8. Run The Experiment  Set up the lever  Tips: —Before you start recording data try and get several different combinations to balance —Once you have your data develop a mathematical rule for the lever

9. What Did You Learn?  What are the relationships? —What did you notice about the lengths of the input & output arms of the lever and the weights? —If I need to lift a large object with a lever, do I want to be close to the fulcrum or far from it? —Is there any math rule we can use to describe this relationship? —For a lever is there more than one way to find mechanical advantage?

10. Summary  Is a lever a simple machine? —How do you know?  Can you determine the mechanical advantage of the lever? —How? Is there more then one way to calculate it?