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Simple Machines

Simple Machines. Mike McKee University of Central Florida Orlando, Florida October 7, 2006. Simple Machines. What is the purpose of a simple machine? What should you be measuring as evidence of this purpose? How will this guide your calculations and help you determine what to measure?.

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Simple Machines

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  1. Simple Machines Mike McKee University of Central Florida Orlando, Florida October 7, 2006

  2. Simple Machines • What is the purpose of a simple machine? • What should you be measuring as evidence of this purpose? • How will this guide your calculations and help you determine what to measure?

  3. Four Types of Machines • Inclined Plane • Wheel and Axle • Lever • Pulley

  4. Select a station In 15 minutes: • Determine the IMA • Determine the AMA • Determine the Efficiency • Record your procedures • Report back to the group

  5. Ideal Mechanical Advantage PULLEYS: IMA = Distance you move Displacement of the object Problems with this? Units?

  6. Actual Mechanical Advantage PULLEY’S: AMA = Force (weight) of object Force you measure Units? Problems?

  7. Efficiency • AKA energy loss from friction! • Why do we care? Efficiency = AMA x 100% IMA

  8. Pulleys Why the difference?

  9. Pulleys • Why not 20 Newtons? http://www.walter-fendt.de/ph14e/pulleysystem.htm

  10. Inclined Plane • Why is the height called the resistance distance? http://www.walter-fendt.de/ph14e/lever.htm

  11. Inclined Plane IMA = Length of Ramp Vertical Height of Ramp How can you improve IMA? http://www.walter-fendt.de/ph14e/inclplane.htm

  12. Levers Three types. How are they Different? Which is best? Examples of their use?

  13. Levers IMA = Length of Effort Arm Length of Resistance Arm

  14. Wheel and Axle • What do you change to improve mechanical advantage? • How did you measure distance moved and displacement?

  15. IMA = Radius of Effort circle Radius of Resistance circle

  16. Measuring AMA AMA = Force of weight or object Force you apply

  17. Actual Mechanical Advantage Measure force with spring scale where you pull!

  18. Actual Mechanical Advantage • What’s wrong with this picture?

  19. ABC - CBV As you prepare, have students construct their own meaning. Have students do the Activity Before Concept, then Introduce the Concept, then follow up with Vocabulary. Always spend as much or more time discussing the results and concepts than they did performing the experiment! This is the heart of Inquiry, which we did today.

  20. Whiteboarding Whiteboards can be purchased from Home Depot or Lowes. Have them cut into 6 pieces and use with groups. To promote discussion, have a mall walk, in which students walk around to other whiteboards and then ask questions of the groups. Cut pieces into 1 x 1 for individualized formative assessment.

  21. Contact Mike McKee University of Central Florida mmckee@creol.ucf.edu Weather Lessons and Videos: www.wesh.com - Click on Hank and Hannah www.weatherplus.com – University Archives Other professional development: www.inquiryinstitute.org ; www.floridascienceolympiad.org

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