Transcript Simple Machines - Florida Science Olympiad Home Page
Simple Machines
Mike McKee University of Central Florida Orlando, Florida October 7, 2006 1
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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□ Lever
Four Types of Machines
□ Inclined Plane □ Pulley □ Wheel and Axle 3
Select a station
In 15 minutes: □ Determine the IMA □ Determine the AMA □ Determine the Efficiency □ Record your procedures □ Report back to the group 4
Ideal Mechanical Advantage
PULLEYS: IMA = Distance you move Displacement of the object Problems with this?
Units?
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Actual Mechanical Advantage PULLEY’S: AMA = Force (weight) of object Force you measure Units?
Problems?
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Efficiency
□ AKA energy loss from friction!
□ Why do we care?
Efficiency = AMA x 100% IMA 7
Pulleys
Why the difference?
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Pulleys
□ Why not 20 Newtons?
Inclined Plane
□ Why is the height called the resistance distance?
http://www.walter-fendt.de/ph14e/lever.htm
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Inclined Plane
IMA = Length of Ramp Vertical Height of Ramp How can you improve IMA?
http://www.walter-fendt.de/ph14e/inclplane.htm
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Levers
Three types. How are they Different? Which is best? Examples of their use?
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Levers
IMA = Length of Effort Arm Length of Resistance Arm 13
Wheel and Axle
□ What do you change to improve mechanical advantage? □ How did you measure distance moved and displacement?
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IMA = Radius of Effort circle Radius of Resistance circle 15
Measuring AMA
AMA = Force of weight or object Force you apply 16
Actual Mechanical Advantage Measure force with spring scale where you pull!
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Actual Mechanical Advantage □ What’s wrong with this picture?
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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.
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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.
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Contact
Mike McKee University of Central Florida [email protected]
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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