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Engage What can you do to lift your teacher?. Machines. Based upon what you already know … A machine is …. Machines … . Explain. Increase the amount of force applied to an object Increase the distance and speed an object moves Transfer force from one place to another
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Engage What can you do to lift your teacher? Machines Based upon what you already know … A machine is …
Machines … Explain • Increase the amount of force applied to an object • Increase the distance and speed an object moves • Transfer force from one place to another • Change the direction of the force
Level the Lever Explore Level the Lever -- Set-up -- Guided instruction -- Guided inquiry -- What makes this a “machine?” -- Is this a first class, second class, or third class lever? Why?
Levers Explain • First Class Resistance Fulcrum Effort • Examples: • Second Class Fulcrum Resistance Effort • Examples: • Third Class Fulcrum Effort Resistance • Examples:
Six Simple Machines • Lever Family Lever Wheel and axle Pulley • Inclined Plane Family Inclined plane Wedge Screw
A Foe for the Families? Type of Friction Demo Examples Words Starting friction Sliding friction Rolling friction
Compound machines are … Extend Rube Goldberg Machines … Rube Goldberg gets his think-tank working and evolves the simplified pencil-sharpener. Open window (A) and fly kite (B). String (C) lifts small door (D) allowing moths (E) to escape and eat red flannel shirt (F). As weight of shirt becomes less, shoe (G) steps on switch (H) which heats electric iron (I) and burns hole in pants (J). Smoke (K) enters hole in tree (L), smoking out opossum (M) which jumps into basket (N), pulling rope (O) and lifting cage (P), allowing woodpecker (Q) to chew wood from pencil (R), exposing lead. Emergency knife (S) is always handy in case opossum or the woodpecker gets sick and can't work.
Checking for Understanding Evaluate (What levels of questioning are included here?) • Draw a first class lever. • Label fulcrum, resistance, effort. • Explain why what you’ve drawn is a machine. • Describe how friction plays a role in your machine.
Resistance = 3 units Effort = 1 unit 1 1 3 2 Effort x distance from fulcrum = Resistance x distance from fulcrum 1 x 3 = 3 x 1
Standards • What National Standards have been addressed in this lesson? • What VA SOL have been addressed in this lesson?