Characteristics_of_Efficient_Simple_and_Compound_Machines_Science8.pptx

Characteristics_of_Efficient_Simple_and_Compound_Machines_Science8.pptx

• 1.
  Characteristics of EfficientSimple and Compound Machines Science 8
• 2.
  Learning Objectives • •Explain machine efficiency • • Identify characteristics of efficient simple and compound machines • • Appreciate their importance
• 3.
  Review • Simple machines:Lever, Wheel & Axle, Pulley, Inclined Plane, Screw, Wedge
• 4.
  What is MachineEfficiency? • Efficiency = (Useful Output Work / Input Work) × 100% • No machine is 100% efficient due to friction.
• 5.
  Characteristics of Efficient Machines •• Reduces effort • • Saves time • • Minimizes friction • • Properly aligned parts • • Durable materials • • Well-maintained • • Less energy wasted
• 6.
  Simple Machines • Lever •Wheel & Axle • Pulley • Inclined Plane • Screw • Wedge
• 7.
  Compound Machines • Twoor more simple machines working together. • Examples: Bicycle, Scissors, Wheelbarrow, Can opener, Egg beater
• 8.
  Factors Affecting Efficiency •• Friction • • Lubrication • • Maintenance • • Material quality • • Proper use
• 9.
  Activity • Identify whethereach object is a simple or compound machine and explain how it can be made more efficient.
• 10.
  Assessment • 1. Whatis machine efficiency? • 2. Why can't machines be 100% efficient? • 3. Give 3 characteristics of efficient machines. • 4. Give 2 examples each of simple and compound machines.
• 11.
  Thank You • Questions?