simple machines
DESCRIPTION
Simple Machines. Machine – a tool that helps us do work with less force. Machines help us by: Changing the amount of force on an object. Changing the direction of the force. Lever Inclined Plane Wedge Screw Wheel and Axle Pulley. Six basic simple machines :. - PowerPoint PPT PresentationTRANSCRIPT
Simple Machines
Machine – a tool that helps us do work with less force
Machines help us by:1. Changing the amount of force on an
object.
2. Changing the direction of the force.
Six basic simple machines:
• Lever
• Inclined Plane
• Wedge
• Screw
• Wheel and Axle
• Pulley
LEVER A bar that pivots on top of a fixed point called a fulcrum. It is used
to lift or move a load.A lever operates on the principle that a force applied at
one point lifts a resistive weight at a second point by rotating it about the fulcrum.
There are three classes or types of levers.
Lever examples: a seesaw, crowbar, baseball bat, rake, hammer, shovel, tweezers
Three Classes of Levers
An example of a first class lever is a seesaw.
An example of a second class lever is a wheelbarrow.
An example of a third class lever is a fishing pole.
Lever Video
INCLINED PLANEA slanted flat surface with one
end raised higher than the other. An inclined plane makes it easier to slide a load up or down rather
than having to directly lift it.There are no moving parts in an inclined plane.
Examples: ramp, stairs, slide, roof, escalator, gangplank,
driveway
Inclined Plane Video
WEDGE Two inclined planes put together.
A wedge is used to raise an object or split an object.
Examples: knife, doorstop, ax, needle, pin, nail, saw
Wedge Video
SCREWAn inclined plane wrapped
around a pole or cylinder. A screw is used to hold materials
together.
Examples: drill bit, screws, spiral staircase, corkscrew, meat grinder
Screw Video
WHEEL AND AXLEA wheel with a rod called an axle through the center. The wheel turns on the axle to help lift or
move a load quickly and easily.Examples: steering wheel,
doorknob, screwdriver, tractor wheel, car, pencil sharpener, bike
Wheel and Axle Video
PULLEY A wheel with a rope or chain
wound around it. A pulley can move a load up or down or
change the direction of a force.Examples : flagpole, clothesline, cranes, fishing reel, sailboat mast
Pulley Video
Scenario 1
• I have a bucket of paint I need to get to the painters on the third floor of a building. What simple machine would be best for the job and why?
Scenario 2
• I need to chop a piece of wood, so it will fit in my fireplace. What simple machine would be best for the job and why?
Scenario 3
• My grandmother is in a wheelchair and needs to get on stage for a performance. What simple machine would be best for the job and why?