Simple Machines

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Simple Machines
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Simple Machines

• Simple machines are devices that make work easier
  by changing the amount or the direction of force.

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How Do They Help Us?

• Simple Machines can help by
• Increasing the force that enables us to lift
  heavy objects
• Changing the direction of the force that enables
  us to move objects in different directions
• Increasing the speed of a force to enable us to
  move things farther or faster.

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Six Types of Simple Machines

• 1. Inclined Plane
• 2. Wedge
• 3. Screw
• 4. Lever
• 5. Pulleys
• 6. Wheel and Axle

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Inclined Plane

• Consists of a plane surface which is tilted or
  inclined. Using an inclined plane to move a heavy
  object takes less force than lifting it directly.
  
• Examples include
• Ramp for loading and unloading
• a switchback road
• waterslide
• ladder

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Wedge

• Consists of two planes and is usually used to cut
  or to break things apart.
• Wedges move objects by being forced under or
  between them.
• They alter the direction of a force applied to
  them.
• When you push down on a wedge it pushes out on
  the two planes that it is in between.

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Examples of Wedges

• Log splitter (a wedge used with a sledge hammer
  to split logs)
• Axe heads
• Cutting edges of chisels, knives and scissors
• Points of nails, needles, and pins
• Tip of a screw driver
• Tines of forks
• Door Stops

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Screw

• Consists of an inclined plane wound around a
  post.
• Screws can lift things
• Examples
• Jack Screw
• Piano Stool
• nut and bolt

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Lever

• There are three types of levers that are
  classified according to their three parts
• Fulcrum (pivot point)
• Effort Arm
• Resistance Arm

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First Class Lever

• The Fulcrum is in between the resistance and
  effort.

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Examples of a First Class Lever

• Car Jack
• Crowbar
• Hammer Claw (used to pull out nails
• Balance for massing and weighing objects
• Hedge Trimmers
• Pliers

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Second Class Levers

• The resistance is between the fulcrum and the
  force

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Examples of a 2nd Class Lever

• Nut Cracker
• Garlic Press
• Wheelbarrow

Fulcrum
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Third Class Lever

• The force is in between the resistance and the
  fulcrum.

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Examples of a 3rd Class Lever

• Broom
• Tweezers
• Catapult
• Hockey Stick

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Pulleys

• Consists of a grooved wheel (or wheels) that
  spins on a fixed axis with a rope or chain moving
  over the wheel.
• There are two types of pulleys
• Fixed pulleys
• Movable pulleys

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Fixed Pulleys

• Wheel(s) and rope are fixed in place. They make
  lifting easier by changing a push to a pull.
• Examples
• clothesline
• flagpole
• mini-blinds
• Sailboats (to raise a sail)

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Movable Pulleys

• Wheel(s) and rope are attached to and move with
  the resistance.
• They make work easier by changing force.
• Example
• Block and Tackle
• Consists of fixed and movable pulleys
• It makes work easier by changing the direction of
  force and decreasing the force.

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Wheel and Axle

• Consists of a wheel that turns around a rod or
  axle.
• Turning one turns the other

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Wheel and Axle

• Examples
• airplane propellers, blades on a helicopter
• Doorknob
• Steering Wheel or handlebars
• Wheels on a car, bike, wagon, etc.
• Wheels and Axles with teeth that fit one another
  are called gears.

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Compound Machines

• Several simple machines working in conjunction
  with each other can create compound machines.

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Compound Machines

• Examples
• bicycle
• can opener
• cars and trucks
• pencil sharpener
• music box