Simple%20Machines

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Simple Machines
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A Simple Machine?

• Simple machines help us do work.
• Machines make work easy.

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So What?

• Simple machines make work easier
• Simple machines either change the amount of force
  on an object or change the direction of the force
• Machines DONT diminish the amount of work we
  dothey just make it easier!
• Two or more SIMPLE machines make a COMPLEX
  machine!

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What is mechanical advantage?

• The number of times a machine multiplies the
  effort or input force.

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Mechanical Advantage

• It is useful to think about a machine in terms of
  the input force (the force you apply) and the
  output force (force which is applied to the
  task).
• When a machine takes a small input force and
  increases the magnitude of the output force, a
  mechanical advantage has been produced.

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What is a Simple Machine?

• Simple machines have few or no moving parts.
• There are 6 kinds of simple machines.

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What are the 6 kinds of simple machines?
Inclined plane 2. Wedge 3. Screw Wheel and axle 5. Pulley 6. Lever
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An Inclined Plane?
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Actually, an Inclined Plane

• inclined plane is like a flat board that is
  higher on one end.

• inclined plane makes work easier.

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Inclined Plane

• An inclined plane is a slanting surface.
• This is because your effort is spread out over a
  larger distance.
• Lifting an object to the same height requires A
  LOT MORE effort over a shorter distance

It is easier to push an object up an inclined
plane than to lift the object the same height
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Inclined Plane
Shorter distance
Longer Distance
MORE EFFORT
LESS EFFORT
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Can you think of some other inclined planes?
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A Wedge?
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Actually, a wedge

• is two inclined planes pushed together like a
  V.
• pushes things away from each other.
• split things.

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Wedge

• A wedge has one slanting slide that ends in
• a sharp edge which can cut things apart.

A wedge is an inclined plane that decreases the
force needed to break apart something.
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Can you think of some other wedges?
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A Screw(ge)?
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Actually, a screw

• is an inclined plane wrapped around a post or
  cylinder (the inclined plane allows the screw to
  move itself when rotated).
• holds things together and can make them go up
  and down.

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To help you visualize this better

• of Threads is equal to Length of the inclined
  plane

Picture from http//www.nvsd44.bc.ca/sites/Reports
ViewOnePopM.asp?RID3812
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Can you think of some other screws?
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Wheels and axles?
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Actually, a wheel and axle

• is a pole that goes through the wheel which
  allows the wheel to turn

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Can you think of some other wheels and axles?
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Pulleys?
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Pulleys

• A pulley uses wheels and rope to raise, lower or
  move a load.
• A pulley is made up 3 parts

Pulleys make lifting a load easier by changing
the direction of your effort force
Pulley
Load
Effort (force)
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Parts Of A Pulley
Pulley
Effort (force)
Load
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Types of Pulleys

• There are different types of pulleys.

Single Pulley
Moveable Pulley
One wheel involved
Multiple wheels involved
Doesnt increase the effort force changes the
direction
Multiplies the force based on number of strings.
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Can you think of some other pulleys?
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Lever?
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Lever

• A lever is a bar that rests on a pivot.
• Levers are made up 4 parts

Levers make it easy to lift things because they
magnify our effort
Lever
Fulcrum
Load
Effort
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Parts of Lever
Lever
Bar of stiff material
Load
The mass to move
Fulcrum
Effort
The pivot
Force of the person
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Class One Lever

• There are 3 major classes of levers
• Fulcrum is in the middle between the load and the
  effort

Class ONE
a seesaw
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Class Two Lever

• There are 3 major classes of levers
• Class TWO
• The load is in the middle
• Fulcrum and effort at opposite ends

Class TWO
a wheelbarrow
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Class Three Lever

• There are 3 major classes of levers
• Effort is in the middle
• between the load and the fulcrum

Class THREE
tweezers, your arm
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Can you think of some other levers?
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What is a Lever?

• a rigid bar that is free to turn about a fixed
  point called the fulcrum
• Every Lever has three (3) parts

Effort Where force is placed.
Resistance Object that is moved
Fulcrum Pivoting Point
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Efficiency

• Efficiency is the ability of a machine to convert
  input work to output work.
• The efficiency of a real machine is always less
  than 100 percent because of friction.

Efficiency output work ? 100 input work
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Calculating Efficiency
Always express the number as a
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Efficiency

• Oil, or another lubricant, can increase
  efficiency by reducing the number of contact
  points between surfaces.

Friction reduces efficiency by converting some
work into heat.
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Simple Machines

• Simple machines can be put together in different
  ways to make complex machinery

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COMPOUND MACHINES

• Many familiar compound machines, such as a car, a
  washing machine, or a clock, are combinations of
  hundreds or thousands of simple machines.

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Compound MachineCorkscrew

• Inclined Plane
• Wedge
• Screw
• Lever
• Wheel and Axle

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Compound MachineJack

• Inclined Plane
• Wedge
• Screw
• Lever

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A Wedge in a Compound Machine Stapler

• Staples are wedges they cut through paper
  because their ends are pointed in a wedge shape.
• Simple machines in a stapler
• Wedge
• Lever

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A Wedge in a Compound Machine Scissors

• The cutting edge of scissors is a wedge.
• Simple machines in a pair of scissors
• Wedge
• Lever

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What type of machine?

• video

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Vocabulary
Simple machine mechanical advantage
lever Fulcrum inclined plane pulley Screw
wedge wheel axle Output force Input
force compound machine