The 6 Simple Machines
How do machines make work easier?
Simple Machines get the same work done by reducing the
size of the force needed by increasing the distance.
Inclined Plane
Screw
Pulley
Lever
Wedge
Wheel and Axle
Simple Machines
Simple machines make work easier for us by
allowing us to push or pull over increased distances
Simple Machines Booklet Project
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Fold 2 pieces of blank paper in half to make an
8 page booklet.
Format: (24 AP; 3 points per page)
• Page 1 – Cover Page
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Title, Colored Illustration, Author Information (name and
period)
Page
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Inclined Plane
Lever
Pulley
Screw
Wedge
Wheel & Axle
Definitions
For Pages 2 – 7
On each page, provide an
illustration of an example,
definition, and a descriptive
caption explaining how the
simple machine makes work
easier (20 word min).
Define Energy, Work, Force, Machine, Complex Machine,
Technology, Mechanical Advantage, and Efficiency
Definitions:
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Energy: The ability to do work
• Measured in Joules
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Work = Force x Distance
• Measured in Joules
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Force: A push or a pull
• Measured in Newtons
How do machines help you do work?
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Machine-any device that helps people do
work.
• Examples
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Technology-the use of knowledge to
create products or tools that make life
easier.
• Humans have been improving their lives for
thousands of years with technology.
• The simplest machine is an example of
technology.
How do machines help you do work?
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Machines make work easier by
• (1) changing the size of the force needed
or by
• (2) changing the direction in which the
force is exerted
1 pulley
W=Fd
More
distance so
less force
Much
easier than
lifting
4 pulleys
W=Fd
More
distance so
less force
Very little
force need
The 6 Simple Machines
Inclined Plane
Screw
Pulley
Lever
Wedge
Wheel and Axle
Inclined Plane
Inclined Plane
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The Egyptians used simple machines to build the
pyramids. One method was to build a very long
incline out of dirt that rose upward to the top of
the pyramid. Then blocks of stone were placed on
large logs (another type of simple machine - the
wheel and axle) and pushed slowly up the long
inclined plane to the top of the pyramid.
Inclined Planes
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Inclined plane - a
simple machine that
is a sloping surface.
W=Fd
Makes work easier
by increasing the
distance
The lower the slope
of a ramp the less
force needed to lift
the object.
Screw
•The screw is an inclined plane wrapped around a cylinder or cone
to form a spiral.
•It is used to raise and lower weights and hold objects together.
•Examples are drills, jar lids, nuts and bolts.
•The spiraling inclined plane that sticks out from the body of the
screw forms the threads of the screw.
•The threads increase the distance, which decreases the force
needed to turn the screw.
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Two inclined planes
joined back to back
Wedges are used to
split or hold objects
together
Examples: axe blade,
knife, chisel, door
jam
The thinner the
wedge, the less force
is needed to press it
into something
(knife)
Small surface area
means greater
pressure
• Thinner blades have
greater pressure
Wedges
Lever
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A lever is a solid bar that rotates, or turns,
around a fixed point.
The fixed point is called a fulcrum.
A lever can multiply the input force and
change the direction of the force.
The way in which a lever changes an input
force depends on the position of the fulcrum.
First Class Lever
• Common examples
of first-class levers
include crowbars,
scissors, pliers, tin
snips and seesaws.
Second Class Lever
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Examples of
second-class
levers include
nut crackers,
wheel barrows,
doors, and
bottle openers.
Third Class Lever
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Examples of
third-class levers
include tweezers,
arm hammers,
and shovels.
Wheel & Axle
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The wheel and axle act like a rotating
collection of levers.
The axle is like a fulcrum.
When the axle turns the wheel, there is
greater distance and therefore less force
that needs to be applied from the axle.
Wheel & Axel
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The axle is stuck
rigidly to a large
wheel.
Fan blades are
attached to the
wheel. When the axel
turns, the fan blades
spin.
Pulleys
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Pulleys are wheels and
axles with a groove
around the outside
The single pulley
makes work easier by
changing the direction
of the force
A pulley needs a rope,
chain, or belt around
the groove to make it
do work
Mechanical Advantage
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Mechanical
advantage (MA)
measures the
ratio of how much
the machine
changes the force.
Input force – the applied force
Output force – the resulting force
MA=Output force/Input force
Work Input and Output
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When work is
done energy is
transferred
• A machine
increases the
potential or kinetic
energy of an
object by doing
work on it.
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If distance
increases the
force decreases.
W=Fd
Efficiency
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Work input is the amount of work done on a
machine.
• Input force x Input distance
Work output is the amount of work done by a
machine.
• Output force x Output distance
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Output work is always less than input work.
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Efficiency is the ratio of a machine’s output work to
the input work.
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Efficiency (%) = Output work/Input work x 100
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• Friction
No real machine is 100% efficient because machines lose
energy to friction, which is why we lubricate moving parts and
used streamlined designs.
Compound Machines
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A machine that is made of two or more
simple machines is called a compound
machine.
Gears are an example of a compound
machine (2 wheel & axles).
The mechanical advantage of a
compound machine is the product of
their mechanical advantages.
Example: the mechanical advantage of
a pair of scissors is the product of its 2
levers and 2 wedges.
GEARS-Wheel and Axel
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Each gear in a series
reverses the
direction of rotation
of the previous gear.
The smaller gear will
always turn faster
than the larger gear.
Combined Pulley
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A multiple pulley
system makes work
easier by changing the
distance over which
work is done and
therefore decreases
the force required.
The main
disadvantage is it
travels a very long
distance.
Rube Goldberg Machines
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Rube Goldberg machines are
examples of complex
machines.
All complex machines are
made up of combinations of
simple machines.
Rube Goldberg machines are
usually a complicated
combination of simple
machines.
By studying the components
of Rube Goldberg machines,
we learn more about simple
machines
Safety Device for Walking on Icy Pavements
When you slip on ice, your foot kicks a paddle (A),
lowering finger (B), snapping turtle (C) extends neck
to bite finger, opening ice tongs (D) and dropping
pillow (E), thus allowing you to fall on something soft.