Wheel and Axle
Lever
Pulley
Screw
Inclined Plane
Wedge
In your journal
 In
the table of contents title it “Simple
Machines”.
 Go to the next clean page and title it
simple machines as well.
 When we are done taking notes, you
will glue it into your journal
What is a machine??
A simple machine is any tool that helps us
do work.
Machines help us by:
1. Changing the amount of force on an
object.
2.
Changing the direction of the force.
The 6 Simple Machines
Inclined Plane
Screw
Pulley
Lever
Wedge
Wheel and Axle
We will focus on:
 Inclined
 Pulleys
planes
So…what is a simple machine
and what makes them so
simple ?

A simple machine
has few or no
moving parts.
 They often use only
the force (effort) of a
person to do the
work.
 Simple machines
make this work
easier.
Why are they so important??
Simple machines are
important because they can
make a physical job easier
by changing the magnitude
(amount of work) or the
direction of the force
exerted to do work.
So, they make work easier?
 Yes!
 Simple
machines let you do work using
less force.
 The amount of force output is greater
than the size of the force you put in.
 What?
Have you ever…
 Tried
to push a screw into wood with
your bare hands?
 Could you do it?
 Turning the screw into the wood using
a screwdriver is much easier!
 Using a screwdriver (the simple
machine) increased the amount of
force you used, allowing you to put the
screw into the wood.
Well…
 The
screw driver is an example of a
wheel and axle, where the screw is the
axle and the handle is the wheel. The
tool makes the job easier by changing
the amount of the force you exert.
Wheel
Axle
Let’s review some important
terms!
Important Terms to know:
– a push or pull
 Energy – is the ability to do work.
 Work – is the result of force moving an
object
 Effort – The force you apply to a simple
machine.
 Load – the object being moved
 Simple Machine – devices that reduce
the amount of work needed to move an
object.
 Force
What is work again?
 In
science WORK does not mean go to
a job and get a paycheck.
 It means that a force ( your effort) was
used in order to move an object
 Example, it takes work to move a
bookshelf across the room.
Work input and output
Work
input is the amount of
work done on a machine.
Work
output is the amount of
work done by a machine.
Formula
for Work:
Work = force x distance
Inclined Plane
How did
Egyptians build
such large
pyramids?
Inclined Plane

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 very gently. The blocks of stone were
placed on large logs (another type of simple machine
- the wheel and axle) and pushed slowly up the long,
gentle inclined plane to the top of the pyramid.
Inclined Planes

An inclined plane is a
slanted surface that
makes work easier.
 You can use an
inclined plane to help
move an object to a
higher place or a lower
place.
 The disadvantage is
that you have to move
it a farther distance.
 Examples: Ramp,
stairs, slides
Wheel
Rope
This box is easier to
lift because of the
pulley. Click on it to
learn more.
Pulleys

A pulley is a simple
machine with a wheel
and with a rope.
 There is a groove on
the wheel. This groove
allows the rope or
chain to not fall off the
wheel.
 You can use a pulley
to lift a load up, down
or even sideways!
Pulley Examples:
Flag pole
Fishing reel
Clothing line
Crane
Pulleys
Pulley system – a group of two or
more pulleys that work together to lift a
load.
A
fixed pulley is anchored to a single
spot. It can rotate but does not move
up or down.
 A moveable pulley is free to move up and
down.
Types of Pulleys
1.Fixed Pulley:
A fixed pulley changes the direction
of a force; you pull down on the
rope and the load goes UP!
The effort needed to lift this load is
equal to the weight of the load.
This is because the load is
supported by only 1 rope.
You must also pull a length of rope
equal to the distance you wish to
lift the load.
Types of Pulleys
2. Movable Pulley:
This pulley system
provides Mechanical
Advantage,
requiring only ½ the
effort needed to lift
the weight of the
load. If the load
weighs 20 lbs, only
10 lbs of effort is
needed to lift it. Can
you tell why?
Movable Pulleys (cont’d)
The load is supported by 2 rope
“arms” under the pulley. Each load
arm supports half the weight of the
load, so the arm pulling up uses
only 10 lbs of effort to lift this load.
You must pull twice as much rope
to lift the load a certain distance.
Example: Pull 2 ft of rope for each
1 foot of height that you want to lift
the load.
Combined Pulleys

The effort needed to
lift the load is less
than half the weight
of the load.
 The more pulleys,
the less amount of
work you need to
apply.
Combining fixed and moveable pulleys makes a
Compound Pulley System. This allows the user to gain
both Mechanical (less effort to lift) and Directional
Advantage.
The more rope arms supporting the load the greater the
Mechanical Advantage, so less force or effort is needed
to lift the load.
Your notes should be complete
now.
 Check
and see if there are any
blank spots.
 Ask your neighbor for help if you
are missing anything.
Get the 2 overview pages
 Pulley
Pull Ups
 Simply machines
 Get
out a highlighter or colored pencil.
Read through these pages.
Quiz slides (if time)
 Go
to next slide
A pulley system is helpful
because it decreases the
______________________.
Choose one:
 A.
amount of effort needed to lift an object
 B. amount of rope needed to lift an object
 C. weight of the object
 D. height that the object needs to be lifted
A pulley system is helpful
because it decreases the
______________________.
Choose one:
 A.
amount of effort needed to lift an object
 B. amount of rope needed to lift an object
 C. weight of the object
 D. height that the object needs to be lifted
Which pulley system will allow the chair to
be lifted with the least amount of effort?
Answer
Explanation: The greater the
number of ropes sharing the
weight, the smaller the effort
required to lift an object.
Notice that with system D the
weight of the chair is shared by
6 ropes.
An effort of just over 1/6 the
weight of the armchair is
needed to lift it with this system.
Your notes should be complete
now.
 Check
and see if there are any
blank spots.
 Ask your neighbor for help if you
are missing anything.
Get the 2 overview pages
 Pulley
Pull Ups
 Simply machines
 Get
out a highlighter or colored pencil.
Read through these pages.