Machines Made
Simple
Chapter 14
Simple Machines
Ancient people invented simple machines
that would help them overcome
resistance forces and allow them to do
the work against those forces.
2
Simple Machines
• A simple machine is a machine that
does work with only ONE movement
• Six basic types
• Designed to make work easier, faster,
or to change the direction of the
force
• Few or no moving parts
• Combine to form more complex
machines (i.e. compound machines)
Compound Machines
• A machine made up of 2 or more
simple machines is called a compound
machine
• Examples: scissors, pencil sharpener,
car, microwave, oven
Inclined Plane
Inclined Plane
• An inclined plane is a flat, sloped surface
• Longer and less steep = smaller force
needed
• Shorter and more steep = larger force
needed
EXAMPLES: ramps, hillside roads, stairs
Wedge
Wedge
• A wedge is two inclined
planes put together and
has a cutting edge
• EXAMPLES: axes, door
stops, your front teeth,
scissors, knife blades
Screw
Screw
• A screw is an inclined plane wrapped
around a cylinder or post (inclined plane
forms screw threads).
• A screw holds things together
EXAMPLES: jar lid, screw, drill bit
Lever
Lever
• A lever is any rigid/stiff rod or plank
that pivots, or rotates, about a pivot
point (called the fulcrum).
• EXAMPLES: hammer, rake, nut
cracker, tweezers, scissors, crow bar,
broom
Pulley
NSF North Mississippi GK-8
Pulley
• A pulley consists of a
grooved wheel with a
rope or cable wrapped
over it.
• A pulley changes the
direction of the applied
force.
• EXAMPLES: used on
flagpoles, used on sails
on a boat, used in cranes
Wheel and Axle
Wheel and Axle
• A wheel and axle consists of two
circular objects of different sizes
that are attached in such a way that
they rotate together.
• EXAMPLES: a fan, ferris wheel,
doorknob, car wheel, screw
driver
Simple Machines
Eduardo is helping his family
move out of their old house.
Help him decide which task
would be easier, and then help
him figure out what simple
machine makes the job easier.
Eduardo has to move some heavy
boxes into the moving truck.
A
B
B would be easier because a ramp is an inclined plane.
Eduardo has to move a heavy box
a long distance.
A
B
A would be easier because the wagon has wheels and axels.
Eduardo needs to tear off a piece
of packing tape.
A
B
B would be easier because the edges of the scissors
are wedges.
Eduardo needs to move a heavy box
to his room on the fourth floor.
A
B
B would be easier because Eduardo is using a pulley.
Eduardo needs to help his father
move the refrigerator.
A
B
A would be easier because the dolly is a lever
(with wheels and an axel).
Eduardo needs to help his father change
a flat tire on the moving truck.
A
B
B would be easier because a jack uses a screw.
Now that Eduardo and his
family have reached their new
house, they need some help in
unpacking their belongings.
Help Eduardo decide on the
best simple machine to use in
each situation.
Eduardo needs to open the boxes his
mom sealed with packing tape. What
simple machine should he use?
Eduardo should use a wedge (probably a pair of scissors).
The door to the moving truck is
jammed shut. What simple machine
might Eduardo’s father use to open it?
Eduardo’s father should use a lever (most likely a crowbar).
Eduardo needs to carry the boxes out
of the moving truck. What simple
machine will make this easier?
Eduardo needs an inclined plane (a ramp) to carry the boxes
out of the truck.
There is a flagpole outside Eduardo’s
new school. What simple machine could
be used to raise and lower the flag?
A pulley is used to raise and lower the flag.
Eduardo’s mom wants to hang a cabinet
in the new kitchen. What simple
machine might she use to attach it to
the wall?
Eduardo’s mom could use a screw to attach the cabinet to the
wall and hold it in place.
Eduardo helped his father install
doorknobs in the new house. What
kind of simple machine is a doorknob?
A doorknob is a wheel and axel.
Simple Machines
Lever
Wheel and axel
Wedge
Screw
Inclined plane
Pulley
Identifying Simple Machines
Inclined plane / Lever
Screw
Wheel and axel
Pulley
Wedge
Inclined plane
Image Sources
<http://etc.usf.edu/clipart>
<http://www.oz.net/~peragine/doorknob.jpg>
<http://www.theteachersguide.com/clipart/scissors.gif>
<http://www.weprintcolor.com/stockimages/construction/images/Bl
ack%20metal%20crowbar.jpg>
<http://67.19.222.106/military/graphics/flagpole.jpg>
<http://www.morris.umn.edu/UMMimages/public/images/campus_mi
sc/flagpole.jpg>
<http://www.phillips-screw.com/images/homeMain.jpg>
<http://mws.mcallen.isd.tenet.edu/mchi/ipc/ch15htm/images15/Scr
ew.jpg>
<http://www.discountramps.com/handi-van_ramp.gif>
http://staff.harrisonburg.k12.va.us/~mwampole/1resources/simple-machines/flag-pole.jpg
NSF North Mississippi GK-8
Images Sources (cont.)
<http://www.physics.uwaterloo.ca/demo/bikewheelgyro.
html>
<http://www.piratescave.co.uk/about_us.htm>
<http://staff.harrisonburg.k12.va.us/~mwampole/1resources/simple-machines/handicap-ramp.html>
<http://library.thinkquest.org/J002079F/wedge.htm>
<http://www.idahoptv.org/dialogue4kids/season7/simple
machines/facts.html>
<http://www.scienceclarified.com/Io-Ma/MachinesSimple.html>
NSF North Mississippi GK-8