the 1980’s mullet-loving, hockey-playing, world-saving, problem solver of the
TV show by the same name.
In EVERY single episode, MacGyver
would use his knowledge of chemistry, biology, physics and general science,
along with his trusty Swiss Army knife, to get himself out of a jam and usually
avert a major international crisis.
While we all know that TV rarely portrays life accurately, in this
instance, the show MacGyver is a great illustration of how a better
understanding of science has practical application and benefits in our everyday
lives, even if our everyday life doesn’t involve preventing WWIII or the fall
of the free world.
Today I am going to explain simple machines
and how they help you have a little MacGyver magic of your own. Most people
believe that a machine is a complex and intricate device such as a car engine
or a generator. However, according to eSchoolToday.com, “A
machine is any device that does work.” MacGyver’s Swiss Army knife, for
example, included multiple simple machines such as the corkscrew, knife, screwdriver,
awl, scissors, tweezers, and toothpick that helped him work. So, what is a good definition of work? Work occurs when
force is applied to an object and the object moves. (Again, with emphasis) Work occurs when force
is applied to an object and the object moves. Machines make work
easier by reducing the amount of force needed to accomplish a task. Simple
machines have been used from antiquity all the way up to modern day and there
are a few parameters that need to be defined. To begin with, we must understand
that a simple machine does not do work on its own. A simple machine increases the force or effort that a
person uses. Also, a simple machine does not use electricity and has one or
fewer moving parts. The six simple machines are: the incline plane, wedge,
screw, lever, wheel and axle, and pulley. (pictures of each machine on board).
Let’s start with the incline plane.
This simple machine has no moving parts. The incline plane is a sloping
surface. This plane allows us to move objects to a higher or lower surface with
less energy than if we lifted the object directly upward or lowered it
downward. Most archeologists believe that the ancient Egyptians used incline
planes to move heavy stones when building pyramids. Another name for an
inclined plane is a ramp. Stairs are also considered an incline plane.
With the incline plane if the slope
is gentle it is easy for a person to push or pull something up or down the
incline plane. However, the person will be pushing or pulling the object a
longer distance. If the slope is steep the person will need to exert more effort
to push or pull the object up or down the slope however the distance will be
In one MacGyver episode,
he used a pipe on some stairs to trip up his pursuers. Not a very fun way to go
down an incline plane.
Next is the wedge. The wedge is a triangular
tool. It is wide on one end and tapers to a point, thin
edge or sharp edge on the other end. Many times the wedge is attached to a
handle. This makes it easier to move. Some examples of the wedge are knives,
nails, axes, and doorstops. Wedges have been used since the creation of man.
Rocks were attached to wooden sticks to make crude axes and spears. The bow and
arrow utilize a wedge for the tip of the arrow, and swords are another wedge
used in ancient times. Every time MacGyver used his Swiss Army knife he was
utilizing a wedge. The wedge works by changing the direction of the force that
As you can see, the force of the ax
is driven down into the wood. Though the initial force is driven downwards, the
wedge directs the force sideways as it drives into the wood.
Let’s move on to the screw. Technically
the threads are an inclined plane wrapped around a cylinder. The distance
between the threads is called pitch and different screws have different
pitches. The closer together the threads are the easier it is to drive in the
screw. However, though it may be easier to drive the screw in with threads that
are closer together, it will take many more turns to screw it in. The wider the
pitch the harder it is to drill the screw into the object, meaning it will take
more effort, but fewer turns.
can push or pull objects together and hold them together. A screw can also lift
heavy objects. Modern day examples of screws we see every day are bolts, jar
lids, violin string adjusters, water faucet valves, and corkscrews. The famous
Greek inventor Archimedes who lived in the 3rd century B.C. used a very
large screw in a cylindrical pipe to raise water through the pipe. It was
generally moved by a hand crank, as the screw turned it would bring water up
the pipe. Originally it was used for piping water out of ships. Later it was
used for irrigation systems. The invention is still used today in sewage
treatment plants and to bring cement out of cement trucks.
Levers are the fourth simple
machine we are going to talk about. The lever uses a rigid beam or plank that
is free to rotate on a pivot point. The lever is a great simple machine to move
heavy objects. Examples of the lever are seesaws, crowbars, oars, pliers,
scissors, tweezers, and shovels. In the ancient world, the catapult was a lever
that was used in warfare. Archimedes said, “Give me a place to stand, and I
will move the world.” In this quote, Archimedes was referring to the principle
of the lever and fulcrum. (http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/archimedes-and-simple-machines-moved-world)
The lever works when
effort applied to one end of the lever causes it to pivot on the fulcrum. This
produces the output or lifting of the load. Work is made easier with the lever
because it both increases the input force and changes the direction of that input
force. MacGyver made a lever in one episode and used it to lift a locked door
off its hinges.
The wheel and axle include two
circular objects. A smaller disc and larger disc that is joined at their
centers. The smaller disc is called the axle and the larger disc is called the
wheel. Two wheels joined to a single axle is also a simple machine. However,
just an axle or just a wheel is not a simple machine. Gears are simply wheels
and axles with teeth. Today we use the wheel and axle in doorknobs, steering
wheels, and egg beaters. In ancient times wheels and axles were used in things
such as chariots, carts, and the pottery wheel.
The wheel and axle work in one of
two ways. Either the force is applied to the wheel or the force is applied to
the axle. An example of applying force
to the wheel is the doorknob. Have you ever tried to turn the square axle
inside the doorknob when the knob has been removed? It is very hard to do so.
However, when the knob or wheel is on that little square axle it is easy to
turn the axle and open the door.
An example of the axle being turned is a
fan. MacGyver once used a spatula taped to a ceiling fan, to mimic the sound of
a helicopter flying overhead.
we get to the sixth and final simple machine, the pulley. A pulley is used to
lift or lower objects
when force is applied to the other end of the rope. An example of this is a
flagpole. The Egyptians are believed to have created the pulley.
multiple pulleys together to create a compound pulley. The more pulleys that are used the less
effort is needed to move an object. These systems, like the block and tackle,
are very common at constructions sites.
Simple machines have been used
since ancient times and are still used by you every day of your life. Whether
it is walking up a ramp (incline plane), cutting up a tomato with a knife
(wedge), opening a jar (screw), flinging food at your children with a spoon
(lever), opening a door with a doorknob (wheel and axle), or raising or
lowering your blinds (pulley), we use simple machines every day. The more you
understand about simple machines the more uses you will find for them… in
other words, the more you can “MacGyver” something when the need
arises. So, the next time you approach a
task, think about the types of simple machines you can and will use to make
that task easier to accomplish.