Download Examples of Wheel and Axles

Vocabulary
• A wheel is a lever that can turn 360 degrees
and can have an effort or resistance applied
anywhere on that surface. The effort or
resistance force can be applied either to the
outer wheel or the inner wheel (axle).
• An axle is the spindle on which one or more
wheels revolve.
More Vocabulary for Wheels
and Axles
• Resistance is the force we are trying to
overcome.
• Effort is the forces we use to overcome
resistance.
• The fulcrum is the point or support about
which a lever turns.
A wheel and axle is a lever that rotates
in a circle around a center point or
fulcrum. The larger wheel (or outside)
rotates around the smaller wheel
(axle). All wheels need an axle. The
wheel and axle must move together to
be a simple machine.
wheel
A wheel and axle lifts or moves loads.
Bicycle wheels, Ferris wheels and gears
are all examples of a wheel and axle.
• Wheels can also have a solid shaft with
the center core as the axle such as a
screwdriver or the log in a log rolling
contest.
More Examples?
• Turn to your friend to see if you can find
more examples of where you could find
wheels and axles.
How about…
Did You Know?
• The wheel and axle is a type of lever.
If the wheel is turning the axle, it’s a
type of second-class lever. The radius
of the axle is a resistance arm. The
center of the axle is the fulcrum.
• A wheel is a lever that can turn 360
degrees and can have an effort or
resistance applied anywhere on that
surface.
• The effort or resistance force can be
applied either to the outer wheel or the
inner wheel (axle).
If effort is applied to the
wheel, it turns the axle.
They both move together.
The larger the wheel the
greater the force over the
distance of the axle. This
is evident in steering
wheels and doorknobs.
Resistance
Effort
Fulcrum
Effort
Fulcrum
Resistance
If effort is applied to the
axle, the wheel turns.
Examples include vehicle
wheels, motorized fans and
circular saws.
Wheel and Axle Demo
• 2 volunteers
• 1 meter stick
• Student 1 firmly grasps meter stick in the center with one
hand. Students arm acts as the axle.
• Student 2 places hands immediately next to the center
hand. Student 2’s hands represents the edges of the
wheel.
• Student 2 gently tries to turn the stick wheel. Class pays
attention to the force needed to turn the wheel.
• Student 2 moves his hands out from the axle. Predict
what will happen.
Trade-off?
• What was the trade off in the
demonstration?
• How do you think you find out the MA of a
wheel and axle?
Discussion
• The wheel is larger than the axle. It moves a
greater distance than the axle. Because of this, it
multiplies the force applied to the azle but
always requires a trade off of the wheel moving
a greater distance.
• Changing the diameter of either the wheel or the
axle controls the MA. As the diameter of the
wheel increases (the axle stays the same) the
MA increases and a greater force is applied to
the axle.
MA Formula
Two Machines in One?
A wheel and axle is really two
machines in one because you
can use each part in different
ways.
Two Machines in One?
The first way is to roll something along.
Wheels help you move an object across the
ground because they cut down on the
amount of friction between what you're
trying to move and the surface you're
pulling it against. (The axle is the object
that attaches the wheel to the object it's
moving.) Since only the very bottom of the
wheel touches the ground, there is less
surface area to rub — and less friction.
Imagine pulling a little red wagon without
any wheels! Generally speaking, the bigger
the wheel, the easier it is to make
something roll.
Two Machines in One?
The second way of using a wheel is like a
round lever. A door knob or a faucet on a
sink are really round levers, and the
"fulcrum" is in the middle where the axle
turns. Imagine if a door knob was replaced
with a little rod. It would be much harder to
open the door! Once again, there's a tradeoff: The larger the diameter of the
wheel, the less effort you need to
turn it, but you have to move the
wheel a greater distance to get the
same work done.
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Completion Date: 2008
Height: 169 meters (555ft)
(equivalent to 42 story building)
Diameter: 150 meters (492 ft)
Duration of ride:
37 minutes. The ride will be
operational 16 hours a day.
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Capsules:
Comprises 28 fully airconditioned and UV protected
capsules that can comfortably
carry 32 people each (max 36).
References
Information used from and credited to the following websites:
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http://www.sirinet.net/~jgjohnso/simple.html
http://forum.skyscraperpage.com/showthread.php?t=102884
http://www.usoe.k12.ut.us/curr/science/sciber00/8th/machines/sciber/machine7.htm
http://sln.fi.edu/pieces/knox/automaton/wheel.htm
http://teacher.scholastic.com/dirtrep/simple/wheel.htm
http://www.msichicago.org/ed/scienceminute/ScienceMinute4.06.pdf
http://www.lessonplanspage.com/ScienceSimpleMachines-WheelAxle46.htm
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Main Ideas for this PowerPoint came from:
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Lindsay Easterly
Amanda Fox Turner