Rube Goldberg Machine Design Contest
Teacher Training
Jean Zheng
Massachusetts Institute of Technology
Department of Mechanical Engineering
January 29, 2005
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Topics
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Engineering problem solving process
Measurement Systems
Statics and Dynamics
Energy
Springs
Collisions
Friction
Formulas
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Engineering Problem Solving Process
1.
2.
3.
4.
5.
6.
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8.
Identify the problem
Make observations related to the problem
Propose a root cause for the problem
Design an experiment to test the hypothesis
Run “dry lab experiment” before actual experiment
Carry out actual experiment
Analyze data and draw conclusions
Solve problem, or formulate another cause for the
problem and repeat steps 4-8 until problem is solved
Example: “My computer mouse has become ‘lethargic’ and unresponsive
recently. When I move my mouse, often the cursor on the computer screen
won’t move with it.”
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Measurement System
• English – commonly
used in the US
• Metric – adopted by
the rest of world
• 1 mile = 1760 yards
1 yard = 3 feet
1 foot = 12 inches
• 1
1
1
1
kilometer = 1000 meters
meter = 10 decimeters
decimeter = 10 centimeters
centimeter = 10 millimeters
Both systems can be used to measure length, area, volume,
time, liquid capacity, velocity, acceleration, force, mass,
weight, etc.
Choose one system and stick to it! (NASA incident)
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Statics and Dynamics
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Statics – things that are in equilibrium
Dynamics – things that are in motion
Newton’s Laws of Motion
v
– In the absence of any external forces, an object will
continue doing what it was doing
– Force is the rate of change of the momentum of an
object, which is equivalent to the mass of an object
times its acceleration (F=ma)
– If one object exerts a force on another object, the
second object will exert an equal and opposite force
back on the first object
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Energy
• Total energy is conserved, but
can be transferred/converted
from one form to another
• Many forms of energy!
• Potential energy – energy an
object has in its current state
• Kinetic energy – energy of object
in motion
• Many ways of storing energy!
• Many ways of transferring
energy!
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Springs
• Forces and energies!
• Displacement is linearly
proportional to force
applied (F=kx)
• Total energy stored =
0.5kx2 (potential energy)
• Common uses: car shock
absorbers, screen door
pistons, mousetraps
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
x
F
January 29, 2005
Collisions
• Transfer of energy
• Collisions can be perfectly elastic, elastic, or
perfectly inelastic
– perfectly elastic: mechanical energy conserved during
the collision, objects do not stick together
– elastic: mechanical energy not conserved, objects stick
together for a brief moment
– perfectly inelastic: mechanical energy not conserved,
objects stuck together after collision
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Friction
• Dissipative force
• Opposes direction of motion
• Friction constant different between different
contact materials and surfaces
• Depends on surface area contacted
• Various forms (heat, sound, etc)
• Design machines with friction in mind!
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Formulas
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Newton’s Second Law of
Motion
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Conservation of
Mechanical Energy
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Potential Energy
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Kinetic Energy
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Spring Force
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Spring Energy
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Momentum (collisions)
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Friction
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Conclusion
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Physics is now your new best friend
Double-check your calculations
Planning is everything
Teamwork is also everything
Design for manufacturability, accuracy, and predictability
• Have fun with the contest!
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005
Additional Resources
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High school physics books
Other teachers at your school
MIT student mentors
MIT Museum
www.rube-goldberg.com
Other online resources
Teammates!
Jean Zheng, MIT Museum
Rube Goldberg Machine Design Contest
January 29, 2005