By: Daniel Worstell
He was an inventor/cartoonist who is known
for his cartoons of extremely complicated
machines designed to perform ordinary,
mundane tasks. The humor in these diagrams
was because of the fact that they could be
completed in a much simpler manner, but the
complexity required delicate attention to detail
when creating such machines. Every year, a
number of “Rube Goldberg machines” are
created by people emulating his cartoons.
Goldberg also worked as an inventor, engineer,
author, and sculptor during his lifetime.
Goldberg was inspired to begin drawing his
machines came from his studying engineering at
UC Berkeley, and the beginning of the “machine
age” in the United States. This was a period of
rapid industrial development, marked by the
creation of complex machines to simplify life,
and his work was a sort of satirical take on the
development of life.
Inspired by Mr. Goldberg’s art, I decided to take a shot at
emulating his famous cartoons. Successful completion of the
machine required knowledge in a number of fields of Physics,
listed below:
-Hydraulics
-Standard Mechanics
-Simple Machines and their applications
-Gravity, its effect on objects, and its strength relative to other
forces such as friction
-Centripetal forces and their manifestations through objects
such as pendulums/circular motion
-Inclined Planes and their effects on motion
-One dimensional and two dimensional kinematics
-Collisions
-Limiting error and error analysis
-Electrodynamics
-Magnetism
To get this project done, it took months. I had
to allow myself enough time each week to do 45 steps, and continuously seek out sources of
error.
Steps 1-5 were completed
1) Pull out the nail allowing the ball to roll
(Gravity, Friction)
2) Ball rolls down ramp with increasing Kinetic
Energy (Gravity, Inclined Plane, Friction)
3) Ball collides with homemade ball-stopper
(Friction, Kinematics)
4) Ball-stopper pulls on string as it falls (Gravity,
Tension, Friction)
5) String pulls rock off ledge (Tension, Friction)
Steps 6-10 were completed and Week 1’s work was
assessed/repaired. A major source of failure was the original
ramp design, which was totally revamped. A persistent source of
failure was and is, however, the rock falling. In this week, a new
source of failure became apparent – the dominos.
6) Rock pulls new string in a new direction as it fell (Kinematics,
Tension, Gravity).
7) String pulls open hinged car-stopper (Tension, Friction, Gravity)
8) Car rolls down ramp (Friction, Gravity, Inclined Planes)
9) Car collides with first domino (Collisions)
10) Series of Dominos falls (Collisions, Friction)
This is where the project got interesting – the introduction of
hydraulics. Surprisingly, in this section, error is relatively low,
perhaps because of the large funnel used.
11) Dominos strike Hinged Cup filled with water (Friction, Collisions,
Hydraulics).
12) Hinged Cup swings downward (Friction, Gravity, Hydraulics)
13) Hinged Cup releases salt-water contents (Gravity, Hydraulics)
14) Salt Water pours through funnel (Gravity, Hydraulics)
15) Salt Water emerges, pours into a cup (Hydraulics, Gravity)
This section is the most error-prone in the system. The introduction of
electrochemistry/electrodynamics is likely to blame for this –
possibly because the circuitry and wiring used in this section is
not designed to pass through an electrolyte. Normal electrodes
quickly corroded in the electrolytic solution, so I made single-core
paperclip electrodes which would not corrode.
16) Electrolytic solution completes a previously made circuit
(Electrodynamics, Gravity, Hydraulics)
17) Circuit causes a motor to spin (Electrodynamics, Friction
[particularly important – any catches stop the motor])
18) Motor causes a bobbin to spin (Friction, Centripetal Forces,
Electrodynamics
19) Bobbin reels in string (Tension, Centripetal Forces, Friction)
20) String’s force direction changes and is multiplied from to a pulley
(Pulleys, Gravity, Tension)
This part is slightly error prone as well, but does have a relatively
high success rate. Particularly annoying was the fact that one
marble rarely carried sufficient force to separate the magnets, so I
ultimately used three.
21) String pulls up on needle wrapped in duct tape (Friction, Gravity,
Tension)
22) Needle releases three marbles (Friction)
23) Marbles begin rolling down plane (Friction, Gravity, Inclined
Plane)
24) Marbles collide with two magnets [hair trigger] (Collisions,
Friction, Inclined Plane, Gravity)
25) Two magnets release their grip on each other (Magnetism,
Collisions, Gravity, Friction)
By this point, the project’s creation was coming to a close. The
remaining steps have relatively high success rate, but sometimes
there are unexpected failures (as with any in a Rube Goldberg
Machine)
26) Magnets releasing allow sandbag to fall (Gravity, Magnetism,
Friction, Tension)
27) Sandbag collides with mousetrap (Friction, Springs, Collisions,
Gravity)
28) Mousetrap realigns sandbag’s course (Collisions, Springs, Friction,
Kinematics)
29) Sandbag collides with two magnets duct taped to the top of a
spring-loader (Collisions, Gravity)
30) Magnets depress loader (Collisions, Gravity, Friction, Springs)
This was the last week of step-creation. It also, unfortunately, tends to
be relatively failure-prone, particularly due to the necessity of
aiming-by-eye of the sandbag to the launcher and the need for the
“easy” button to be in the correct placement each time with
allotted rebound space.
31) Spring-loader launches fork forward (Springs, Friction)
32) Fork collides with “That was Easy” Button (Collisions, Friction, 2d
Kinematics)
33) Button relays message: “That was Easy” [No, it was not easy]
(Audio, Collisions, Friction)
Just because my creation was done did not mean I was done with the
project, however. The remainder of the weeks leading up to the
project were filled with error analysis, testing, testing, testing, and
more testing.
Scissors cutting string – It would be cool, but would have cost a lot of
string and taken a lot of time to reset
Pendulum swing – Pendulums are hard to come by
Mallet swing – the forces required to release a mallet or the forces it
would release were much higher than those I could reliably
control
Sailboat and tank of water – I did not have either the resources or time
available to undertake this section
Physics of air with a fan – Unfortunately, the forces involved were far
to small to be feasible in my machine
Turbine use – I could not get a hold of a turbine
Food use – This would get very messy
Rubber band entanglement – There was no place
for this in the machine.
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http://en.wikipedia.org/wiki/File:Rubenvent.
jpg
http://www.jimloy.com/books/goldberg.htm
http://www.biography.com/articles/RubeGoldberg-9314372