Rube Goldberg Project:
Lab Report
By: Sagar Patel, Zack Audy, Phillip Bagley, and Ryan Lenhardt
Bartlett High School Academy
Bartlett High School
3-18-11
1
Abstract:
The goal of this project was to understand energy transformation and be able to
apply calculations. Also it involved technical skills, such as building structures and also
testing the creativity of the students due to the constraints on only recyclable materials
may be used. The first part of the project was to make a machine with a minimum of 4
energy transformation that has the ability to move a car one meter, or 3 feet, without
physically touching the car. The second part of the project was to find the efficiency of
each energy transformation and from there conclude it with the overall efficiency of the
machine. The group learned about different topics such as the relationship between the
overall efficiency of the object and the types of materials used. The goal is to learn about
energy and the different types of energy transformation, we also want to analyze the
efficiency for each transformation. Another goal is to use the skills acquired in physics to
apply formulas to find the efficiency of each operation. One of the target goals that were
accomplished was to identify the strengths and weaknesses in a model. We had to find
the efficiency of each object and we knew that a higher efficiency means that a small
amount of energy is actually lost. Also another target goal covered was compare and
contrast data from a complex data presentation (1a). We were able to obtain the data and
calculate efficiency for each transformation. This helped compare the efficiency of
different parts of the machine. Another target goal that was covered was goal which was
identifying a simple mathematical relationship between data (1e). We felt this was an
important goal because part of the project is to interpret our data that we got from our
machine.
2
Table of Contents:
Section
Page Number
Introduction…………………………………………………………….pg 4
Background………………………………………………………….…pg 4-7
Materials……………………………………………………………….pg 7
Recyclable………………………………………………………pg 7
Non-Recyclable…………………………………………………pg 7
Procedure……………………………………………………………....pg
Results…………………………………………………………………pg
Conclusion…………………………………………………………….pg
Appendix……………………………………………………………...pg
Trials………………………………………………………………pg
Time Trials…………………………………………………….pg
3
Introduction:
The recyclable Rube Goldberg machine was the quarter long project and required
everyone to engage in deeper thinking. The purpose of this project was to better
understand energy and to think creatively to solve problems. Another purpose of the
project was to work in a group cohesively and improve group/people skills. There were
many things learned about energy transformations and how to follow the various types of
energy throughout the machine. Some examples of what we learned include; how to
calculate efficiency in each operation of our machine, how to use materials to the best of
our abilities, and also how to calculate water, wind, and rotational energy. Overall, this
project was very beneficial and we learned a lot.
Background:
A Rube Goldberg machine is a deliberately over-engineered machine that
performs a very simple task in a very complex fashion, usually including a chain reaction.
The expression is named after American cartoonist and inventor Rube Goldberg. We had
to have a minimum of 4 energy transformations. Some examples of this would be
potential, kinetic, rotational, heat, and wind energy. The definition of a energy
transformation is the capacity to produce changes within a system. We also had to find
the efficiency for each energy transformation and the formula for that is Work Out
divided by Work In. The group understood the concept that the overall efficiency of the
machine will be low due to the fact that the materials used were recyclable. We did a lot
of research on this project before we actually started to sketch. The initial plan was to
have 6 energy transformations, including wind energy. However, we knew that it would
be difficult to find the efficiency of the fan that supplied the wind. The team also realized
that a bag could be taped on the fan, which will inflate and tip over the water in the water
bottle in the water wheel. We also had an electrical source of 9V, which allowed us to use
the fan. From that moment we researched the formula for wind energy and it was
(d)(D2)(V3)(C). In this formula “d” represents the density of the air and D represents the
diameter of the fan blades. In addition to this, the V is the velocity that the wind is
moving and C represents a constant, which is 0.005. The formula for work is FxD when F
4
is equal to force and D is equal to distance, it is measured in joules. Some of the prior
background research we did was we saw the different types of ideas on YouTube. Some
of the machines used a fan on the top of the ceiling and many of the machines used Lego
toys. Also most of them had some type of ramp. There was one design which was
creative because they used a milk carton as a pulley system; they also used cereal boxes
to heighten the structures. These videos helped us realize that we wanted to do something
unique, which none of the videos we watched had. The goal was to create a water wheel
to have hydro energy; the problem statement stated that we had a gallon of water to work
with. We knew about water wheels by prior knowledge and we did some research on it to
generate the type of materials we should use. A water wheel is a machine used to
converting the energy of falling water into useful forms of water. The idea was that the
force of water would pull the string, which would trigger the hammer. The hammer then
would hit the car and push it a meter. We knew that the car had to go 1 meter and we
decided to be on the safe side by putting sand in one of the cans, which we used during
the testing process. The initial predication was that it will make the car go faster.
However, we realized that the car was jumping up of the ground due to the strong force
and was smacking into objects in the machine, which was against the constraints. We
knew that we could not touch or affect the car in any way in the meter, so we decided to
take some sand out and to position the car in an angle to prevent it from hitting the pop
cans we used as supports. In geometry we learned about angles and we realized the
hammer is hitting the side of the car. Thus, when the car is on an angle the car will not hit
any obstacles and have a faster velocity.
Another part of the project we researched as what the base should be made out of.
The answer we came up with was cardboard. The positive effects of this are that
cardboard is a recyclable material and can be easily glued together by using a hot glue
gun. However, the problem was the design we constructed implemented a water wheel,
which obviously has water. We knew that after many trials the cardboard would become
vulnerable and would collapse the entire structure. Cardboard takes a while to actually
have water damage. So if the water spillage from the water wheel is cleaned up quickly
there would be no damage to the structure. We had to do some research on the durable
cardboard compared to the other types of cardboard. From there we had the thick
5
cardboard on the bottle of the top base and had the light cardboard (cereal boxes) on the
top of the base. We did this because it was the only way the structure would stay stable.
Also it makes sense to put a lesser weigh piece of cardboard in a higher weight piece of
cardboard. Also another thing we researched as on how to make a durable structure out of
recyclable materials. The best solution we found to this was to use soda cans and hot glue
them on top of each other. This would provide a steady structure, which would not easily
fall down. The group was also thinking about rotational energy because this occurred
when the fan was turned on. However, the fan we used required us to break the fan to
actually find the efficiency, which we did not. Thus, we even looked up the formula for
rotational energy and it was KER=½(I)(ω2). In this formula, there were two aspects we
didn’t understand. The first was “I”, which stands for moment and after some research we
found that the formula for it is I=1/3mL2 when “m” is mass and “L” is length/distance
traveled. The second aspect of the KER formula was the “ω”, which stands for omega,
the formula for this is d/t when “d” is distance and “t” is time. The potential energy
formula is mass*gravity (9.8)*height. We used this formula to find the water
calculations.
The group regretted not using additional forms of energy, so we came up with
spring energy. The prior knowledge we had from physic we knew that a spring can be
either stressed or compressed. We put the spring behind the car to hopefully increase the
velocity of the car. The formula for spring energy is 1/2kx2, when “k” is the squish
distance and “x” is the force acting upon the spring. We also encountered another
problem, the water bottle was first placed vertically and when the bag inflated to tip the
bottle the water would never land in the water wheel. Thus, we began to look at the
bigger picture and apply what we knew about vertical and horizontal direction. We
placed the bottle in a horizontal position. Therefore, the water fell into the funnel which
then poured onto the water wheel which solved our problem. Also the hammer had such a
string force that it would sometimes hit the top part or other cans on the machine. We
knew that the cans would become dented so we placed cardboard as a substitute of a
protective barrier and works fairly well. We researched how to keep something steady
and in place like a swinging hammer. We placed a metal rod and cut pieces of a straw
and put them on both sides so the hammer would go in the same direction every single
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time. This greatly increased the chances of the machine making the car move the required
meter.
Materials:
Recyclable:

Cardboard

Chipboard

Pop cans

Orbits gum container

Applesauce cups

String

Plastic bag

2-liter bottle

Water bottle

Soup can

Gallons of milk

Mini pop cans

Finish dishwasher tablets container
Non-Recyclable:

Fan

Metal rod
Procedure:
7
Results:
-Picture of the whole machine (well most of it).
Conclusion:
Our objective, in the end, was successful and worked nearly every time. However,
it was no walk in the park to get the machine that way. Along the path of accomplishing
our goal of getting the car to move the meter, we came across many setbacks. The major
setback was after we finished building the main structure of our building, a freshman who
was playing a videogame in the tech lab negligently backed up onto or project and fell on
it; crushing our entire structure. We corrected this setback by spending a lot of time at
Zack’s house, there were 4 visits, each lasting approximately 4 to 5 hours. One of the
main factors for our groups’ success has to be given to hot glue. This was very useful to
our group because our design needed layers of cardboard to give the structure more
8
support and we were able to hot glue places that couldn’t be reached by a stapler, plus it
gave the cardboard a better bond compared to the staples.
Another contribution to our success was some of Phil’s incredibly creative ideas.
Some of his ideas include; building the waterwheel, the hammer, and the spring on the
car. For the waterwheel, Phil ingeniously hot glued several applesauce containers around
an Orbits gum container. We used the applesauce containers because we learn in our POE
class that cup shaped fans produce more energy when the water hits them rather than a
flat surface. This is because energy is pushed straight up after the water hits the cups,
compared to a flat surface were the water just slides off. For the hammer, we needed long
tubing that would act as the shaft of our hammer, but we didn’t know how to make a
recyclable one. So Phil cut off the tops of four water bottles and then hot glued them
together, forming a water bottle cylinder. Phil’s final idea was to put the spring on the car
rather than the top of our structure. Our original idea was to put the spring on the top and
our hammer would swing over, hit the spring, then go in the opposite direction and hit
our car. However, after many tests, we realized that our idea would not work, and we
didn’t know how to incorporate spring energy into our design. Phil put the spring on the
back of our car to give the car an extra speed boost when it is hit by the hammer. Data
actually showed that the car traveled .1 second faster on average when we added the
spring.
There are many improvements that could have been applied to our machine to
make it more overall efficient. Some of the improvements include; a bigger height to our
machine, an increase in the hammers weight, more stable supports and less water in the
bottle that spilled over. A bigger height to our machine would have given us more room
to increase the number of water bottle halves to our hammers shaft. Also, we would have
been able to increase the distance the water travels. Both of these increases would have
overall increased the potential energy of the machine, this is because the formula is
PE=mgh. Increasing the hammers weight would have also increased the kinetic energy
caused by the hammer. If our group had found a way to make more stable supports for
our structure, we wouldn’t have had to spend as much time fixing them after they broke
from the weight of the fan. We could have spent this extra time focusing on more useful
tasks, such as data collection. We should have used less water because every time the
9
water went down the waterwheel, the water spilled out and splashed the cardboard. After
many splashes, the cardboard started to get soaked and become less stable. Therefore, if
we used less water, we could have delayed this occurrence. These were the only changes
that our group would have conducted if we could do it over again.
We feel that this project, besides the few changes that are stated above, does not
have much potential to go any further. We feel that we completed this Rube Goldberg
machine to our best abilities don’t feel that it has much of a future.
Our final results were very close to what we original hoped for them to be, with
one exception. This one exception is that we originally had the spring placed on the top
of our structure, not on the car. But as it turns out, the spring on the car actually increased
the end result of our project. We have this conclusion supported by data in the sense that
with the spring on the car, the average speed was .32 seconds. The average speed it took
the car to travel the meter without the spring was .42 seconds, proving that the change
was a good idea. There was another small change we made in our machine, and it had to
do with the placement of the water bottle when the fan pushed the bottle over. Our
original thought was to have the water bottle in a vertical position, and when the bag
expanded, it would push the bottle completely 180°. However, on the day of the test, the
water bottle wasn’t falling into our funnel very accurately, so we came up with the idea to
lay the water bottle down parallel to the top of the structure. This method was more
accurate and quicker because it only moved 90° rather than the 180° like before.
To sum it up, our group learned a lot about energy and each other. We learned
how hard it is to stay on task and split up the work evenly among the group. On an
academic stand point, we all gained knowledge about following different types of energy
as they go through different transformations. We learned that energy is neither created or
destroyed, just transferred. In addition to this we learned how to calculate efficiency and
have become even more comfortable with the formulas to calculate potential energy and
kinetic energy, as well as a couple new formulas such as wind, water, and rotational.
Learning all of these things, we feel, was the goal of this project and we think that the
goal has been accomplished. In conclusion, this project was beneficial to us in more than
ways then we ever thought it would.
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Appendix:
Trials of machine:
Fan pushes water bottle over
Trial 1
Worked
Trial 2
Trial 3
Trial 4
Trial 5
X
X
X
X
Water bottle falls into funnel properly
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
X
Didn’t
Work
Worked
X
X
X
X
X
Didn’t
Work
Waterwheel pulls hammer down
Trial 1
Worked
X
Trial 2
Trial 3
Trial 4
Trial 5
X
X
X
X
Didn’t
Work
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Hammer hits car
Trial 1
Worked
X
Trial 2
Trial 3
Trial 4
Trial 5
X
X
X
X
Didn’t
Work
Car travels meter without interruption
Trial 1
Worked
X
Trial 2
Trial 3
Trial 4
Trial 5
X
X
X
X
Total machine run through
Trial 2
Trial 3
Trial 4
Trial 5
Didn’t
Work
Trial 1
Worked
X
X
X
X
X
Didn’t
Work
Our machine worked 100% of the time during testing at Zack’s house after it was
completed. Many more tests were performed; however, only five were recorded.
Unfortunately when it came down to the final test in front of Mrs. Brandner, the hammer
got caught on a small piece of hot glue that was sticking out in its path. After a quick trim
of the glue, the machine was set back up and on the second try, worked perfectly.
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Time Trials:
Time it takes
Trial 1
Trial 2
Trial 3
Trial 4
Trial 5
Average
1.04
1.39
1.04
1.32
1.32
1.22
seconds
seconds
seconds
seconds
seconds
seconds
Waterwheel to
3.00
2.87
3.02
2.88
2.94
2.94
pull hammer
seconds
seconds
seconds
seconds
seconds
seconds
.92
.99
.93
.91
.95
.94
seconds
seconds
seconds
seconds
seconds
seconds
Car travels
.31
.27
.4 seconds
.25
.37
.32
meter with
seconds
seconds
seconds
seconds
seconds
Car travels
.37
.31
.48
.27
.47
.42
meter without
seconds
seconds
seconds
seconds
seconds
seconds
Complete run
4.96
5.02
5.40
4.33
4.50
4.84
through
seconds
seconds
seconds
seconds
seconds
seconds
for…
Bag to inflate
Hammer hits
car
spring
spring
Electrical to Wind:
Electrical
120 V
.54 A
Joule’s Law: P=I*V
P= .54*120= 64.8W
E=Pt
E=64.8(10) = 648 Joules
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Wind
Wind formula- (d)(𝐷2)(𝑉3)(C)
Density of air=0.00012041
Turbine diameter= .0762
Velocity= 2.4
Constant=.005
(0.0012041)(.07622) (2.43)(.005)=
.000483 J
Wind to Potential:
Water Bottle
Formula= mgh
M= .105 Kg
H= 7 in or .1778 m
(.105)(9.8)(.1778)= .183 J
Hammer
Formula- mgh
M= .195 Kg
H= .9906 m
(.195)(9.8)(.9906)= 1.893 J
Potential to Kinetic:
Water Bottle
Kinetic = ½ mv2
M=.105 Kg
V=.1778/.94= .189 m/s
K=.5(.105)(.1892)= .002 J
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Hammer
Formula= ½ (I) 𝑤2
I= 1/3m𝐿2
M=.195 kg
L=.9906 m
𝜋
W= 𝐷/𝑡= 𝑡
t=.94 sec
½ (.064) (3.342)
𝐾𝐸R= .357 J
Kinetic to Water:
Water
Water formula= mgh
M=.09 Kg
7 inches or .1778 m
(.09)(9.8)(.1778)=
0.157 J
Water to Spring:
Spring
Spring formula = ½ kx2
X= .357 N/m
K= 0.00635 m
½(.00635)(.357)2=
0.0004067 J
Total Efficiency:
Total Energy In: 648 Joules
Total Energy Out: 0.0004067 Joules
0.0004067 /648 = 0.0000006245 J x 100%= 0.00006245%
15
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