Rube Goldberg Project:Lab Report

By: Sagar Patel, Zack Audy, Phillip Bagley, and Ryan LenhardtBartlett High School Academy

Bartlett High School 3-18-11

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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.

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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

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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

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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

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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:

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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

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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

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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 Trial 2 Trial 3 Trial 4 Trial 5

Worked X X X X X

Didn’t

Work

Water bottle falls into funnel properlyTrial 1 Trial 2 Trial 3 Trial 4 Trial 5

Worked X X X X X

Didn’t

Work

Waterwheel pulls hammer down

Trial 1 Trial 2 Trial 3 Trial 4 Trial 5

Worked X X X X X

Didn’t

Work

Hammer hits car

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Trial 1 Trial 2 Trial 3 Trial 4 Trial 5

Worked X X X X X

Didn’t

Work

Car travels meter without interruption

Trial 1 Trial 2 Trial 3 Trial 4 Trial 5

Worked X X X X X

Didn’t

Work

Total machine run throughTrial 1 Trial 2 Trial 3 Trial 4 Trial 5

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.

Time Trials:

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Time it takes

for…

Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Average

Bag to inflate 1.04

seconds

1.39

seconds

1.04

seconds

1.32

seconds

1.32

seconds

1.22

seconds

Waterwheel to

pull hammer

3.00

seconds

2.87

seconds

3.02

seconds

2.88

seconds

2.94

seconds

2.94

seconds

Hammer hits

car

.92

seconds

.99

seconds

.93

seconds

.91

seconds

.95

seconds

.94

seconds

Car travels

meter with

spring

.31

seconds

.27

seconds

.4 seconds .25

seconds

.37

seconds

.32

seconds

Car travels

meter without

spring

.37

seconds

.31

seconds

.48

seconds

.27

seconds

.47

seconds

.42

seconds

Complete run

through

4.96

seconds

5.02

seconds

5.40

seconds

4.33

seconds

4.50

seconds

4.84

seconds

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

Wind

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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

Hammer

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Formula= ½ (I) 𝑤2

I= 1/3m𝐿2

M=.195 kg

L=.9906 m

W= 𝐷/𝑡=πt

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%

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