Zero Gravity Scale 1
Tri-County Regional Vocational Technical High School
Franklin, Massachusetts
Zero Gravity
Scale
HUNCH Final Report
Jacob Billington
Adam Civilinski
Lukas Hawkins
Patrick McLaughlin
Jacqueline Tedesco
Shannon Croatto
Zero Gravity Scale 2
Abstract
Gravity has given the space and matter of Earth a sense of direction and more importantly
a sense of force. The gravity of Earth provides the necessary force to contribute to the function of
scales which measure the weight of objects. Without gravity there would be no force to
counteract the normal force of the object. The mass depends on the objects force and the
acceleration; in this case the acceleration is the gravity of Earth. If the same gravity scale used on
Earth is used in a zero gravity environment such as outer space, the mass would not be able to be
calculated because the gravity of earth causes the 9.8m/s/s force. In order to measure mass in
micro and zero-gravity, our Tri-County RVTHS HUNCH team created a Zero-Gravity Scale
using centripetal forces caused by rotating force scales. Attached to the scales are the objects
being weighed; they are perpendicular to the spinning axle. The scale is created with two force
meters, both accurately measuring peak tension forces. Force meter 1 weighs the force of a
known mass while force meter 2 weighs the force of an unknown mass. Since both force meters
are on the same spinning axle the acceleration is expected to be the same. The experiment creates
its own “gravity” or acceleration by multiplying a controlled mass of object 1 and the peak
tension force collected by the force gauges. The acceleration of the object is calculated by using
F=ma. Object 2, the unknown mass, also registers a peak tension force and is divided by the
acceleration found on object 1 and the mass is determined with precision. The acceleration axle
spinning the two force meters unfortunately does not sustain a constant speed, creating a
repetitive sequence of finding the acceleration every test. To accurately determine the success of
Zero Gravity Scale 3
the Zero Gravity Scale, a series of 17 tests in Earth’s gravity environment and 17 tests in
microgravity environment using unchanged masses of both object 1 and object 2. In 1 G on Earth
the average percent error from the actual masses recorded stands as a 7.12% error, compared to a
surprising 5.46% error in 0 G. The results were not accurate enough to the actual mass values for
the Zero Gravity Scale to be subject to deployment in zero gravity enclosures such as the
International Space Station. The outcome of both 0 G and 1 G tests lead to precise calculations
with stray of one unreasonable result recorded. Nevertheless, the Zero Gravity Scale designed
and assembled by Tri-County’s HUNCH team proving the centripetal force method in a
weightless atmosphere could possibly weigh substances precisely and accurately in micro and
zero gravity.
Introduction
The United States, along with the rest of the world, has been interested with the out
reaches of space since the first satellite had orbited Earth in 1957. Advancement in aeronautical
technology and zero gravity experiments has placed robots on Mars, created an orbiting
International Space Station and landed men on the moon. With further advancements, there will
come occasions for astronauts to calculate masses similar to rocks and minerals and luckily
living organisms while being in a zero gravity environment. All scales on Earth use gravity to
measure mass, a zero gravity scale could accurately calculate using the equation F=ma and
document unknown masses in space using centripetal forces in both 0 G and 1 G atmosphere.
Gravity is a unidirectional force which has been a method to compute mass for centuries
and has given scales the basic system to function. Fishing scales, bathroom scales, and spring
scales calculate weights. Gravity is extremely important when weighing an object because it is
Zero Gravity Scale 4
the sole active function which applies force. Common house hold gravity based scales will be
useless in microgravity.
Statement of the Research Problem
Zero gravity is a complicated area of science as it is something that is not easily
reproduced for experiments. One of the most interested corporations involved in the testing of
experiments is NASA, who created HUNCH and the Reduced Gravity Program. HUNCH is a
STEM based program focused on the ideas created by high school students around the country
including students from Tri-County Regional Vocational Technical High School.
This year’s HUNCH team is comprised of six graduating seniors. Tri-County RVTHS’s
Engineering program was recommended by members of Massachusetts Institute of Technology
and was given a chance to experiment with one glove box in microgravity. Experimenting with
anything in microgravity is an extremely broad topic for scientists and engineers because very
little people have experienced the effects of micro or zero gravity. The NASA HUNCH program
has given each of the eight schools ability to research the traits of microgravity and present
experiment proposals.
Six groups of Tri-County RVTHS came up with six different projects to present to the
NASA and MIT associates for remarks, revisal, denial and appraisal. Out of the six scientific
experiment proposals only two were accepted to be an experiment aboard the micro gravity
aircraft. One of the selected experiments was a mixer, which theoretically could mix liquids,
solids, and the ultimate challenge of mixing liquids and solids in micro and zero gravity
environments. The second experiment chosen was the zero gravity scale based on a theory using
Zero Gravity Scale 5
centripetal force to measure mass in any gravitational environment especially micro and zero
gravity.
As a group of six students, everyone had a job to accomplish based upon their technical
and STEM abilities. As the HUNCH team of Tri-County, we represent strong and valuable skills
able to withstand not just the problems of academics but communal problems that need to be
overcome to become a team.
Statement of the Research Problem
Difficulty took its coarse as soon as Zero Gravity Scale was given the final ‘OK’ to start
building in the spring of 2012. Centripetal force created to find acceleration and solve for mass is
better written on paper as an idea than a drawing and a prototype. With the help from CAD
programs, an understandable virtual prototype seemed easier to comprehend and assemble than
hand sketched drawings. Our first prototype was built around the spinning axle creating the
centripetal force and framed around a triangular box. Fishing scales were the original idea for the
force meters because they were able to hold a value and the hook that held the known and
unknown masses. During the original testing trials, the arm wobbled off the meters along with
the two scales. The source of power to the axle was a wooden hand crank and a Dewalt power
drill for constant velocity. In the original 17 trials, some tests had a 4% error and others a 90%
error. The original idea was a horizontal axle spinning vertically, but we realized the unstable
objects were more difficult to read than readings scales horizontally. Eventually the fishing
scales had trouble holding and measuring values and were deemed unfit for experimentation.
The first and only prototype taught our team a lot about our project through trial and
error, along with problems to fix as the months advanced. Basic problems that came up during
Zero Gravity Scale 6
testing became vital information for the creation of the second and most recent Zero Gravity
Scale: including power sources, speed, rotational angle, and problems with the fish scales, which
all needed to be corrected.
Method
Finding any experiment to assess in zero gravity is a tremendously enormous topic; to
non-astronauts, anything could be experimented to find what occurs in zero gravity compared to
Earth’s gravity. Not every experiment is worth the time and effort to be flown on a 0 G plane
costing thousands per flyer, but every area of experimentation on Earth is worth considering as a
potential project. There is a range of sciences including biology, chemistry, electrical, medical
and mechanics that could become a basis for a strong micro gravity experiment.
As a rookie HUNCH team in the field of micro gravity, the internet and Alvar SaenzOtero, an MIT mentor with experience in zero gravity, were our primary sources of information
regarding micro gravity and past experiments.
A scale in space seems not too complicated or important to astronauts since the space
programs of Earth have been exploring the universe for years without a need for a scale. Space
programs including NASA rely on the comfort of Earth’s gravity to weigh people and objects
before they are launched into outer space. A similar idea of a scale in zero gravity is explained as
a spring diffraction scale called SLAMD created by NASA to help measure the muscle loss in
astronauts by using spring forces as the astronaut pushes his/her force on the device. This scale is
only used for astronauts, and is impossible to weigh the mass of an inanimate object with no
internal force to exert upon the SLAMD scale.
Zero Gravity Scale 7
The need for a zero gravity scale could be beneficial for space exploration if it reaches far
enough to be unable to rely on Earth’s gravity. Minerals, organisms, and foreign elements in
space cannot be weighed with common household scales because the acceleration due to gravity
on Earth is eliminated by the zero gravity environment; it is only logical to create your own
acceleration in place of acceleration due to gravity.
The mathematical setup of the scale is equally if not more important than the mechanical
setup of a zero gravity scale. The concrete foundation formula to calculate the mass of an object
is force = mass x acceleration, any object is able to be weighed with or without gravity.
The source of acceleration is a bound axle attached to a 12 volt CIM drive motor which is
anonymously controlled by one Texas Instruments jaguar motor controller. A motor testing
controller connected to the jaguar motor controller is synchronized manually. The experiment is
powered by a 12 volt lead acid battery and regulated by a fuse box with a 30 amp fuse. In the
emergency of a malfunction of any kind a red main circuit kill switch is added.
Two force gauges are reported in the Zero Gravity Scale mounted horizontally at a
perpendicular angle to the axle so each scale is facing opposite directions. Donated by Mark-10
are the two Series 7 force gauges, which measure at 5in x 2in x 1in in size, used to deliver
measurements in extremely accurate forms, displaying Newton’s, grams, and pounds on its vivid
digital screen. The force gauges are important to our experiment because they are able to record
peak tension, which holds the highest tension value until cleared or stored manually. The stored
data entries are able to be uploaded manually by USB capability onto a spreadsheet format.
Force gauge 1 is the control meter which is given a known mass to calculate the acceleration due
to the calculated force of the spinning axle using F=ma. Force gauge 2 contains an unknown
Zero Gravity Scale 8
mass calculated by the force registered on the gauge after the axle spins multiple times for 2-3
seconds, and the acceleration found by force gauge 1 is the same because both force meters are
on the same axle.
The frame of the scale is a 20in x 20in x 20in cube assembled with 1in x 1in tslotted 80/20 framing, held firmly together with a quantity of four bolt elbow brackets. Separated
by bars of t-slots, the electrical components, except the force meters, are tightened firmly at the
bottom of the scale. To prevent any possible injury to hands, the rotating force meters are
shielded by Lexan glass and can be only accessed by one port hole in the glove box.
The original goal of our micro gravity experiment was to acquire the knowledge of the
controlled mass on force gauge 1, our team will be able to calculate the unknown mass on force
gauge 2 implementing the formula Mass=F/a using the spinning motion of centripetal force in
micro gravity.
The Method that had been stated in advance has been impacted by the guidelines of the
flight and the glove box restrictions. The HUNCH teams were able to choose between a
horizontal and a vertical glove box cautioning a weight limit of 50 pounds, which included the
mounting plate that connects the projects to the glove boxes. The vertical glove box seemed too
tall for our scale’s dimensions, which can cause too many problems during our live experiment
that are time expensive to repair. The horizontal position of the box posed a convenience for the
flyers and the scale that is spinning horizontally. The port holes of the box are measured and
enable the buttons and force gauges to be positioned comfortably enough to reach and to be read
when recording data. There is no way the flyers could prepare for the micro gravity flight but a
few mechanical precautions were made prior to fight week. Every person flying is educated
Zero Gravity Scale 9
about the Zero Gravity Scale’s mechanics, electronics, and the force gauges in case one flyer was
unable to experiment on the project and another needed their place. Before both flights, all
settings were programmed properly for quick testing on the first few parabolas for maximum
capability, functionality and efficiency.
The 1 hour and 45 minute Zero-G plane experience is separated into 32 parabolic
maneuvers; 30 parabolas create 15-20 seconds of little to no gravity and the last two parabolas
recreate lunar and mars gravity. When experimenting with the Zero Gravity Scale, our order of
operations were first to rotate the axle for 4 seconds, read the force data off of the control for the
back-up data transcriber which took about 5-8 seconds, load the readings into the Mark-10 Series
7 force gauges and finally zero the force gauges which was about 5 seconds. The sequence takes
about 14 –18 seconds in total. While the 1 G test recorded 17 trials, the reduced gravity program
allowed flyers to experiment with 30 parabolas, meaning 30 different opportunities to
experiment which gave us more than enough data. We were able to immediately begin
experimenting with the scale when hyper-gravity transferred into 0 G, to gain as much time to
receive accurate and precise data without panic.
Results
Ground Test #1
Flight 2
Scale A Scale B Actual A
2.004
2.011
0.165
1.954
1.951
0.165
1.985
2.01
0.165
Percent
Actual B Calculated B Error
0.18 0.165576347
8.01%
0.18 0.164746673
8.47%
0.18 0.167078086
7.18%
Zero Gravity Scale 10
1.98
2.005
1.98
2.05
1.975
2.005
1.985
2.04
2.015
2.03
1.99
2.045
1.965
2.005
2.01
1.985
2.001
1.98
2.012
2.035
2.01
2.024
2.02
2.06
2
2.005
1.965
2.055
Average Percent Error
0.165
0.165
0.165
0.165
0.165
0.165
0.165
0.165
0.165
0.165
0.165
0.165
0.165
0.165
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.18
0.167083333
0.170833333
0.167506329
0.169571788
0.166228288
0.169560302
0.168358779
0.162947761
0.163268366
0.166886183
0.166149254
0.168267327
0.1654125
0.172557252
7.18%
5.09%
6.94%
5.79%
7.65%
5.80%
6.47%
9.47%
9.30%
7.29%
7.69%
6.52%
8.10%
4.13%
7.12%
The ground test was simulated as a preparation for the micro gravity experiment. The
force gauges were not changed out except for the data recording. As recorded in the ground test,
the results were between 4.13% and 9.47% error, with an average of 7.12% error. Even though
the scale did not accurately measure mass using centripetal force in micro gravity, the final result
suggested a precise measurement of mass. The ground experiment may have sustained some
mechanical faults but preformed with solid results, and human error was also a factor to be
considered.
Flight Test #1
Test was inconclusive. Throughout the entire first flight test in the micro gravity plane, the
settings on the Mark 10 force meters was calculating peak compression instead of peak tension,
which reads the outwards force instead of the inwards force. Because this was the first test, there
were no problems to fix in preparation for the second flight. This error was due to the fact that
Zero Gravity Scale 11
we did not have one of our own students on our first test flight, therefore the flyers working on
our project did not know to change it to peak tension.
Flight Test #2
Flight 2
Scale A Scale B Actual A Actual B
2.005
2.01
0.165
0.18
1.955
1.95
0.165
0.18
1.985
2.1
0.165
0.18
1.97
2.125
0.165
0.18
1.98
2.045
0.165
0.18
1.945
2.145
0.165
0.18
1.985
2.04
0.165
0.18
2.005
2.03
0.165
0.18
1.99
2.035
0.165
0.18
1.925
2.145
0.165
0.18
2.01
1.9
0.165
0.18
2
1.98
0.165
0.18
2.01
2.035
0.165
0.18
2.01
2.035
0.165
0.18
2
2.06
0.165
0.18
1.965
2.055
0.165
0.18
1.965
2.055
0.165
0.18
Average Percent Error
Percent
Calculated B Error
0.165411471
8.10%
0.164578005
8.57%
0.174559194
3.02%
0.177982234
1.12%
0.170416667
5.32%
0.181966581
-1.09%
0.169571788
5.79%
0.167057357
7.19%
0.168731156
6.26%
0.183857143
-2.14%
0.155970149
13.35%
0.16335
9.25%
0.167052239
7.19%
0.167052239
7.19%
0.16995
5.58%
0.172557252
4.13%
0.172557252
4.13%
5.47%
During the second flight, the results recorded an average of a 5.47% error. The percent
error was relatively small, so we concluded that it was due to human interference. The error in
our final flight can be suggested as mechanical default, the wobble of the plane as it flew, and the
handling of the machine throughout the experiment. Except for a spike in results at 13.35% error,
the final test on the micro gravity flight proves the hypothesis created by centripetal forces.
Human error or plane vibration could be the cause of the unusual result.
Zero Gravity Scale 12
Hyper-gravity
Result inconclusive. There was no testing involving hyper-gravity in either of the two
flights.
Discussion
When developing an experiment, there are always challenges that must be overcome; and
these challenges usually lead to success. Our project posed many problems; in the beginning, it
was the simple concept of weighing objects using centripetal force. Our teams brainstormed for
about a month and were able to develop a design that proves our concept. This design would
consist of a triangular frame that would be orientated so that the arms would be spinning in a
vertical plane. This is where one of greatest challenges first appeared. In our proof of concept
design, we used simple fishing scales, but these particular scales would only hold their values if
there was a constant force for two seconds. It was near impossible to keep constant force for two
seconds when the original design was in a vertical orientation. This was due to the fact that when
spinning in a vertical orientation, gravity would make the values fluctuate drastically when
operating. This would not be a problem in a reduced gravity environment, but we were looking
for a simple proof of concept. In the final preparations before the micro gravity flight in Houston,
our lead acid battery created an unexpected problem with weight figuring out a way to mount it.
The battery’s 14 pounds exceeded our weight limit by 10, which was a huge issue. There was no
other battery and no time to rewire the electrical system, which requires dismantling the entire
project. Luckily, for our Tri-County’s HUNCH team the experiment was given the stamp of
Zero Gravity Scale 13
approval to fly even with an overweight experiment; it was considered safe to fly by the engineer
of the glove boxes.
Without drive to create a successful experiment and a passion for what you are doing,
there is no reason to be a part of the NASA HUNCH program. Since the very first day of
HUNCH there have been hard times, failures, anger and worst of all regret. Tri-County HUNCH
looks back at the past 2 years with gratitude because we got to work side by side with NASA
engineers and fellow high school students around the country. We were given the opportunity to
experience micro gravity for the very first time, and we felt triumphant when we reached our
ultimate goal. The six students on the team had many differences but all had the same goal to
create a working Zero Gravity Scale which was successfully tested aboard the Zero-Gravity
plane.
Conclusion
In the conclusion of our project, we learned centripetal forces can find acceleration and
calculate mass in micro and zero gravity. Since the entire project was secure with no free moving
parts, the zero gravity did not affect the way the experiment performed. The results the team
recorded in regular 1 G and the 0 G were generally the same. The similar results of 1 G and 0 G
reassures the physics using m=F/a; mass can be solved the same in different accelerations due to
gravity and forces due to acceleration. There are some mechanical problems which could
defiantly improve the accuracy of the scale.
The reason to have two force gauges to calculate mass was to find the acceleration. The
acceleration of the CIM motor that was used to power the rotating axle could not be determined.
If the acceleration of the axle using centripetal force was determined based upon angular
Zero Gravity Scale 14
acceleration formula, there would be no need for a second force gauge if the acceleration is a
known factor. When the axle accelerates it generates peak tension recorded by the Mark-10
Series 7 force gauge.
As part of the HUNCH program, school teachers around the country contribute items to
the HUNCH teams like Tri-County’s; this is called the outreach program. They are curious to see
what is going to happen in micro gravity or hyper gravity to these specific objects. The TriCounty HUNCH team partnered with Fairport School and filmed how a magnetic tower and a
Newton thermometer act in a weightless environment. The Hunch teams on the Zero-Gravity
plane were able to experiment with their own outreach items during 2 parabolas. Some items
acted inversely than others like how a stack of magnets are evenly separated in micro-gravity,
and how air glider glide without falling, and tops keep spinning until acted upon by an external
force.
As the universe is explored and studied, the scales that Earth depends on for measuring
mass are useless anywhere else. Anything that is sent into space, whether it is a satellite or a
human being, is weighed before flight. If we are every able to land on another planet, it is highly
unlikely that their gravity will be equal to that of Earth’s. The Zero Gravity Scale uses centripetal
force to find acceleration and is able to find any mass in any atmosphere. Hopefully in the near
future when planets, asteroids, and other objects in space are discovered, a zero gravity scale
would be helpful to calculate what an unknown substance weighs within minutes.
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Works Cited
"Centripetal Force." Centripetal Force. N.p., n.d. Web. 31 May 2013.
"If You've Ever Dreamed of Flying, You Can.It's Surprisingly Simple â but No Less Profound."
Zero G Corporation. N.p., n.d. Web. 31 May 2013.
"Inside a Bathroom Scale." HowStuffWorks. N.p., n.d. Web. 31 May 2013.
"Motion - Force and Acceleration (F=ma)." Motion - Force and Acceleration (F=ma). N.p., n.d.
Web. 31 May 2013.
"NASA - National Aeronautics and Space Administration." NASA. N.p., n.d. Web. 31 May 2013.
"Newton's Three Laws of Motion." Newton's Three Laws of Motion. N.p., n.d. Web. 31 May
2013.
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Acknowledgements
Reduced Gravity Program-Creating fantastic opportunities for high school with an incredible
desire in STEM
Go Zero–G Corporation- Lending the Zero-G plane and your week for our HUNCH experiments
Florence Gold- There would be no Tri-County HUNCH program without your support and
consideration to all high school kids
Michael Garland- Being our mentor while in Houston
Mohammad Bakr-The original spark of Tri-County HUNCH
NASA-Creating an incredible HUNCH student program, allowing a once in a life time
opportunity experience
Alvar Saenz-Otero-Excellent mentor from MIT who used his past familiarities in micro gravity
to help our team understand the HUNCH program
Mark-10- for their generosity on donating two Series 7 force gauges which was the sole
dependable device on the Zero-Gravity Scale. Thank You
Jean George-Supporting our team through the past two years
Tri-County-gave the HUNCH team the privilege to travel to Houston with zero expenses.
Billings Central Catholic High School, Billings, MT- helping our HUNCH team with a
cooperative flying crew, there would be no results without your help.