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General Information
Years in SO 4
Current Team Portola High School
Grade 11th
Past Team(s) Jeffrey Trail Middle School
State SoCal
Division C
Total medals 45
  • 28 invitational medals
  • 11 regional medals
  • 5 state medals
  • 1 national medal
Competitor Info
Competitions attended 20
  • 15 invitationals
  • 4 regionals
  • 3 states
  • 1 national
Social Media
Discord andrewzian#0482

Mrgreencacti competes on the Portola High School Science Olympiad team. He also writes tests and volunteers to proctor at certain tournaments and competitions, as he has done throughout all of his years doing Science Olympiad.

Mrgreencacti was a student at Jeffrey Trail Middle School in the 2016-2017 and 2017-2018 years. He joined Science Olympiad in his 8th-grade year (2017-2018) and was on the "Blue Team," or competition team for all competitions. He was part of the first generation of students at Jeffrey Trail to win first place in the Southern California State Tournament and advance to the National Tournament, where Jeffrey Trail placed ninth.

In the 2018-2019 year, he tried out and got onto the Portola High School Science Olympiad team as a freshman along with a lot of his other Jeffrey Trail peers. From there, he was chosen to be on the main competition team (the "A Team" or "Team A") for every competition in the 2018-2019, 2019-2020, and 2020-2021 school years.

In June 2020, the summer leading up to his junior year, Mrgreencacti was chosen through election and interview processes to become one of two captains for the Portola SciOly team. In April 2021, Mrgreencacti was reelected captain and is looking forward to a great season to come.

JT Socal
Jeffrey Trail wins first place in Southern California in 2018.
PHS Team
Mrgreencacti poses with the rest of the Portola Science Olympians at the start of the 2018-19 season.
PHS Reg 2020
Portola SciOly at the 2020 OC Regional competition. Both A Team and B Team are present.


8th Grade - 2017-2018

Event Kraemer Scrimmage Ladera Vista Mesa Robles Kraemer Regionals State Nationals
Battery Buggy - - - 3rd 1st 9th 23rd
Hovercraft 5th 2nd 3rd 3rd 4th 10th 7th
Thermodynamics 2nd 14th 3rd 5th 1st 2nd 3rd

11 medals total

9th Grade - 2018-2019

Event Portola Scrimmage Mesa-Wilson Polytechnic Regionals State
Circuit Lab 1st 3rd 3rd 5th 10th
Fermi Questions 1st 3rd 4th 14th 3rd
Thermodynamics 1st 15th 1st 3rd 5th

9 medals total

10th Grade - 2019-2020

Event SOLVI Polytechnic Regionals State1
Circuit Lab 8th 1st 17th -
Machines 11th 1st 5th -
Sounds of Music 1st 1st 4th -

1: canceled due to COVID-19

6 medals total

11th Grade - 2020-2021

Event BEARSO Rickards Mira Loma Duke SOAPS GGSO Regionals BirdSO State
Chemistry Lab 24th 35th _ 25th _ 27th 4th 22nd 12th
Circuit Lab 85th _ 8th 16th 11th 24th 1st 13th 17th
Machines 77th 5th 13th 3rd 5th 25th 1st 5th 2nd
Sounds of Music 7th 5th 4th 4th 9th 8th 3rd 1st 4th
WiFi Lab 1 _ _ 2nd 2nd _ _ _ _ _
Fermi Questions 1 _ _ _ 9th 9th _ _ 22nd _

1: trial event

19 medals total

Event List

Comprehensive event list:

  • Battery Buggy B
  • Circuit Lab C
  • Chemistry Lab C
  • Dynamic Planet B
  • Experimental Design B
  • Experimental Design C
  • Fermi Questions C
  • Hovercraft B
  • Solar System B
  • Thermodynamics B
  • Thermodynamics C
  • Machines C
  • Science Quiz Bowl C
  • Sounds of Music C
  • WiFi Lab C
  • Wright Stuff C

2017-2018 (8th grade, Div B)

Main events:

Not competed events:

Filler events:

2018-2019 (9th grade, Div C)

Main events:

Filler events:

2019-2020 (10th grade, Div C)

Main events:

Not competed events:

2020-2021 (11th grade, Div C)

Main events:

Trial events:

Team Performance History

1st Jeffrey Trail Middle School received a 1st place trophy at the 2018 Ladera Vista Invitational Tournament.
3rd Jeffrey Trail Middle School received a 3rd place trophy at the 2018 Mesa Robles Invitational Tournament.
1st Jeffrey Trail Middle School received a 1st place trophy at the 2018 Kraemer Invitational Tournament.
2nd Jeffrey Trail Middle School received a 2nd place trophy at the 2018 Orange County Regional Tournament.
1st Jeffrey Trail Middle School received a 1st place trophy at the 2018 Southern California State Tournament.
9th Jeffrey Trail Middle School received a 9th place trophy at the 2018 National Tournament.
3rd Portola High School received a 3rd place trophy at the 2019 Polytechnic Invitational Tournament.
4th Portola High School received a 4th place trophy at the 2019 Orange County Regional Tournament.
1st Portola High School received a 1st place trophy at the 2020 Polytechnic Invitational Tournament.
5th Portola High School received a 5th place trophy at the 2020 Orange County Regional Tournament.
18th Portola High School received a 18th place trophy at the 2020 BEARSO Invitational Tournament.
2nd Portola High School received a 2nd place trophy at the 2020 Rickards Invitational Tournament.
15th Portola High School received a 15th place trophy at the 2021 Mira Loma Invitational Tournament.
7th Portola High School received a 7th place trophy at the 2021 Duke University Invitational Tournament.
7th Portola High School received a 7th place trophy at the 2021 Science Olympiad at Penn State Invitational Tournament.
21th Portola High School received a 21th place trophy at the 2021 Golden Gate Invitational Tournament.
4th Portola High School received a 4th place trophy at the 2021 Orange County Regional Tournament.
5th Portola High School received a 5th place trophy at the 2021 Southern California State Tournament.

Event Description and Experience

This section goes over the experience that Mrgreencacti had in each of his main events, from his own 1st person point of view.


I was in Hovercraft in 8th grade. I chose hovercraft mostly because the name sounded cool to him at the time. I started off learning the basics of what was on the rules and was taught by a certain unnamed mentor kinematics and collisions. This was my first exposure to physics. Around the same time, a hovercraft demonstration was done by a more experienced Science Olympian. At the time, I mostly thought that it was loud.

Having been second best in weekly testing for the study portion of the event, I was chosen to be on the blue team for Hovercraft. I continued to study the mechanical physics involved with the event, writing numerous practice tests and compiling the team's binder. I also spent many hours afterschool with my partner (who actually built the hovercrafts), testing, mainly for balance, arranging the penny stacks and nuts in different positions so that the hovercraft travelled the distance of 60 cm at around the target time of 15 seconds. It was frustrating work -- the hovercrafts were inconsistent in their performance, which varied greatly depending on the level of the batteries, which, upsettingly, ran out of power very quickly and had to be recharged frequently.

At my first ever invitational at Ladera Vista, I (with the help of my partner) earned my first ever medal -- 2nd place. From there, we placed at every competition except for state (bad luck) and nationals (7th place!).


I did Thermodynamics in 8th and 9th grade. Thermodynamics was the first event that Mrgreencacti built something for, as Thermodynamics was a hybrid event, with both a study portion and a build portion.

Originally, I chose this event also because the name sounded cool. I started to study the topics involved, such as heat transfer, phase change, temperature, heat, and even things I had never heard of before, like entropy. At the same time, I and another Science Olympian started to work on the build portion of the event (separately). At the time, I reasoned that it would probably be easier to make a stationary insulation box than a working, complicated hovercraft. I tested all sorts of materials and judged their performance during 30-minute tests, comparing the final temperatures of water inside and outside the box. I did this in competition with the other Science Olympian, and the two of us regularly did these 30-minute tests on their own boxes that they filled with materials. These started from cotton balls and Styrofoam and advanced to polyurethane foam and Spaceloft aerogel. By the end, although my box was slightly less good (as proven by tests) than the other Science Olympian, because my Kraemer Scrimmage scores were higher, I was chosen to compete in Thermodynamics for the Blue team, with another Science Olympian who was a god at the study portion of the event.

At the first invitational, Ladera Vista, I accidently did a construction violation. The polyurethane foam had expanded to above the height limit for the box, and pushing it down counted as a "modification." So they got 14th place and I feared I would be kicked off the team. However, I stayed on the team and continued to place at all the invitationals and regionals.

By this point, the design for the box had been set in stone. A plywood box with layers of polyurethane foam inside, Spaceloft aerogel inside that, and reflective aluminum tape adjacent to the beaker with a polyurethane lid on top. With this box, I did over 200 total 30-minute tests, testing within the parameter ranges for temperature -- 60-90 degrees Celsius and 50-150 mL of water. After regionals, I devised a plan for the ice water bonus, which I would only use if the volume of water and initial temperature were significantly high enough to make a positive heat score tradeoff. This was tedious, and it was inconsistent throughout the entire process.

At state, my partner and I got 2nd place, one-upping Kraemer Middle School. At nationals, we got 3rd place, and this will remain my first and last nationals medal ever. Memorably, their prediction for final temperature was only 0.6 degrees off; however, Kennedy claimed theirs was 0.1 off. Kennedy won 2nd.

I continued with Thermodynamics in 9th grade. I developed a new method to predict final temperature using Newton's Law of Cooling and the exponential decay model that came with it. I did over a hundred tests and determined the k-value for cooling at different volume parameters (75-125 mL that year) and tested at different initial temperatures (60-75 degrees that year). I was sad to learn that the ice water bonus that had helped out so much at state and nationals the previous year was not a part of the event that year.

I also improved upon the design of the previous year. Division C Thermodynamics called for an even smaller box (15x15x15 cm compared to 20x20x20 cm for Division B). I took a thin cardboard box so as to not take up too much volume, and tested various polyisocyanurate (PIR) foams for insulation, eventually settling on Thermasheath from The Home Depot as a replacement for what had been polyurethane (PUR) foam the previous year. The layer of Spaceloft Aerogel stayed, and the lid was made of PIR (not Thermasheath, though) as well.

I worked together with the original science Olympian from Jeffrey Trail who had been in direct competition with him the previous year and together, they placed at every competition except for Mesa-Wilson. Notably, their prediction for final temperature at state was 0.0 degrees off the actual value, but they still got 5th place.

Circuit Lab

After Hovercraft went out of rotation in my 9th grade, I looked for another physics event to study for, and so I did Circuit Lab. I spent much of my two free periods at school writing notes for the event. I started by copying and pasting the study portion of the rules into a document. I took notes on every topic mentioned, organizing the notes by headers, subheaders, and even smaller subdivisions. I studied DC and AC power, Ohm's law, electrical properties such as resistance, current, voltage, and power, Kirchhoff's Laws, electric and magnetic fields, capacitors, logic gates, operational amplifiers, RC circuits and more. I studied relevant definitions and wrote down countless formulas and equations. These notes, over the course of several months, grew and eventually I had covered all topic areas defined by the rules. I added a table of contents and this document of notes became the binder for Circuit Lab.

Circuit Lab also had a lab portion, separate from the study. This meant performing a hands-on task on-site such as constructing a solenoid, creating series and parallel circuits on a breadboard, lighting LEDs, measuring time constants of RC circuits, and more. Therefore, I studied ammeters, voltmeters, and ohmmeters, as well as bought my own breadboard kit to experiment with various components, such as batteries, resistors, capacitors, transistors, LEDs, buzzers, and more.

I was eventually paired up with a partner with an even higher weekly testing average. We worked together at each competition and medalled in every competition except at state. Throughout the competitions, we studied their tests and took notes on new concepts in our binder to further broaden our knowledge.

In 10th grade, I continued to participate in Circuit Lab, and by the end of weekly testing, I and the same partner were chosen to compete for the A team. They adjusted their binder to account for slight changes in the rules and continued to compete and acquire new knowledge and experience in the lab portion.

By 11th grade, with the rerun of this event preventing it from rotating out, I had already forgotten much of the content for the event. Without a lab portion, scores would be determined solely by the written test, which could be seen as either a good or bad thing. For this year, I studied more comprehensively and cohesively, rewatching videos, learning more advanced content, and reading textbooks. Like with other events during my 11th grade year, the content of tests at competitions became more difficult, not as mandated by any changes in the rules, but simply because test-writers took it upon themselves to diversify and make things more competitive.

Fermi Questions

A "fermi question" is a question that seeks an immediate, imprecise estimate of a value. For example, how many piano tuners are in Chicago? At first, this might seem impossible to answer, especially without being given additional information. But using rough estimates and calculations, one can find an answer in the same order of magnitude as the true answer (the answer is 290).

In the Fermi Questions event, answers are given in powers of 10. Instead of writing "10^3," one would just write "3." Points are given based on how many orders of magnitude the answer is from the correct answer. Zero orders off is five points, one order off is three points, two orders off is one point, and any more orders off is no points.

Fermi Questions is notorious in SciOly for being unpredictable, not only in the content of questions but in placing as well. Generally, one can be "good" at Fermi Questions by knowing random facts and numbers (like the mass of the earth, distance of a light year, etc.), being familiar with factorials and logarithms, and knowing various physics constants (planck's, boltzmann's etc.). This is especially important since you cannot bring any materials (like cheatsheets or binders) to the event.

Most of the time, my partner and I ripped the test apart and worked individually on halves of the test, then reconvened on particularly difficult problems. A lot of the time, we disagreed, so we had to compromise.


I chose this event once again because it was a physics event, this time in 10th grade. The event involves understanding how to analyze simple and compound machines, specifically their mechanical advantage and other characteristics. As will be explained later on, other topics were added the next year.

I started taking notes to compile into a cohesive binder early on, and started to grasp the content of the event. A bit later on, I worked with another Science Olympian (who actually happened to have an event conflict with Machines) to work on a prototype for the Machines build portion. This involved constructing a compound lever system (involving a class 1 and a class 2 or 3 lever) to determine the mass ratios between three masses, which could range between 20 and 800 grams. I'll admit, the initial work on the Machines build was rather naive and primitive.

As the year went on, I increasingly worked on the Machines build alone. I used one upright board to support two levers, attached by ball bearings carved into them. The levers were just Home Depot (meter?)sticks, which was helpful because we could use the length markings on them as reference. The top lever was a class 1 lever with much more of its length on the right side than the left, and the bottom lever was a class 2 lever coming out toward the left; the whole system was set up to create a large mechanical advantage to accommodate for a large range of possible mass ratios. A counterweight (really just a sketchy conglomeration of black electrical tape) was placed on the short left end of the class 1 lever. Hooks were attached to strings which were looped around the levers, such that their positions on the levers (and thus the mechanical advantage of the compound lever) could be adjusted. Another Home Depot lever (which, by the way, was one that we messed up; a failed lever, essentially) was erected left of the left end of the class 2 lever using corner braces and mounted with some plastic pieces to restrict the movement of the lever and indicate where equilibrium was.

Much effort was put into figuring out how to connect the levers in series such that a) the levers would be in parallel when the system was in equilibrium and b) there would be no wiggle room or stretching. Simply using a string to connect the levers failed, and I eventually settled on using a rigid green strip and connecting the levers using metal wires.

The operation of the compound lever system relied on two "modes." We would feel the masses and identify roughly if the mass ratio is within 3:1 or beyond that. If It's within 3:1, we would place the lighter mass in the "mode 1" position on the class 1 lever such that the IMA of that lever is 1. If it's beyond 3:1, we would place the lighter mass in the "mode 2" position such that the IMA of the class 1 lever is 3. This way, we would have the most precise measure of mass ratio. Then, we would adjust the position of the lighter mass on the class 2 lever until the compound lever reaches equilibrium, and write down the measurement and refer to our data tables for the mass ratio associated with that measurement.

In order to produce these data tables, I had to go through testing each possible mass ratio and marking down what the measurement was on the lever. In the "gray area" between mass ratios of 3:1 and maybe 4:1, I had to test both modes. To complicate things, I found that using different mass values of the same mass ratio yielded slightly different measurements. For example, masses of 20 g and 40 g would yield a different measurement than 400 g and 800 g, probably because of slight unavoidable stretching in the connection between the levers. Overall, quite the draining ordeal.

In practice, using the compound lever system was quite a disaster. For almost all the invitationals we went to, we swapped the mass ratio around when we wrote down our answer (e.g. putting down 4 instead of 1/4). On top of that, after we realized the issue and geared up for the regional tournament, the regionals proctors for Machines messed up the masses by making them too large (and thus not compliant with the rules specifying the maximum vertical height of the masses) and so they would sit on the base of our build rather than hang from the levers. In the end, the event was basically trialed, but it was a huge disappointment, especially after all our preparation. Then to make things even worse, the state tournament was canceled that was the last time we would be able to compete in the build portion of Machines.

In 11th grade, the entire build portion was canceled as part of the MiniSO rules, to our disappointment. Notably, during this school year, the rules expanded to explicitly mention a lot of concepts of mechanics (i.e. kinematics, statics and dynamics, conservation of energy, momentum, etc.). Tests also got a lot harder, much harder than the previous year, involving more complicated systems of machines and mechanics situations to work through. My partner from the previous year also graduated and I spent this competition season constantly cycling through partners as teams were adjusted. The first invitational we went to this school year was BEARSO, an absolutely massive national-scale tournament. We were overwhelmed by the difficulty of the test and as a result scored very poorly. But after that wake-up call, I studied harder and was able to drastically improve my mechanics and machines skills and as a result placed consistently at later invitationals as well as regionals and state.

Sounds of Music

Sounds of Music was an event I joined sometime during the middle of the school year of 2019-2020, shortly before we went to our first invitationals. It was a combination of the physics and music theory of the event, which I already had some aptitude in, and the fact that nobody was working on an instrument for the build portion of the event at the time because our previous Sounds of Music people basically went AFK, that led me to join the event.

Sounds was maybe the most interesting event that I have studied for. In 10th grade, I covered all the basics of wave concepts, sound properties, sound phenomena (interference, diffraction, reflection, etc.), musical characteristics, music theory, and musical instruments compiling them into a binder. By 11th grade, the content of the event as dictated by the rules had not expanded, but tests generally became more difficult, covering niche (adherence to the rules being questionable) content such as architectural acoustics, as well as simply having more advanced concepts such as wave equations, sound absorption, more advanced music theory, and more specific information about the mechanisms of musical instruments.

For context, the sounds build portion requires that competitors create a musical instrument from scratch that is able to play the notes of a major scale in tune, with an octave jump between the 4th and 5th degree, the song "Twinkle Twinkle Little Star," and optionally, sound a bonus pitch an octave above the highest note of the scale or an octave below the lowest note of the scale.

I decided to create an aerophone consisting of a cylindrical pipe closed on one end with a single reed to produce sound, heavily influenced by the fact that I had just recently taken up playing clarinet and other woodwind instruments at the time. This was an incredibly unique choice; almost everyone else constructed a string instrument (overwhelmingly a guitar of some kind), or rarely, an idiophone. Thus, I never encountered a team that had decided to create an aerophone as we did at the many competitions we went to over the span of two years.

The tube was made of electrical conduit pipe, with holes drilled in at the theoretical locations for tone holes to produce the notes of an F major scale starting on F3, using the same fingering system as a Bb clarinet (although our instrument was not transposing). Adjustments to the holes were made in practice as necessary. For the reed, I tried to make a mouthpiece using the pipe and reed using basswood, but the sound would be oddly low-pitched, so in the end, we 3D-printed a mouthpiece and reed, directly using the clarinet design. This mouthpiece was then superglued on the top end of the pipe and the reed would be secured using a piece of tape.

Not all the tone holes could be covered using eight fingers, much like a normal clarinet (or any woodwind instrument for that matter), so I had to use a system of wooden skewers, plastic sheet fulcrums, rubber bands, and furniture pads to create two sets of keys (levers, essentially) to cover those holes. One of these keys went to controlling a register key up high near the neck of the instrument, which allowed the instrument to play higher notes on its third harmonic, which would prove useful for the scale requirement.

Leading up to our first invitational, we still did not have a plan to tackle the bonus pitch. Before building, I had envisioned that I could simply play a super high harmonic (basically "squeak") on the instrument by clamping down my embouchure on the reed. But I was not able to do this, upon trying. So, I set out to create a low note bonus pitch. I connected another pipe to the bottom of the instrument, which when played just so happened to sound an F2 in tune. The hole to cover was a fair way down the instrument, and required quite a long lever. Since a single lever would make the skewers stick out the sides too far, I had to create a compound lever (machines moment) so that the tone hole would be covered when I pressed the key with my pinky. Overall, the entire system was quite janky and had its own problems an inconsistencies. Any slight openings or incomplete coverings of tone holes would mean the low bonus pitch would not sound, instead sounding a harmonic. Furthermore, having the extra pipe attached to the instrument (which had to be attached during the whole competitions; removing it would be considered an alteration) meant the lower notes of the major scale became less resonant and more likely to squeak. In the end, we went with this system all the way up through regionals (state got canceled, however) and performed fairly well.

In 11th grade, only one invitational later on in the competition season was running the build portion (virtually). Prior to a week before this invitational, I had not touched my instrument the entire school year. When I picked it up for the first time in over a year, the problem of resonance in the low notes of the major scale persisted and the bonus pitch continued to be inconsistent. I set out to fix it. I increased the size of the tone holes to improve resonance and even experimented with using Play-Doh for key pads to make the tube more airtight, and tried my best to continue with that system. The day before state, however, I found it to be too inconsistent still and in a last-minute alteration, I replaced the key system with an inverted one: instead of opening when I pressed the key down, it would stay down by default (so I would constantly have to press the key when note playing the bonus pitch) and only open once I released the key. This way, the tone hole would be kept down by the tension of a rubber band, and would be more stable. Overall, pretty successful considering how unplanned it was.