Abstracts

Willpower depletion

Todhunter, K, Neuroscience

Conrado, A, Neuroscience

Just like any other muscle, the part of the brain that regulates willpower is hypothesized to become fatigued after repeated use. Many scientists have theorized that the prefrontal cortex regulates self-control and can be worked to exhaustion leaving willpower depleted. Since 1988, over 100 studies have contradicted or corroborated thus original hypothesis first popularized by Roy Baumeister. Our study aims to test if the prefrontal cortex can become fatigued through self restraint, depleting one's willpower. Baumeister used students’ abilities to ignore a plate of cookies to test willpower depletion, but instead of using cookies, we are using emotional self-regulation. Emotional self-regulation requires conscious effort, and, unlike cookies, doesn’t offer glucose. Glucose can re-energize the neurons in the prefrontal cortex giving the control group an inherent advantage. To compensate for this, our experiment tasks two groups of students to watch an emotionally triggering video clip while showing no emotion. After the video, they are tasked with finding a non-existent Waldo in a Where’s Waldo puzzle book. We are testing how long each student will persist in finding Waldo after viewing the video as well as how long each student persists without watching the video. Following our hypothesis, we found that, on average, students that watched the video gave up faster, as their willpower was depleted. The average attempt time after watching the video was 4.1 minutes, as opposed to the 5.1 minutes of those who did not watch the video. Those who did not watch were found to have an average of a 20% longer attempt time. This data follows our hypothesis, but in future experiments, it is important to find a consistent variable, as emotional videos are subjective and can affect people differently.

Location: SIC 102

The Effects of Music on Reaction Time

Shilakes, I, Neuroscience

Hudson, R, Electrical Engineering & Computer Science

In this experiment, we aimed to answer the question: does music enhances one's ability to focus and perform the task at hand? If so which genre? The Education Foundation conducted a study to answer this very question. In their study, they found that, yes, the introduction of music in an academic environment can help trick your brain into a “mood”. It is just a matter of knowing yourself well enough to personally induce the proper mood. Knowing this we wanted to take our research and experiment further. We wanted to pinpoint which genre of music would best augment our subjects reaction time. Although our data was inclusive, meaning that, for our test subject, there was no direct correlation or pattern to which genre helped the most. However, both students and faculty alike began to tap along to the beat of the music that they most liked. This indicates that if the subject assimilates to the genre of music they are more likely to stay focused, indicating that there was an increase in brain activity and proficiency.

Location: SIC 102

The Impact of Stress on Short Term Memory

Whitescarver, A, Neuroscience

Hyman, S, Neuroscience

Stiewe, P, Neuroscience

In our study, we explored how a stressor, like the noise of a car crash, affects short term memory. A study by Anatomy students showed that the noise of a car crash tends to increases stress. In these studies, stress was defined as increased cortisol, heart rate, and blood pressure. Our study relies upon solely blood pressure and heart rate to determine stress. To test its effect on short term memory retention, we separated our subjects into two groups: an experimental group and a control group. First, we took the baseline blood pressure and heart rate of our subjects. Then, our subjects all took a short memory test, consisting of 10 seconds to memorize the locations of objects on a paper and then 20 seconds to look at a new paper with the same objects, although now some have moved. While looking at this second paper the subjects were told to call out any objects that they thought had moved. During the memorization (encoding and storage in the brain) and subsequent retrieval of the memory, the experimental group listened to the sound of a car crash. The control group listened to nothing. Our findings indicated that there was no statistical difference in the memory or stress variables (blood pressure or heart rate) between the experimental and control group. Therefore, these findings suggest that the noise of the car crash did not cause our test subjects to be stressed and the noise did not impact short term memory retention.

Location: SIC 102

Determining the Mutagenicity of Lotions With and Without Fragrance Using the Ames Test

Johnson, K, Human Anatomy & Physiology

Stiewe, P, Human Anatomy & Physiology

Unlike other chemicals found in everyday cosmetic products, the FDA does not require companies to label the ingredients used for fragrance. An increasing number of studies have linked the unlisted chemicals in fragrances to toxicity. The purpose of this experiment was to evaluate the mutagenicity (chemical compounds that induce mutations in sample DNA) of two lotions - one that was unscented, and one that contained ‘Fragrance’ as one of its ingredients. To detect potential mutagenicity, we used the Ames test: a cheap, widely employed method of determining mutagenicity in chemical compounds using mutated E.coli bacteria. Our results indicate that the bacteria had a statistically greater level of mutation in the Eucerin lotion without fragrance than the Nivea lotion with fragrance, opposing our hypothesis that the lotion with fragrance contained a greater amount of mutagenic compounds. In the future, it would be beneficial to test a wider range of lotions, including lotions that include ‘fragrance’ as one of their top ten ingredients. Specifically, it would be valuable to find a way to isolate ‘fragrance’ as a variable. By expanding the scope of our experiment in this way, we could evaluate the mutagenicity of the products more comprehensively.

Location: SIC 102

Miracle Berries and Their Effect on Taste

Bednarz, E, Neuroscience

Lee, N, Neuroscience

Blum, R, Neuroscience

Our goal was to test the effects of miracle berries (miraculin) on different people’s perception of taste. We did this by feeding 10 subjects 1 salty, sweet, and sour food, and then had them rate the sweetness of the food from 1-10: 1 being not sweet, and 10 being very sweet. They then consumed the miracle berry tablet, and after it dissolved, ate the three foods again in the same order and rated the sweetness of the food once again. We found that the majority of subjects didn’t sense a change in sweetness of the salty food at all. However, some subjects’ perception of the sweet food altered, as it tasted more sweet after the tablet. Additionally, it affected everyone’s perception of the sour food, as it tasted drastically sweeter after the tablet was consumed. This was because of the chemical miraculin which is found in miracle berries (goji berries). The miraculin works by binding to sweetness receptors on your tongue, and making acidic foods taste sweet.

Location: SIC 102

Measuring Neural Activity Using an EEG

Chase, L, Neuroscience

Melrose, S, Neuroscience

We know that sleep is necessary for humans to survive, but it is not clear why that is. When we sleep, the brain cycles between deep and light sleep. The purpose of our experiment was to determine whether closing eyes increases or decreases brain activity, in hope of gaining insight as to why we actually need sleep. We defined high brain activity as high in frequency, low in amplitude, because these parameters correspond to high neural stimulation. We hypothesized that eyes open would have more of brain activity, because the visual input stimulates the brain, causing a higher frequency electrical output. To carry out the experiment, we used an electroencephalogram (EEG) to measure brain waves. The results from our experiment corroborated our hypothesis in that eyes open resulted in high frequency, low amplitude waves, while eyes closed caused slower (low frequency), high amplitude waves. To relate our results to brain activity during sleep, we took the fact that reduced no input takes reduces a large portion of brain stimulation. When the brain is fully awake, it must constantly adapt to its environment, causing a rapid, sporadic signal. A sleeping brain does not have to adapt as much, and can therefore produce a slower, more consistent signal. From this knowledge, we can infer that the brain needs sleep in order to take a break from the majority of sensory inputs. Sleeping gives the brain a chance to rest and conserve energy so that it is ready to adapt and function the following day.

Location: SIC 102

The Effects of Music on Pain Tolerance

Spitz, C, Neuroscience

Popell, L, Neuroscience

The goal of our project was to determine what type of music has the biggest impact on pain tolerance. While there are many different genres of music that would potentially impact pain tolerance, we decided to focus on “calming” and “distracting” music to see if relaxation or distraction would improve pain tolerance. Through our research we found two songs that have been tested to be either extremely calming or distracting. In order to test our subjects, we created three groups of nine people. A control group held their hand in ice water for as long as they could before removing it. Our “distracting music” and “calming music” groups listened to the music for thirty seconds before placing their hand in the ice water. Our results found that those listening to the “calming music” held their hands in the water for the longest (for an average of 2:21:40 minutes), followed by the “distracting music” group (with an average of 1:52:06). The group listening to no music held their hand in the water for the least amount of time (an average of 1:24:07). These results imply that both “calming” and “distracting” music increase pain tolerance, but “calming” music does so to a greater extent.

Location: SIC 102

The effect of moderate exercise on short-term memory

Kohlhepp, K, Human Anatomy & Physiology

Wadsworth, F, Human Anatomy & Physiology

Previous studies have shown that exercising can increase the brain’s short-term memory capacity. Some scientists say that this increase is due to an increase in blood glucose levels. The purpose of this experiment is to determine whether or not exercise is beneficial to memory. Test subjects took a short-term memory test in which they saw a list of numbers and then had to write them down in reverse order from memory. They then did a short workout which entailed doing 20 crunches, 20 pushups, working out on an elliptical or exercise bike for three minutes, jump roping for three minutes, and finally walking around the workout room for one minute. After the subjects completed the exercises, they took the memory test again to see how their scores had changed. Memory scores before and after exercise were compared with a paired sample t-test. There was statistical evidence that exercise improves short-term memory (p=0.04). This experiment is beneficial to both teenagers and adults who wish to better their study and work habits. Considering that most people look at their phones while taking a break from doing work, it would be very interesting to test the difference between these two types of breaks and just how much more beneficial exercise is to short-term memory than just looking at a screen.

Location: SIC 102

Effect of JUUL e-cigarette Fluid on the survivorship, locomotion, and development of C. elegans

Whitten, K, Advanced Biology

Angel, I, Advanced Biology

The company JUUL has taken the forefront of the increasingly popular e-cigarette industry. Because e-cigarettes are relatively new to the market, there has been little research done on their effects. In addition, JUUL is highly popular among teens, making it an extremely relevant topic for research. The objective of this study was to test the effects of JUUL fluid on C. elegans as exposed through their environment. We added dilutions of both 3% and 5% JUUL fluid to the agar medium and observed survivorship, development, and locomotion.

Location: SIC 106

Levels of Waterborne Bacteria at Four Sites within the North Bay Area and the Influence of Biodiversity

Jackson, E, Environmental Science

Cich, I, Environmental Science

Pollutants like E.coli, copper, and excess nitrogen in water can be harmful to both humans and ecosystems. In this study, we compared water samples from four sites around the Bay Area: Blackies Pasture, McNears Beach, Richmond Marina, and Berkeley Marina. Our principal research questions were: How do levels of water pollutants, specifically bacteria, vary at different sites around the bay and what influence does biodiversity have on water quality? Following procedure written by the Surfrider Foundation for the Blue Water Task Force, we took samples of water at 4 sites, tested for nitrates/nitrites and copper, and recorded the pH and temperature of the water using a Horiba Water Probe.While at these sites we used quadrat sampling to calculate the simpson's index of biodiversity at each site. After testing our samples in the lab for E.coli, total coliforms, and Enterococcus, we found that McNears (Coliforms: 328 MPN, E. coli: 0 MPN, Enterococci: 84 MPN) and Tiburon (Coliforms: 605 MPN, E. coli: 20 MPN, Enterococci: 0 MPN) had the least amount of bacteria. Our biodiversity results demonstrated that the McNears (.924) and Berkeley(.880) sites had the lowest diversity, and that Richmond (.799) and Tiburon (.641) had the most biodiversity. We found small amounts of other pollutants (copper and nitrates/nitrites) at every site. Our results suggest that biodiversity doesn't necessarily affect the levels of water pollutants, namely bacteria. Nearby land use like the industrial surroundings at both the Richmond and Berkeley sites, however, may influence water quality.

Location: SIC 106

Testing Nudges to Encourage Hand Washing Behavior

Swagel, E, Environmental Science

Mercy, J, Environmental Science

Wattis, E, Environmental Science

Studies have documented the importance of hand washing in public places. Infectious disease that is spread in homes, institutions and public places is an important concern. Our primary study addressed the spread of bacteria on the door handles at Marin Academy. Our goal was to test if nudges (simple cues in our environment that influence us to behave in a certain way) could convince people to wash their hands, in turn reducing the number of bacteria on door handles on campus. For our social nudge, we created posters with information about the danger of bacteria and how washing your hands can stop the spread of bacteria, and then we put the posters up on all the locations that we tested bacteria for. We tested 3 bathroom door handles for bacteria before and after the nudge. Prior to our nudge, testing revealed an average of 34 CFU/plate with the boys’ bathroom in the cafeteria hosting the most number of bacterial colonies (44.5 CFU) and the girls’ bathroom in the cafeteria hosting the least number of bacterial colonies (19 CFU). After studying the results of our bacteria tests after the nudge, we hope to be able to see how nudges can be applied throughout our school and other schools to influence handwashing behavior.

Location: SIC 106

Radish and Bean Seed Response to Sulfur Dioxide

Gallivan, A, Environmental Science

Orr, Z., Environmental Science

Clean air is a basic requirement of ecosystem and human health. Sulfur dioxide (SO₂) can impact human health by acting as an irritant to the eyes and lungs and ecosystem health by serving as a primary ingredient for acid rain. The Bay Area Emissions Inventory Report (2011) explained that sulfur dioxide emissions in the San Francisco Bay area are expected to increase 1% per year in the area largely as a result of combustion at stationary sources, like refineries. The goal of our experiment is to investigate the impact of sulfur dioxide (SO₂) on the germination and development of bean and radish seeds. In order to measure the effects of SO₂, we tested 32 seeds. Half of these seeds were not exposed to SO₂ and half of these seeds were exposed to SO₂. After 6 days, none of the seeds exposed to SO₂ germinated. However, 62.5% of radish seeds in the control group germinated and had an average root length of 2.8 cm and 87.5% bean seeds in the control group germinated and had an average root length of 2.5 cm. Our results suggest that SO₂ does negatively impact plant growth and in our case prevented the germination process from occurring. In a future study, we would like to investigate how fully matured plants would respond to SO₂.

Location: SIC 106

Investigating Epigenetic Differences in Aribadopsis Through Gel Electrophoresis and Observable Phenotypical Differences

Anderson, L, Advanced Biology

Paper, S, Advanced Biology

The purpose of this study was to investigate the epigenetic effect of DNA methylation of a gene and the relationship between genotypes and phenotypes of Aribadopsis plants. This study was part of a citizen science project by the Boyce Thompson Institute, which had the purpose of better understanding how methylation groups and other epigenetic markers affect Aribadopsis plants, a model species. Mutated (fwa-1) and non-mutated (Ler) plants were grown, their leaves were collected, and gene polymerase chain reaction and gel electropheresis were carried out. We added a modification dependant McrBc restriction enzyme that cuts DNA with Methyl groups. Our results from the gel electrophoresis showed that every sample had amplified DNA in it, indicating that we cannot demonstrate that the plants have different epigenetic genotypes on their flowering genes. Also, the observable characteristics of the plants such as height, coloration, and flowering time were noted. As for the observed differences, the plants have not yet grown enough to observe any real differences. However, it is expected that the mutated plants will flower at a different time, highlighting that the mutated plants have demethylated FWA genes, whereas the Ler have methylated FWA genes. This would imply that epigenetics play an important role in the reproduction of plants, opening up inquiry into the role of epigenetic methylation groups in the reproduction genes of other animals, such as humans. This could open up new areas to explore such as the role of environmental factors on the influence of gene expression.

Location: SIC 106

Impact of Fertilizer on Daphnia magna

Janney, L, Environmental Science

Sarti, E, Environmental Science

Fertilizer contamination is a well-researched problem; contamination from nitrogen and phosphorus fertilizers has been shown to have grave effects on ecosystems exposed to fertilizers. A 2018 study by the University of Girona aimed to test the filtration, swimming, and mortality rates of Daphnia magna when in the presence of ammonium, nitrite, nitrate, and phosphate. The study revealed that mortality rates within a population of Daphnia "increased with nitrite and ammonium concentrations, but not with phosphate or nitrate." (Serra, 2018). Our study aimed to demonstrate the impacts of fertilizer on Daphnia's heart rate. We observed Daphnia and counted and averaged their average heartbeat in a controlled (0% fertilizer solution) (157.2 bpm), a 0.5% fertilizer solution (258.2 bpm), and a 0.25% fertilizer solution (170.4 bpm). Our results suggest Daphnia exposed to a higher concentration of fertilizer had higher heart rates and thus more stress than the daphnia observed in our control data. Our next step would be to investigate the impact of fertilizers on other aquatic organisms.

Location: SIC 106

Organism Identification: A FUNgi Approach

Irwin, A, Advanced Biology

Sohn, J, Advanced Biology

This study examined how DNA isolation, amplification, and sequencing techniques are being used to help identify different organisms. Through the development of these procedures, scientists are able to both visualize and analyze DNA. A common application of these techniques is in the organism identification process. When comparing DNA sequences, there may be slight differences. Some may be as small as a change in one base pair, while others may affect dozens of nucleotides. However, looking at the DNA sequences alone, it is difficult to determine whether these differences are significant. For our project, we isolated, amplified, and sequenced DNA from six different fungi: Pseudoclitocybe cyathiformis (The Goblet), an unknown species from the genus Ramaria (Coral Fungi); an unknown species from the genus Entoloma, Hygrocybe acutoconica, Tubaria furfuracea (Scurfy Twiglet), and a possible Cuphophyllus fornicatus. We suspected that the majority of the organisms we tested will match species already in the database with at least 95% confidence. Three of our specimens matched sequences already in the database, and we therefore identified them as those species. However, two specimens did not completely match up with any species in the database, nor did they show any physical resemblance to any known species. Therefore, it is possible these are a new species of Cuphophyllus and Entoloma fungi. What we still plan to research is what the 95% confidence means and whether that 5% difference is significant, while still considering other qualities the organism (morphology, common names, citizen science observations and their reliability, etc.).

Location: SIC 106

Bacteria on MA Sports Equipment

Carr, J, Advanced Biology

Summersgil, K, Advanced Biology

Pedrero, B, Advanced Biology

70% of students play at least one of 32 different sports teams at Marin Academy (MA). Each of these sports has its own designated equipment. However, not all equipment is strictly monitored and sanitized, potentially allowing for an abundance of bacteria growth, which could lead to a multitude of health and sanitation issues. The goal of this study was to determine how much and what kinds of bacteria grow and live on different equipment here at MA. In this study, we tested basketballs, soccer balls, golf balls, soccer cleats, basketball shoes, and golf putters. We collected bacteria swabs from our samples both before and after we cleaned them with Lysol wipes. Our results demonstrated both the basketball shoes and the soccer cleats had an average of 983 CFU. We also determined that cleaning the objects with Lysol wipes had a drastic effect (1 CFU on average/plate) after cleaned. Next, we used EMB and MSA agar plates to test for the presence of gram-positive and gram-negative bacteria. The results of our EMB Agar tests suggested that there was little to no gram-negative bacteria on our items. However, the results of our MSA Agar determined that there was, in fact, a significant amount of gram positive bacteria on each of our items except for the basketball and the golf ball. Although we did have some EMB Agar growth from the soccer ball, our findings suggest that there is gram positive bacteria and future studies should aim to identify what types of gram positive bacteria are present and how it can affect athletes.

Location: SIC 106

Determining the Mutagenicity of Artificial Sweeteners Using the Ames Test

Prieto, S, Advanced Biology

Torto, S, Advanced Biology

Hee, C, Advanced Biology

Artificial sweeteners have become increasingly popular amongst the health conscious in the United States. Among the most common artificial sweeteners are Stevia, Sucralose, and Saccharin. The objective of our study is to determine the mutagenicity of these artificial sweeteners using the Ames test. The Ames test determines mutagenic activity of chemicals by observing whether they cause mutations in sample bacteria. We performed the Ames test with Stevia, a liquid (called Crystal light) with sucralose as one of the ingredients, and Sweet and Low, which is made from granulated saccharin. We found that Stevia had a negative result, Crystal light had a positive result, meaning that it mutated, and Sweet and Low had a positive result. These findings could motivate more studies to be performed on artificial sweeteners, which is fitting because they are becoming increasingly popular. In addition to studying the mutagenicity, a call for future research could be testing these agents (Crystal light and Sweet and Low) for potential carcinogenic reagents.

Location: SIC 106

Like Clockwork

Williams, M, Astrophysics & Astronomy

Bailey, J, Astrophysics & Astronomy

Our objective in this project was to determine whether or not we can construct a ticking clock device that ticks at regular intervals using the following materials: Universal Laser Systems laser cutter, MDF, off the shelf bearings, dowels, and Adobe Illustrator. Clocks have played an important role in the history of astrophysics due to their connection to longitude. Throughout much of naval history, ship captains had no reliable way of determining their longitude while on the water. Mechanical clocks at the time were not effective on boats because the waves and moisture in the air skewed their ability to hold a constant time. Eventually, British inventor John Harrison solved the longitude problem by developing a clock that could hold constant time while at sea and consequently allow ship captains to determine their longitude. For our Science Symposium project, we aimed to recreate a simplified version of a mechanical clock. The bulk of our work time was spent researching the mechanisms of different types of clocks and building the escapement device that would allow us to regulate the speed at which our device ticked. Without the escapement, the ratios between gears on the clock would function but time would just freely drain out. Due to time constraints we were only able to assemble an escapement and did not add second, minute, or hour hands. We were able to have the escapement let one tooth of the gear by reliably for about 15 seconds, then it begins to spin faster. This is due to the dowels not being at 90º angles and the wood frame attached to the base being offset.

Location: SIC 107

The Phenomenon of the Crookes Paddle Wheel Tube: Do Electrons Carry Sufficient Momentum to Accelerate a Rigid Rotor?

Ringness, E, Astrophysics & Astronomy

Brunn, K, Astrophysics & Astronomy

Physics relies on the knowledge that electrons carry momentum, mass, velocity, and Kinetic Energy. This experiment used the turning of a cathode ray paddle wheel to determine this, following the Crookes paddle wheel experiment. We compared the electrical power and mechanical power needed to move the paddle wheel. We applied a voltage to the cathode ray tube, sending a beam of electrons through it, as that beam is attracted to the side with the opposite polarity voltage. We then used a multimeter and calculations to determine the electrical power. In order to find the mechanical power we tested the motion of the paddle wheel as a result of only gravity. Using Logger Pro video analysis software, it is possible to graph the increasing acceleration of the paddle wheel as it moves due to gravity. The final step is, in comparison, if the electrical power is about equal to the mechanical power that would indicate that the momentum of electrons could be enough to initiate the acceleration of a static rotor on the interior of the Crookes Paddle Wheel Tube.

Location: SIC 107

Efficacy of Toroidal Distributions in Tesla Coils

Byrne, S, Electrical Engineering & Computer Science

Epstein, F, Electrical Engineering & Computer Science

In culmination of our Electrical Engineering and Computer Science class, we decided to test the efficacy of toroidal distributions in Tesla coils. To do this, we constructed a Tesla coil and several toroids, then drew the shaped fields we observed with an LED. To build the Tesla coil, we first began by constructing our primary and secondary coils that would later be the source of voltage induction. Our primary coil was constructed out of three loops of thick wire and our secondary coil was constructed out of about six hundred loops of 30-gauge magnet wire. These coils were mounted coaxially on a piece of wood, which we also used to mount the spark gap (made with two screws) and the capacitors (comprised of Snapple bottles wrapped in aluminum foil and filled with salt water and mineral oil). We built three sizes of toroid, all in the shape of a dome, hypothesizing that the largest of the three would be most effective. However, due to the duration of the coil construction period, we are unable to provide any results at this time. We plan to test the efficacy of different toroid shapes in the coming week. All results and summaries will be detailed on our final poster.

Location: SIC 107

Guitar string Oscillation Indicating High Frequency Overtones

Johnson, K, Astrophysics & Astronomy

Grassi, G, Astrophysics & Astronomy

Sarosi, M, Astrophysics & Astronomy

By analyzing the wavelength patterns of a string connected to a speaker, we are testing the functionality of different guitar strings to see which creates more high frequency overtones. We are expecting to find that flat strings will have less high frequency overtones in comparison to round-wound strings which create a brighter sound. We are conducting these tests by standardizing the tension and length of bass strings of different materials and shapes. The string is attached to a speaker and oscillates according to the frequency we play. In observing this occolation we can see visible nodes that indicate the overtones determined by the frequency of certain strings. We hope to measure the intensity of high frequency overtones by observing the frequency response of certain strings.

Location: SIC 107

What Beat Frequencies Are Most pleasing?

Rajapakse, T, Electrical Engineering & Computer Science

Haggerty, E, Electrical Engineering & Computer Science

Hershman, J, Electrical Engineering & Computer Science

Our research question is: What beat frequencies are most pleasing? In our research we studied different frequencies and how humans perceive them. In On the Sensations of Tone As a Physiological Basis for the... by Hermann von Helmholtz and Alexander John Ellis, they say that perfect thirds, fifths, etcetera, as long as they are prime numbers, create noises most pleasing to the human ear. Our project seeks to deepen our understanding in this area using our local population. In our experiment we gathered an assortment of tones, some of which were in the category of perfect notes, others were more random frequencies which we decided upon. We gave our participants the ten different tones which we chose. Then we had them rank them in the order of most pleasing to least. Variables which we wanted to take into account were the age and gender of the participant, and discover whether or not these variables impacted the results from different groups participants. We were able to get this data by having the subjects fill out an online quiz which we created for them to answer the questions. So far the responses we have gotten seem to generally reflect the idea that frequencies around the consonant intervals are most pleasing. We are currently still testing and plan to continue until we are satisfied with a large enough research group.

Location: SIC 107

Double Slit Experiment

Smith, W, Astrophysics & Astronomy

Heffelfinger, N, Astrophysics & Astronomy

For this project, we were interested in learning more about how light behaves, a central topic in our astrophysics class. We also wanted a project with a hands-on component. We decided to recreate the double-slit experiment, which supports that light acts as a wave. The experiment works because when waves hit an edge (such as one of our the edges of our slits), it reradiates that light from the point, creating multiple waves of light that interact with each other to ultimately create an interference pattern. Because the distance between the points in the interference pattern and the wavelength of light are proportional, through observing the pattern, we can determine the wavelength of light. Our essential question is: Is it possible to measure the wavelength of light with a homemade double slit experiment and how does the accuracy of wavelength measurement vary across different forms of the double slit experiment? To answer this question, we tested two different light sources with three different mediums. We tested each medium with a red and a green laser pointer with known wavelengths. Our three mediums were a pre-made diffraction grating, a double slit that we laser cut, and a lice comb. In the end, we learned that, while it's more difficult to get accurate measurements from the laser cut double slit and the lice comb because of the distance between the slits, overall, our results were fairly accurate with some margin of error.

Location: SIC 107

Attenuation efficacy of Faraday cages composed of various metals on common wireless communication frequency bands

Stromberg, S, Electrical Engineering & Computer Science

Lee, N, Electrical Engineering & Computer Science

Stone-Grijalva, A, Electrical Engineering & Computer Science

As cell phones become more ubiquitous in our culture, it has become inherently more critical to understand the efficacy of blocking mechanisms for cell phone signals. Although active cell signal jammer devices which emit electromagnetic frequencies have been made federally illegal, passive blocking devices such as Faraday cages remain entirely legal. In principle, a Faraday cage acts as an electromagnetic shield by using a grid of grounded metal to distribute outside electrical charges throughout the grounded material, effectively canceling the charge. In this project, we strive to determine the attenuation efficacy of different composition metals for Faraday cages in blocking modern cell signals, typically between 800 and 2500 MHz. To accomplish this, we measured the ability of a control phone to receive phone calls within a Faraday cage composed of different materials. We constructed Faraday cages of varying sizes and with varying grid hole sizes. We used the following principal materials to measure these various Faraday cages and their attenuation efficacies: aluminum foil, tin foil, copper foil, and steel mesh. In addition to measuring whether or not a control phone can receive a call (a threshold), we also measured the actual cell signal strength using a measurement application on the target phone. In general, our results have shown that a combination of aluminum and copper foil in close proximity to but not in contact with the device, provide the most electromagnetic shielding of the device and will successfully block cell signal.

Location: SIC 107

Change of Cosmic Ray Flux in Different Weather Conditions

Cohen, M, Electrical Engineering & Computer Science

Nguyen, L, Electrical Engineering & Computer Science

Cosmic rays are a form of radiation, existing in two types: primary and secondary. Cosmic rays also happen to have the highest energy existing in the form of radiation Primary rays mainly exist in space and they travel at around the speed of light. When these rays enter the Earth’s atmosphere, they collide with air molecules and form a different stream of cosmic rays called secondary cosmic rays. These are the rays that we are able to detect and they are mainly made up of muons, which are very similar to electrons, the difference being that they are 200 times heavier than a regular electron. We wanted to detect these muons and did so by building a detector using an AND logic gate and two vernier radiation sensors. We knew for a fact that changes in temperature affect how many air molecules are in the atmosphere and since muons are a product of cosmic rays colliding with air molecules, we saw a potential correlation. Therefore, we decided to analyze the effects of weather on the amount of muons that were detectable.

Location: SIC 107

Construction of a Helmholtz Coil for Manipulation of a Cathode Beam in Order to Derive the Charge-Mass Ratio of an Electron

Thompson, Z, Electrical Engineering & Computer Science

Salesky, N, Electrical Engineering & Computer Science

The electron forms the basis for all electrical engineering and computer science. As the integral component of physics it is, the electron plays a role in many natural forces and calculations. One key aspect of the electron that we chose to derive on our own was its charge-mass ratio. In order to run this experiment, we first needed to build a stable magnetic field. We decided to do this using a Helmholtz coil. A Helmholtz coil consists of two magnetic coils run in series with the same voltage and current that together create a magnetic field between them whose constant strength can be calculated. This magnetic strength is needed in the equation to calculate the charge/mass ratio of the electron. We assembled the Helmholtz coil using laser cut wood for the frame and 97 loops of 30 awg magnet wire for the coil itself. This was hot glued together with the dimensions and structure needed for our experiment. Once we assembled the coil, we placed the cathode ray tube inside and measured the distance that the laser was displaced with and without the activation of the magnetic field. We then used this measurement to calculate the magnetic field strength, which we then used in turn to calculate the charge/mass ratio of the electron. As a whole, our research demonstrates how interconnected electricity and magnetism truly are as parallel forces and how simple it is to derive key aspects of one from the other.

Location: SIC 107

Electromagnetic Manipulation of a Cathode Ray to Determine the E/M Ratio of an Electron

Friedman, S, Electrical Engineering & Computer Science

Setchko, X, Astrophysics & Astronomy

Boes, E, Astrophysics & Astronomy

Cathode rays were developed in the late 1800s as a way to better understand the atomic structure, allowing the user to view electron beams. By manipulating the beam and using the deflection plates of the ray to restore it, a cathode ray can be used to find the charge-mass (E/M) ratio of an electron. We used a magnet to change the magnetic field around the cathode ray, causing the beam to warp, and used a magnetic field sensor to measure the degree to which the magnetic field was changing. After using the deflection plates of the cathode ray to restore the beam to its original position, we used the measurements of the magnetic field, deflection plates and more to calculate the charge-mass ratio. Using J.J. Thomson’s original paper and previous Marin Academy experiment papers, we found the equations necessary for us to calculate the E/M ratio, which we plugged our values into. We found our ratio, 1.99x10¹¹, to match the expected ratio, 2x10¹¹. After completing these calculations, we used the example of a previous experiment using a wine bottle to create a cathode ray as a way to take our explorations further. Through using a wine bottle, wire, a vacuum tube, and high voltages, we were able to see how a home-made cathode ray tube worked. Ultimately, this process allowed us to gain a deeper comprehension of the electron and the significant role it plays in the structure of our lives.

Location: SIC 107

Deflecting Cosmic Ray Muons with a Magnetic Field

Wintersteen, A, Astrophysics & Astronomy

Taylor, W, Astrophysics & Astronomy

The goal of our project is to determine how effective a magnetic field is at deflecting cosmic ray muons and other high-velocity charged particles. The experiment consisted of two radiation detectors, one placed above the other, measuring the amount of muons detected in a certain amount of time. Due to their high velocities, cosmic ray muons are able to penetrate and be detected by both sensors, where as most other radiation particles are not. We measured the muon count over an interval of 24 hours, both with and without a magnetic field in the way. Without the field, we got an average of 6.917 muons and a median of 7 muons every 4 minutes. With the field, we got an average of 5.461 muons and a median of 5 muons every 4 minutes. These results suggest that although most of the muons passed through the magnetic field, the field did, in fact, deflect some of the high-energy particles.

Location: SIC 107

The Resonant Frequencies of Snare Drum Strings

Logan, V, Astrophysics & Astronomy

Weir, C, Astrophysics & Astronomy

Doyle, S, Astrophysics & Astronomy

We collected the data of frequencies in Hz and their amplitudes released after a snare drum was hit, and based on those results played tones into the snare drum at different frequencies. Our goal was to identify the frequencies that resonate with the strings of the snare. We found that 122 Hz had the lowest amplitude of the lowest frequencies we could play. We used it as the baseline for non-resonant frequencies, which are frequencies that will not cause the snare strings to oscillate. After playing a tone, we determined the intensity of the response due to resonance by measuring the sound pressure of the response. After playing the baseline frequency at 122 Hz, we looked to the peaks in amplitude of the snare drum hit in order to find other frequencies to test. We found that there was a correlation between a higher amplitude of a frequency and a higher sound pressure. For example, the highest amplitude from the snare drum hit was in the 160 range and a 167 Hz tone resulted in the greatest sound pressure.

Location: SIC 107

Modeling and Scaling the Heart Rates of Daphnia Responding to Acid Stress

Johnson, K, Advanced Chemistry

Brown, J, Advanced Chemistry

Scientists often look at biological factors to determine whether changes in the environment are affecting the present living organisms. Daphnia Magna, commonly known as the water flea, are often used in experimentation because of their affordability and transparent body - making it easy to measure heart rate. In this study, we explored whether an inverse correlation between daphnia heart rates and pH of a solution exists - and could be graphically or mathematically quantified, by creating six buffer solutions ranging from a pH of 4.5 to 7 by titrating HCl into a pH 7 buffer solution with a phosphate base. We generated 18 plot points: putting three daphnia in each buffer solution for five minutes, and then testing each daphnia’s heart rate using a 4* magnification microscope. After finding these data points, preliminary results show that there is a relationship between heart rate and pH: as the solution pH decreased, the average daphnia heart rate increased, supporting our hypothesis.The next step will be using the data to create an equation or mathematical equation. Because our equation was only based on the plot points we had, in the future it would be beneficial to collect a wider range of data in order to more accurately reflect a varied daphnia population. Additionally, it is worth considering whether daphnia could be used as a pH indicator: though it is affordable, the methodology is variable and comparatively time-consuming.

Location: SIC 206

The Effects of Olfactory Stimuli on the Autonomic Response to Auditory Stressors

Wilson, O, Neuroscience

Dawson, M, Advanced Chemistry

Schilz, M, Neuroscience

The rise of aromatherapy builds upon neuroscientific discoveries revealing the olfactory system’s direct link to the limbic system, a brain structure critically important to memory and emotion. Through this study, we explored short-term effects of contrasting scents on a person’s autonomic nervous system (ANS) response to auditory stressors. During each test, subjects listened to an auditory stressor with intermittent exposure to three different scents. In the lab, we synthesized one of the scents by reacting methyl alcohol with salicylic acid to make an ester, methyl salicylate, which mimics a wintergreen smell. We also used diluted butyric acid, an acid found in foul-smelling things such as skunk spray and vomit, and a placebo. Heart rate and blood pressure were recorded before and during exposure to each scent, and subjects were asked to identify their stress level on a one-to-ten scale. Our results showed that the wintergreen ester resulted in an average decrease in heart rate (-2.3 BPM) and blood pressure (-2.2 mmHg), suggesting a reduced autonomic stress responses to auditory stimuli. In contrast, butyric acid caused an average increase in heart rate (4.2 BPM) and blood pressure (2.4 mmHg), suggesting that an ‘unpleasant’ olfactory stimulus may heighten a person’s ANS response. Furthermore, subjects consistently reported greater uneasiness in response to the auditory stimulus when smelling butyric acid than when smelling the wintergreen ester. With these positive physiological and psychological impacts more relevant than ever, such data may help to further the applications of olfactory stimuli as relaxants.

Location: SIC 206

An investigation of the relationship between molecular structure and rate of evaporation of ketones and alkanes

Haase Cox, S, Advanced Chemistry

Hamovitz, N, Advanced Chemistry

Ketones are increasingly being used as organic solvents because they are not considered volatile organic compounds (chemicals that can cause negative health effects) and are therefore not restricted under air quality regulations. Ketones are identified by their carbonyl group, which consists of a carbon atom double bonded to an oxygen atom. Alkanes, another potential solvent, are saturated hydrocarbons made of single-bonded hydrogen and carbon atoms. Alkanes, unlike ketones, do not contain a carbonyl group. For industrial uses, chemicals with lower evaporation rates are preferable, as less chemical is needed making them more economically and environmentally sustainable. With this in mind, our experiment aimed to test the evaporation rates of several ketones and alkanes, and compare this to their molecular structure to make a conjecture as to the effect of structure on the evaporation rate of potential chemical solvents. The chemicals tested were: acetone, butanone, methyl isobutyl ketone, a mixture of several hexanes, pentane, and n-heptane. We tested the rate of evaporation by submerging temperature probes wrapped in filter paper in each chemical before removing them and allowing the chemical to evaporate, measuring the temperature change and time required to reach the lowest temperature. Our preliminary results suggest that molar mass is the greatest factor in evaporation rate. However, when comparing alkanes and ketones of similar molecular weight, the alkanes evaporate twice as much as the ketones and do so twice as quickly. This suggests that ketones would be much better suited to industrial applications, due to their lower rate of evaporation.

Location: SIC 206

The Effect of Polarizers on Various Wavelengths

Watson, J, Physics with Algebra & Trigonometry

Iannuccillo, A, Advanced Chemistry

Raja, I, Advanced Chemistry

Polarizing filters, when turned at a specific angle at a light source, can eliminate reflections and suppress glare. Unpolarized light, which vibrates in all directions, is polarized when transmitted through a polarizer; the emitted light oscillates in one direction while the rest of the light is absorbed. In order to determine the effectiveness of polarizers with various colored light, we measured the impact polarizers had on various wavelengths. We hypothesized that the amplitudes of sine curves produced from higher frequency wavelengths would be larger than the amplitudes of lower frequency wavelengths. We shined white, blue (405 nm), and red (650 nm) light through two distinct polarizing filters, one from an optics kit and one from a camera, under the exact same conditions. We collected the luminous emittance (lux) using a Vernier Light Sensor at various angles and fit sine curves to these data points. We used the white light trials, which verify Malus’s Law, as baselines and compared the amplitudes of the sine curves of the red and blue light to determine the amount of light absorbed at various angles. Through analyzing the amplitudes for both polarizers, we discovered that the red light trials produced smaller amplitudes than the blue light trials, demonstrating that effectiveness of a polarizer to absorb and polarize light declines as the wavelength of the light entering the filter increases. This has implications regarding photography; when photographing a sunset with intense red colors or when sunlight is redder, these polarizers would not have the intended impact.

Location: SIC 206

The Effect of pH of Cephalexin and Amoxicillin on a Culture of E. Coli Bacteria

Jacimovic, N, Advanced Chemistry

Parsons, T, Human Anatomy & Physiology

Taylor, W, Human Anatomy & Physiology

Dealing with antibiotic overuse is one of the most pressing issues in the medical world. Our experiment hoped to search for a solution by altering the pH of common antibiotics. pH is the measurement used to denote how alkaline or acidic a solution is. The lower pH meaning an acidic solution, a higher value an alkaline one. The purpose of this study is to investigate if and how different pH values affect an antibiotic’s effectiveness by altering the pH by ± 1, and measuring the zone of inhibition created by each sample of antibiotic. Our tests were conducted with lab grade samples of the bacterias E. Coli and Bacillus and the antibiotics Amoxicillin and Cephalexin. Amoxicillin’s pH is 5.85 (determined by pH probe), and a Potassium Biphthalate buffer was used to create a more acidic 4.85 pH amoxicillin fluid, and Sodium Phosphate (Dibasic) buffer was used to create a more basic 6.85 amoxicillin liquid. Once samples of the antibiotics with altered pH were created, we used sterile disks to expose a plate of each bacteria to each sample of antibiotic, in addition to a positive control of a 10% bleach solution and negative control of sterile water. By comparing the area in which the growth of bacteria was inhibited by the antibiotics, we determined that the E. Coli plates displayed that both amoxicillin and cephalexin are more effective at a lower pH. This initial interpretation warrants further research into whether or not this trend continues. The bacillus was inconclusive due to a fungal growth compromising the response.

Location: SIC 206

Cell Potential of Different Half Cell Metals with Zinc in a Daniell Cell

Clements, T, Advanced Chemistry

Rudnick, S, Advanced Chemistry

Thompson, Z, Advanced Chemistry

The purpose of the lab was to find the most efficient Galvanic Cell— or battery, in layman’s terms— using different metal electrodes in order to maximize the voltage output. The Daniell Cell relies on two half cells transporting electrons from an anode to a cathode through two solutions and a porous pot or salt bridge to create a voltage. The electrons that were pulled off of the electrode in one half cell move through the porous pot and into the other half cell, where they combine with the ions in that cell’s solution. The present study attempts to compare the cell potential of a Daniell Cell using zinc in one half cell and copper, iron, or lead in the other. Copper solutions were tested preliminarily using three different concentrations (.03 M, .05 M, .07 M) and identical voltage readings from the test suggest that if the cathode exists in excess, a solution will produce the same voltage at different concentrations. Using the voltmeter readings, the conclusion reached by this study is that of the three metals, copper has the highest cell potential, lead the second, and iron third of 1.052, .639, and .545 V respectively. Lead is extremely toxic, and iron produced a low voltage. Therefore, copper is the optimal metal for the Daniell Cell. The data suggests that the industry wide practice of using copper in common household batteries is the most efficient and safe way to construct a battery on a consumer scale.

Location: SIC 206

The Effects of Temperature on the Action Potentials of Mimosa Pudicae

Anderson, L, Advanced Chemistry

Scannell, C, Neuroscience

Much like those produced in the human body, the Mimosa Pudica plant produces action potentials. When its leaves or stems are touched, mechanoreceptors are triggered, causing their stems to fall and their leaves to close. The cells of the Mimosa plants pump chloride, potassium, and calcium ions through their membranes when they are signaled to do so by the action potentials, in a process called osmosis. While it is widely understood how action potentials function in Mimosa Pudica plants, this experiment was conducted to explore a less studied area: how temperature changes of the soil surrounding a Mimosa Pudica affects the amplitude and length of their action potentials. The action potentials of the plant were tested using a plant Spikerbox when the Mimosa was firmly tapped. Despite previous research showing that adding ice to the soil causes the action potentials to get smaller or even not happen, our preliminary testing demonstrated that the action potentials of both plants with and without ice were very similar. However, further testing will be carried out to try to bring the whole plant to a lower temperature, potentially by refrigerating, rather than just adding ice to the topsoil, in order to get a better sense of temperature’s effect on the plant.

Location: SIC 206

Measuring the Effect of Different Music Genres on a Human Body’s Heart Rate

Diamond, A, Physics with Algebra & Trigonometry

Goldin, K, Physics with Algebra & Trigonometry

Pu'u II, J, Physics with Algebra & Trigonometry

Recent studies have demonstrated that listening to different genres of music has an effect on the human body. Heart rate, a function of pumping blood through veins throughout the body, is directly affected by an emotional reaction when listening to music. It is known that the human heart rate generally rises when one becomes excited, scared, or put under physical stress. In the human body, a rise in heart rate triggers the release of the chemical adrenaline. Adrenaline affects the brain by tricking it into quickening reaction times. It can be inferred that when the heart rate rises, adrenaline is released. “Emotional reactions” generally result in a rise in heart rate due to emotions such as pleasure, happiness, or fear. The purpose of this experiment is to investigate and better understand the relationship between music and how it affects the human heart rate. The genres that will be used are alternative, rhythm & blue, hip-hop, and country. The sub-genres are lofi (mellow), country (mellow and rock), rap (mellow & uptempo), and rhythm & blues (mellow and upbeat).

Location: SIC 207

Detecting Radiated Heat through Various Materials

Detecting Infrared Radiation Through Various Materials

Hopkins, S, Physics with Algebra & Trigonometry

Ghobadian, S, Physics with Algebra & Trigonometry

Infrared waves are a kind of wave on the electromagnetic spectrum just outside of the range of visible light, but humans can detect them as heat. By detecting infrared waves, infrared cameras are able to detect and capture radiated heat and show it with a thermal image in which the hottest areas appear red, and the coldest blue. Because we were interested in analyzing such images, we decided to investigate this for ourselves with our experiment. We posed the experimental question: how do the qualities of different materials affect the temperature of the infrared rays which they allow through? We hypothesized that if we increase the thickness or opaqueness of a material between a person and our infrared camera, cooler infrared rays will be allowed through because a thicker material will block any kind of wave more efficiently than a thinner one, and an opaque material will block electromagnetic waves more efficiently. To test this, different materials were held in front of a person’s face, and the temperature of the infrared rays allowed through the materials was compared to the temperature of the infrared rays which she emitted alone. Our materials ranged in both thickness and transparency, which allowed us to draw conclusions about both relationships that we were testing. We found that lower temperatures were allowed through thicker and more opaque materials, whereas higher temperatures were allowed through thinner and more transparent materials.

Location: SIC 207

The Effect of Guitar String Thickness on the Energy in a Wave Length and Maximum Sound Intensity

Maxwell, B, Physics with Algebra & Trigonometry

Croteau, J, Physics with Algebra & Trigonometry

Guitars come in a variety of different sizes; each designed with specific intent, and with special strings to best compliment their design. Because thicker strings vibrate slower and longer due to them containing more lasting energy, it takes longer to disperse; Building off this, we looked at the contrast between thick acoustic guitar strings and thin electric strings in relation to the energy in each wavelength and the maximum sound intensity. To do this, we began by finding the fundamental frequencies and wave speeds on different strings using the Vernier Standing Waves on a String experimental set up, along with the tension, amplitude, and linear density. These were all needed to calculate the energy in a wavelength, and we did this by plugging the values into the wavelength energy equation: E𝛌=(½)𝜇𝜔²A²v. Furthermore, we took sound readings from each individually plucked string with a Sound Level Meter and gathered data for the maximum sound intensities of each string. Our findings showed that, for acoustic strings, there is a direct correlation between string thickness on energy in a wavelength and maximum sound intensity; unfortunately, we were not able to see this relationship in electric guitar strings due to discrepancies in pre-specified tensions. In the future, our project could be further expanded to see how guitar string frequencies affect the induced electromotive force output produced by a guitar pickup.

Location: SIC 207

Impact of Reverberation Time on Retention in Public vs. Private High Schools

Sandoval, N, Physics with Algebra & Trigonometry

Abbushi, C, Physics with Algebra & Trigonometry

Studies have correlated higher reverberation time with a decreased ability to focus and learn in the classroom. We chose to focus on how acoustics are related to educational inequity; more specifically, if there is a correlation between higher reverberation time and amount of retention in english classrooms in public high schools. For this project, we collected sound level data in classrooms at Marin Academy and one other local public school, Sir Francis Drake, using a Vernier Sound Level Meter. Then, we assessed the retention abilities of study participants through a simulated learning environment. Our preliminary results supported a correlation between english classrooms in public high schools having higher reverberation times than their private school counterparts, and volunteers did show a somewhat decreased ability to learn in these rooms. However, given our small sample size of classrooms and volunteers, our data neither supports or contradicts our hypothesis. While developing this project, it was difficult to get other schools to agree to test and to find volunteers willing to assist us. This experiment should be understood as more of a microcosm of how a larger experiment like this would be conducted, rather than a conclusive answer to our hypothesis.

Location: SIC 207

Analyzing the Impact of Angle on a Volleyball's Motion by Comparing a Floater and Overhand Serve

Prieto, S, Physics with Algebra & Trigonometry

Dewane, R, Physics with Algebra & Trigonometry

Reyes, J, Physics with Algebra & Trigonometry

An effective volleyball serve is crucial to winning a volleyball game. Many biomechanical factors are at play during a serve to help ensure a smooth transfer of energy from the hand onto the ball. Our experiment mainly looks into how the angle that a hand hits a volleyball affects the velocity of the direction the ball moves, as well as how far it travels. Our data compare two types of serves in volleyball: an overhead serve and floater serve. We recorded the serves several times each and used LoggerPro Video Analysis to quantify factors such as the angle and velocity of the serves. The data we gathered here allowed us to calculate how far the ball traveled, as well as the velocity. We found that, overall, hitting the ball using an overhand serve, with a larger angle, produces a higher velocity serve and travels the farthest distance. These findings could be useful for any volleyball players wanting to improve their winning strategy and the angle of their serves. We only used one person's serve in our experiment, so in the future, we could broaden our experiment to include more people, to determine whether the pattern holds true for the larger volleyball community.

Location: SIC 207

The Effect of Tempo on Human Heart Rate and Blood Pressure

Steinle, A, Physics with Algebra & Trigonometry

Maxwell, B, Neuroscience

Previous studies have shown that music is able to evoke a psychological effect from its listeners through activating the sympathetic and parasynthetic nervous systems. Through understanding the psychological effects of music on the body, our study investigates the physiological effect of music, specifically tempo, on the body through analyzing heart rate and blood pressure. This study was performed in an effort to better understand the body’s reaction to music with fast and slow tempos. Through measuring the heart rate and blood pressure of our subjects at their baseline, after listening to two minutes of Ed Sheeran’s Thinking Out Loud (78 BPM), and Guns N’ Roses’ Sweet Child O’ Mine (128 BPM), we concluded that Sweet Child O’ Mine evoked a higher pulse and blood pressure than that of Thinking Out Loud when compared to the resting vitals of our subjects. These results match our initial prediction that songs with faster tempos heighten heart rate and blood pressure while songs with slower tempos have the opposite effect. In the future, our findings could be used in order to heighten or calm the body’s vitals, making music a tool to manipulate the basic physiological aspects of the human body in everyday life.

Location: SIC 207

Long Exposure Techniques To Optimize Astrophotography Capabilities for iPhones

Levitan, J, Advanced Physics with Calculus

Moriyama-Gurish, A., Advanced Physics with Calculus

The night sky has captured the imagination of many as they stare up in wonder at the constellations. However, capturing the images of the night sky, especially on a personal cellular phone, is difficult. Often, the resulting image will not capture the light emitted from the stars and the photo will be completely dark. This project serves to address which method should be employed on the iPhone in order to best capture astronomical images. To accomplish this, two methods were used to optimize the amount of light able to be captured. The first method was to use an application that would override the manual exposure and aperture settings on the iPhone so we could increase the exposure time of the image. The second method was to take a video of the constellation, then stack the individual individual images of the video into a single image. We then used computer software to analyze the luminosity of the individual astronomical objects in the image.

Location: SIC 207

The Height of Maglevs

Strassman, B, Physics with Algebra & Trigonometry

NevIlle, S, Physics with Algebra & Trigonometry

Magnets have two different poles, north and south. When like poles are facing each other, the magnets are repelled from each other. When deciding on a symposium topic, we found that we were interested in Maglev trains, which are commonly used in Europe and Asia. Maglev trains are so fast and effective because of the lack of friction caused by wheels on conventional trains. We decided to test how the weight of the train impacts the height between the train and the track (the 2 like poles of the magnets). We chose to create a train and track out of Legos. We then placed different weights on top of the train and measured the distance between the two magnets. After testing, we discovered that the relationship between the weight and distance between the magnets is exponentially proportional. The more weight that is added to the train, the smaller the change in height is between the train and the track. In the real world, this could be used to calculate the potential height of the trains when taking the weight of passengers and train into account.

Location: SIC 207

Chroma Variance and Wavelength

Couchman, L, Physics with Algebra & Trigonometry

Stais, M, Physics with Algebra & Trigonometry

Color blindness has long been a topic of research due to the importance that sight plays in our everyday lives, affecting various decisions that could easily affect our quality of life. Color blindness is caused by the lack of one type of color-detecting cone in the retina. Some people are either missing one of the three, or have one or more which does not function, making them colorblind.

We researched how value and chroma of a particular color affect the perceived affect the intensity and wavelength that would be perceived. Looking at gradient of yellow, we collect reflectance data that provided the different wavelengths that each variant would hold. We found that as the saturation decreases, the intensity decreases. Meanwhile, the wavelength remains the same, showing wavelength peaks of various intensity at 550.3 nm, and has a low of 517, with in this chroma variance. This simulates the range that a person would be able to detect a certain amount of chroma.

This study serves to only simulate an aspect of color blindness and explore methods that biologists have used to attempt to better understand color vision sensory experience. Further steps of this project could include, studying different chroma gradient charts, creating a study that would involve test subjects to evaluate if they are color-blind, and creating a chart in which a color-blind person could see the variance.

Location: SIC 207

How Density of A String Affects Sound Transmission Through a Paper Cup Phones

Luehrsen, K, Physics with Algebra & Trigonometry

Madsen, C, Physics with Algebra & Trigonometry

With the invention of cellular devices, it is commonly forgotten that telephones were once hooked up to cables, and that speaking to one another among a far(ish) distance can be very simple: string phones! This is a study on sound transmission through string, and how the density of the string material affects sound level and the quality of the sound. We wanted to study how the physical material of a string will affect how loud and how clear a message is transmitted through a string and executed through a paper cup. To give some context, when we talk, our vocal cords make molecules inside the cup vibrate, causing other molecules to vibrate, creating invisible longitudinal waves, eventually translating into sound once reaching your ear. To test how linear density would affect this process, we assessed nylon string, fishing wire and cotton string. For our qualitative data, we played a song through a speaker in one cup, and asked a volunteer to interpret what they were hearing and rate it. For our quantitative data, we played a song through a speaker, and placed a sound level meter inside of the cup at the other end measuring the reverberation time and level of sound. Our results confirmed our hypothesis that a higher density would result in a higher sound level. Since particles in the air are more spread out than in a solid (a string), they will diminish quickly, before being able to oscillate. This is why using a string (especially a string with a higher density) is much more effective transmitting sound over a larger distance.

Location: SIC 207

Examining Particulates in the Air and How They Interact With Light Rays

Perlman, O, Physics with Algebra & Trigonometry

Press, J, Physics with Algebra & Trigonometry

Zamil, M, Environmental Science

Research, such as studies by Coco Ballantyne, have shown that the colors and vibrancy of sunsets are impacted by particulates in the air. This research is justified by the fact that there are various population densities around the world, affecting the air pollution in each of these places. Our research goal is to determine the impact of air pollution on sunsets, examining both how the path of light is changed by the particulates and how it behaves. We will be measuring air pollution levels using dust particle collector strips which are taped to the side mirror of a car, in addition to taking a time-lapse of the sunsets in order to examine the colors. After analyzing our data we found that the strip from Novato contained 424 particulates and the strip from Panoramic Highway contained 470 particulates, while the strip from Terra Linda contained 1024 particulates (largely due to factors such as cars driving by, strong winds, and pollen from the field of cordgrass). This difference is large considering the short time period we held up the strip for: only 1/6 of an hour at each location. These findings lead us to an important question: do beautiful sunsets come at a cost to the environment?

Location: SIC 207

Building a Xylophone: Pitch, Frequency, Wavelength and Fundamental Frequency

Etlin, A, Physics with Algebra & Trigonometry

Lasher, J, Physics with Algebra & Trigonometry

Musical instruments have long been used as tools to create happiness and bring people together. In researching for this project, we found that instruments like pan flutes, drums, and xylophones can be made using relatively common objects. We ultimately decided on building a xylophone because we felt we could make a high quality instrument that both sounded nice and was able to not only use our prior physics knowledge but could build on it and push the boundaries of what we have learned this year. To build the xylophone, we followed instructions that were already available online about the construction of xylophones. Our xylophone was built from a wood base, electric metal tubing for pipes, and foam placed beneath the pipes to prevent the vibrations from being dampened by the metal vibrating on top of the wood. The key to building homemade instruments is to make sure that they are tuned correctly, something we did by using an equation for predicting the pitch the pipes make due to their length. We followed the instructions in deciding how long our pipes should be, but we were able to calculate which note each pipe was playing using the equation v=fλ. Other applications for the usefulness for our xylophone is to show the practicality of using homemade instruments using minimal money and our physics knowledge. We also hope to leave our instrument with the music program, so our xylophone can create happiness and bring music students together for years to come.

Location: SIC 207

The Relationship Between Spin Rate of a Ball and its Horizontal Trajectory

Friedman, E, Physics with Algebra & Trigonometry

Sternberg, C, Physics with Algebra & Trigonometry

In tennis, when the ball is hit with different spins, it travels with different trajectories and velocities. The Magnus effect states that a spinning ball moving in a direction at an angle to its axis of spin through air or water will curve according to the direction of the spin. Our research question is what is the relationship between spin rate and horizontal distance traveled of a beach ball. We recorded several test runs consisting of dropping a ball about three meters with different spin rates generated by the person dropping the ball. We then used LoggerPro video analysis to determine spin rate and horizontal velocity. We created a Spin Rate vs. Horizontal Velocity graph in LoggerPro. The positive slope of the linear fit of our data points indicates that a higher spin rate of the ball results in a higher horizontal velocity, and thus more horizontal distance covered. This is explained by the Magnus effect stating that the layer of air around the spinning ball will be have a side of lower pressure, sucking the ball in that direction.

Location: SIC 207

An investigation into the process of studying algae

Haase Cox, S, Marin Academy Research Collaborative

Algae is a broad category of simple, non-flowering aquatic plants. When there is an abundance of certain nutrients present in the algae’s environment, they can grow very rapidly, causing an algal bloom. This can become a problem, as some forms of algae produce toxins, a common example of which is domoic acid. This toxin can be transferred to humans and aquatic animals through consumption of contaminated shellfish. Because of this risk of toxic algal blooms, the effects of ocean conditions on algae growth have been studied. However, because many studies use samples of algae taken from the ocean, the effect of individual conditions on the growth cannot be determined, and any correlation extrapolated from this data generally contradicts other studies. In order to isolate and study changes in specific ocean conditions, such as light or temperature, it is necessary to carry out research in the lab instead of collecting samples. This project aims to investigate the process of growing and studying algae in a lab, using the chlorophyte C599, as it is generally considered easy to grow. I followed along with what Maia Perry was doing for her MARC project, and learned the process of transferring a starter culture to other culture tubes, as well as how to use the spectrophotometer to record data on the growth of the algae. I will utilize these basic skills next year when I begin my own experiment on algae.

Location: SIC Upstairs Hub

Potential For Absolute Pitch Learning Based on Age of Musical Initiation and Individual Musical Background

Rudnick, S, Marin Academy Research Collaborative

Absolute pitch has been widely studied, but remains an enigma when it comes to who has it or who can learn it. Some research has lead the scientific community to believe that there may be a genetic factor involved, although it is generally accepted that there is also an aspect of nurture involved with regards t musical education and experience. This study aims to expand on this aspect of nurture, and determine how musical background and age affect baseline absolute pitch aptitude. Musical background refers to what instrument(s) one plays and when one began playing it/them. To test this is a very simple task. First, each participant must fill out a survey. In this survey the participant states their age, what instrument(s) they play, when they began playing it/them, and how they would rate their AP ability from 1-10. Then, in a follow-up session, each participant is played 30 tones on GarageBand, with a ascending and then descending tone in between to erase their pitch memory and hopefully make relative pitch a non factor. In the case that the study is successful, correlations will show up to suggest that instrument, age of musical initiation, and personal AP self-rating have some connection with actual AP ability. Based on the existing data, a few predictions can be made. For example, according to a University of Chicago study, AP is most often found in those who began learning music from ages four to six. This study aims to support assertions like these, and hopefully make a few of its own.

Location: SIC Upstairs Hub

Camvid Semantic Image Segmentation with a Residual UNET

Salesky, N, Marin Academy Research Collaborative

Neural networks are computational models used to process complex computations much faster and more efficiently than humans. Convolutional neural networks (CNN) are one type of neural network commonly used for image classification and object detection. Unlike simple image classification, semantic image segmentation involves classifying every single pixel of an input image as belonging to one of specific classes. In order to “train” a neural network, you need a dataset that the model can be optimized for. Camvid is one such dataset for semantic image segmentation, containing thousands of labelled images taken from the viewpoint of a car dashboard. This project aims to build an image segmentation model that can accurately classify parts of images with the Camvid dataset. More specifically, this model will be a residual UNET created with the PyTorch and FastAI libraries. A UNET is just a more specialized version of a CNN originally created for image segmentation. I trained the model two different times, one with a Resnet34 and one with a Resnet50. The only difference between them is the amount of layers they contain (34 versus 50), and the theory is that in order to make the model more accurate, it should be deeper. This project is significant because of the increasing prevalence of object detection and image segmentation in today’s world, through bioimaging, self-driving cars, and surveillance systems of countries such as China. However, this project also gives me a solid base to build off of next year as I further continue my MARC project.

Location: SIC Upstairs Hub

Sleep Deprivation in High Schoolers

Friedman, S, Marin Academy Research Collaborative

Sleep is a necessity for humans with the required amount of sleep decreasing with age. When a person goes through puberty, their circadian rhythm (the body’s internal process of regulating a person’s sleep and wake cycle), changes; once students reach high school age, their body makes them tired later in the day and wakes them up later in the morning. Due to the combination of the consistency of early school start times, a shift in a person’s circadian rhythm, and activities such as homework or sports, high school students are not getting the amount of sleep required for their age range. Through an anonymous school-wide questionnaire, I have begun to gather data about my classmates to learn more about the role that a student’s grade level (9th, 10th, 11th, or 12th) plays in the amount of sleep they obtain, and how that affects their daily experience. Currently, I have received a total of 85 responses: 27 freshmen, 23 sophomores, 21 juniors, and 12 seniors. So far, I have found that on average, freshmen get the most amount of sleep, followed by seniors. In the future, I plan on getting more data from the remaining 300 students who have not yet taken my questionnaire; this will allow my data to be more accurate.

Location: SIC Upstairs Hub

Testing The Mutagenicity of Juul Fluid Using The Ames Test

Raja, I, Marin Academy Research Collaborative

The sudden resurgence of nicotine popularity on the social and public health scene has left many scientists, researchers, and government officials feeling blindsided or completely unaware of how this will impact the health of the next generation. As this is a relatively recent crisis, there has yet to be comprehensive studies conducted on the long-term or even short term impacts of e-cigarette use. In studies on Juul pods, researchers have found that they contain up to three times the amount of nicotine per milliliter than other popular e-cigarette brands. Additionally, there are various flavoring chemicals in the fluids that demonstrate a cause for concern for many scientists, but this is a question that has not been fully excavated yet in the scientific and clinical world. I have conducted an Ames test on Juul (a popular e-cigarette brand) pod fluid in order to determine its mutagenicity. The Ames Test or Salmonella typhimurium reverse mutation assay is a popularly utilized mutagenicity test which identifies carcinogens, substances, and exposures that can lead to cancer, by using mutagenicity in bacteria, which is high correlation model for mutagenicity in animals. In this experiment, I hope to determine if the fluid in Juul pods have carcinogenic properties that could potentially lead to cancer.

Location: SIC Upstairs Hub

Investigation of Artificial Sweeteners on Lactobacillus acidophilus Fermentation

Hee, C, Marin Academy Research Collaborative

The prevalent epidemic of diabetes and high blood sugar in the United States because of the consumption of an excess of sugar is a serious health issue. One solution to this is instead, consuming artificial sweeteners. However, recent research has shown that artificial sweeteners can alter the growth of bacteria in the microbiome. In this experiment, I examined the effects of artificial sweeteners including Stevia and Sweet and Low, along with the sugars fructose, glucose, and sucrose. These sugars were tested to see their influence on the bacteria Lactobacillus acidophilus, a significant probiotic found naturally in human intestines. This study, based off of a similar study done at the University of Latvia, tests these five sweeteners using a carbohydrate fermentation test with a phenol red broth. The acid production from fermentation and gas production were both observed after the test was complete. The results demonstrate that the Lactobacillus acidophilus was able to ferment the fructose, glucose, and Sweet and Low and wasn’t able to ferment the sucrose. The stevia was able to be partially fermented by the bacteria. There was no gas production from the bacteria in any of the trials. This experiment is a preliminary test that will lead to further research on the effects of artificial sweeteners, including the lesser researched stevia, on the human microbiome.

Location: SIC Upstairs Hub

3D Printed Prothesis Testing

Shilakes, I, Marin Academy Research Collaborative

Prostheses are used by many people in the country and 3D printers are becoming more effective in industrial use. Historically there had been many different ways to make a prosthesis but mainly had been cast. Studies of plastics have gone more into depth and fractology, the study of breaking science, has brought me into a new direction of research and mindset of researching plastics in use(1). The focus of this overall project is creating an affordable and durable prosthesis using HIPS, ABS, Polycarbonate, Flexfill, and Wood full to determine which of the filaments works best provided the desired function. For this presentation, however, only Flexfill will be used to assess the parameters needed for the soft- and hardware to be able to 3D print a working model. A procedural modification that targeted speed and percent fill had to be made in order to enhance the printing process. This improved the printing speed by 45% and addressed a lower extruder temperature of 250°C to 245°C, which was preset for flexible filaments in Prusa. Results have yielded less print error, although the design still needs work. Next steps in the project will be to focus on printing fingers, then the overall design, in PLA ensure the design is stable. Following this, specifics about which filament is best to use regionally on the hand can be better determined.

Location: SIC Upstairs Hub

TEnSOR (TdE StratificatiOn Rf): Novel Machine Learning Classification of Tidal Disruption Events

Moriyama-Gurish, A, Marin Academy Research Collaborative

Black holes present the opportunity to understand the curvature of spacetime. Black holes are difficult to observe due to the inherent strong gravitational effects which not even light can escape. However, observing how blackholes interact with visible matter may provide insight into the detection and property dynamics of massive black holes. Tidal disruption events (TDEs) occur when a star’s path encroaches on the event horizon of a supermassive black hole, such that tidal forces pull the star apart in a process known as “spaghettification”. As a result, TDEs produce energetic jets that are hypothesized locations of high-energy neutrino production. This project presents a new strategy for efficiently classifying TDEs by employing dual machine learning Random Forest classifiers. Trained on the photometric data of ~11,000 events and the spectroscopic data of ~20,000 events, the classifiers analyzed photometric and spectral data independently. The results of the two classifiers were then used to classify the probability that an event is a TDE. The result of this project is a machine learning classifier with a mean accuracy of ~86.5475%. This new classification system will aid in more efficient and accurate classification of TDEs, allowing for greater understanding of supermassive black holes and the creation of galaxies

Location: SIC Upstairs Hub