2017 ISSUE
TAU
SCIENCE MAGAZINE A SCIENCE LOBBY The state of science in our world
TAU SCIENCE MAGAZINE A MONTGOMERY HIGH SCHOOL STEM BOARD PUBLICATION TAUMAGAZINE.COM • FACEBOOK.COM/TAUSCIENCEMAGAZINE
GENETIC MANIPULATION
A look into the future of genetic remodeling and the startling ramifications
Table of Contents 3 A Science Lobby 4 Real Role Models for High School STEAM Students 5 Elephas maximus and Loxodonta africana 6 Girls Who Code 8 Monty Hacks 10 Beautiful Bioluminescence 12 Recent Advances in the Proof of the Twin Primes Conjecture 12 Do You Really Remember? 14 Genetic Manipulation 18 Sugar, how sweet is it really? 20 Romidepsin 22 GENE Silencing: siRNA 24 Together Ensnared in the World of TRAPPIST-1 25 The Ocean Above Us 26 Understanding LEDs, and then Using LEDs to Approximate Planck’s Constant in a DIY Experiment 1
Acknowledgements Editor in Chief Vijay Srivastava Editors Jenny Huang and Annie Li Advisor Jason Sullivan
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A Science Lobby We are living in a time of great adversity. The political atmosphere in this country is charged, with so many issues polarizing the nation. It is hard to believe that our country has changed so much in a short period of time. In light of recent statements and actions taken by the government, it is important to understand that there is a need for something in our government, scientists. While it would be nice to have more congressmen and congresswomen who are scientists, a different approach can be used, a group of science lobbyists. Having science lobbyists involved in the government would make our nation far more progressive and allow us to solve key issues that plague this country and the world. Take climate change, for example. There are political factions who reject the existence of climate change and believe that it is something fictional. However, scientific research proves that climate change does indeed exist. Thus, having a “scientific lobby� would make this a lot better since these individuals can present studies, unbiased sources of information, to demonstrate the harmful effects of climate change. This, in turn, would, hopefully, change the opinions of our statesmen and motivate them to take action. In addition to climate change, the topic of abortion has also polarized this nation. Some groups believe that it is wrong to terminate the life of an unborn baby, while others argue that it is not a human being whose life you are terminating. Once again, we have individuals arguing about this issue with limited information. Presenting research would help these individuals understand the topic better and help them address it. The point is that politics and science go hand in hand in some of the key issues that affect this nation. It is our job as young scientists, to advocate for the involvement of science in our government. Remember that arguments can be disputed, but facts cannot.
Aneesh Atri, Grade 10
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Real Role Models For High School STEAM Students Iccha Singh
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My name is Iccha Singh, and I am a freshman at the Montgomery High School. I am a member of the Montgomery High School’s S.T.E.M. Board and have been running Techsters, a tech club at the Montgomery Upper Middle School since 6th grade. My mission is to: Empower girls to speak up, lead, and get involved in the S.T.E.A.M. field. Keeping this in mind, I organized and hosted a live video chat session with women working at the National Aeronautics and Space Administration (NASA) in an attempt to inspire girls and my peers to hear firsthand what it takes to work and become a part of a nationally recognized organization such as NASA. I believe it is very important to have female role models to look up to in the STEAM field. According to Forbes magazine, “Tech is about people, not technology”. Then why are only 17.9% of undergraduate females receiving a bachelor degree in Computer Science, 25% women in the CS workforce, and 18% of Computer and Information Sciences women? Why is it that 13.33% of the engineers at Facebook are female, 8.26% at Yelp, and 12.75% at Pinterest? Why are only 15% of women in executive positions at their STEAM job? Why does raising a child set a woman’s salary back by 4%? Why does it add up to women making up way under half of the STEAM workforce? Why? I had linked up the projector, my computer was ready, the connection was strong, and the audience had settled in. Now was the big moment, the time to make the call. I had had a dry run a day earlier but once again I felt the same nervousness and childlike excitement. After all, this was NASA, an organization that we have all known since we were young scientists marveling over astronauts who went to the moon! On
one hand NASA provides us with an “out of this world” experience but on the other hand, I was about to talk to real women, embarking on their real journeys on how they got to work at NASA. This was and still is a “WOW” moment for me! The panelists included the Manager of the Engineering and Science Department at NASA, Project Coordinator, a Communications Lead, a Technology Support, and Engineers who hold leading roles. The diversity shed light on the fact that big organizations such as NASA don’t only look for people with STEAM backgrounds but all backgrounds of study. NASA needs good communicators and organizers as much as they need stellar computer scientists. When I mentioned “real women” before I wanted to stress how authentic these women and their backgrounds were. They were not 4.0 GPA students who went to Ivy Leagues and were top of their classes. Quite the contrary, they didn’t all have perfect scores or top notch education, they didn’t even overload on APs. They however never lost their reverence to learn. They were always eager to challenge themselves, not scared to ask questions, and didn’t take the easier route to avoid failure. These women embraced it all! While enjoying extra-curricular activities, participating in community service, and focusing on academics, these women were well-rounded individuals who used their passion to keep learning as their motivation to get to where they are today. During the chat, we were able to discuss the implicit bias that is present in this male dominated field. It was revealed by a data analyst working at the Marshall Space Flight Center that “80% of the time, the name ‘Jack’ will be more favorable against ‘Jill’ despite the fact that they both have the exact same resumes”. The Manag-
er of the Engineering and Science Department elaborated NASA’s focus on diversity, inclusion, anti-harassment and equal employment opportunity. However, she also touched upon NASA being a government run organization meaning that NASA may be an equal community for all, but situations similar to Jack and Jill above occur mostly outside of the government controlled domain. To our surprise, the panelists were encouraging us to “Not be afraid of failure.”, “Keep asking questions.”, and “Continue to learn.” This is because they knew (from their experience) that perseverance through the tough times is what stands out and propels you further. These women have overcome many of the hurdles that females encounter when working in the STEAM workforce, but they still smile when thinking about the amazing work that they are doing. Their enthusiasm for their work is what motivates them, and continues to pull them through the most adverse of times. “Being happy with what you do”, is one of the biggest takeaways from this event! I asked the women working at NASA what they think would’ve encouraged them to get in-
volved with STEAM at an earlier age, and their response was: “Things like this!” They firmly believed that exposure was key as well as following other inspirational women all supporting them to get involved and inspiring them to reach for the stars! Undeniably there is an issue with women in the tech field as being underfunded and sexually harassed, but I want to continue to raise awareness amongst girls and I urge my peers to look at the statistics for themselves. Currently, there are only 25% of all women in the computing workforce, and if this continues, in 2024 there is expected to be 1.1 million computing-related jobs that remain unfilled. I believe this can change. We can make a difference! Let’s speak up, let’s tinker, let’s encourage one another, and let’s never give up so we can seal the leaky pipeline, add diversity, and gain gender neutrality in the STEAM field. Let’s strive to become the role models for the next generation of pioneering women and support each others’ journeys in doing so! Iccha Singh, Grade 9
Elephas maximus and Loxodonta africana Sketches of two well known elephant species Cristina Castro Lopez, Grade 11
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Two-thirds of girls in middle school are interested in pursuing a career in computer science. In college however, only 4% of girls choose a major in computing. Girls Who Code aims to close the gender gap in computer science by offering a free seven-week program to girls who are juniors and seniors in high school. This past summer, I attended Girls Who Code Verizon at NJIT in Newark, New Jersey. Through the program, I learned a total of five different programming languages and developed a final project that helped children in developing countries. Prior to attending this summer program, I had only taken an online Java course. I was worried that I lacked the knowledge other girls had. Contrary to my expectations, the teachers and teaching aides actually expected that most of the girls had little to no experience in coding! The program lasted seven weeks in total, and a new coding language was taught each week with the exception of the final two weeks. During week one, we focused on Scratch, a program that teaches beginners how to code using drag and drop blocks. It served as a good introductory programming language, since we were able to learn the basics of programming without actually writing any code. During the first week, we built programs like Paddle Ball and Jukeboxes in groups. Science Olympiad also uses the same Scratch program in one of their events, Game On. After learning the coding basics, we were taught Python in week 2, which was the first formal computer language we learned. We began with a simple “Hello World” program, meaning that we type the line print(“Hello World!”) into a computer application called Sublime and the computer was then instructed to display the same words. This line is usually one of the first things beginners type when they embark on coding. Later in the week, we used Python to make a Mad Libs game as well as a creative yet complex Text Adventure game that we presented to our classmates. In the following weeks, we delved more into Python through learning Pygame and Object-Oriented Programming before working
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on Robotics with Arduinos and Web Development. During these weeks, we experimented by making side scroller games that were similar to games on websites or apps. We also learned a bit of Physics as we had to learn the difference between concepts like parallel and series when using circuits in Robotics. We also had assignments to make our robot play songs like the Harry Potter theme song and made it dance to the Cha Cha slide. In the fifth week, we learned Web Development, which included HTML and CSS. In order to enhance our websites, however, the teacher taught us languages like Javascript, and showed us how to use Bootstrap and APIs to add unique features. Bootstrap has a multitude of design templates that adds different user interfaces, such as a navigational bar or carousel of images, to a plain web page. Similarly, APIs can embed features like Google maps or Youtube videos onto a site. In the final two weeks of the program, students formed groups of 2 or 3 to build a final project based on a topic they were passionate about. For instance, one of my friends had a family restaurant. She came up an idea to help attract more customers to the restaurant by developing an online food ordering system called Trofi. Trofi lists all the ingredients in a dish so that a consumer may check to see if there is anything he or she is allergic to. For my final project, my group and I built a website that connected students in developing countries to mentors in STEM, who taught them how to code. During these final two weeks, I not only applied the concepts and knowledge I learned in class, but also learned how to use Github and Heroku to make my website live, as well as PHP, a programming language, and MySQL to create databases behind the website. Throughout this experience, I was able to develop my skills in computer science in a supportive environment. In a society where technology is everywhere, coding is a useful skill that allows people to accomplish a myriad of actions from building robots to developing software. Elizabeth Song, Grade 11
public class TAU { Article es = New Article(); es.setTitle(“girls_who_code); es.setAuthor(“elizabeth_song”); System.out.println(es.getTitle); System.out.println(es.getAuthor); }
Girls Who Code Elizabeth Song
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Monty Hacks
What does it mean to hack? For Montgomery High School, that word was redefined through its new event, MontyHacks. On Saturday, April 22nd, Montgomery High School held its own high school hackAathon for the first time in history. Co-hosted by the MHS Computer Science Club and the Young Entrepreneurs Club of NJ, and with over 100 students participating, volunteering, and mentoring, it was truly an exciting experience.
Far from being a competition to breach sensitive data (“hackathon” is a misnomer), this unique day-long event gave participating students the opportunity to showcase their programming skills, and provided learning opportunities for both complete beginners and experienced coders. A hackathon is not only
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a event where people learn, meet new friends, and share their passions, but also a place where students from completely different backgrounds come together to build and create entirely new products and platforms to solve problems they see in society. This promotion of the inventive spirit is what sets MontyHacks apart from any other event held in the school. That weekend, Montgomery High School transformed into a hub for students from all over the state to innovate and impact the community. Throughout the day, students collaborated to build and create new projects, all from scratch. The high school hosted representatives from Microsoft, MongoDB, and DataDog, who gave talks that combined the technical and inspirational to participants at the opening ceremony. With mentoring by Princeton University students, workshops, hardware, and guidance, all provided for free, students were able to build whole platforms within a mere 12 hours and present them to other participants at the end of the day. A total of 23 unique, socially impactful projects were presented at MontyHacks, varying from electroencephalography sensors to solar-powered charging devices. After a judging process, winning participants were also awarded with tech prizes like Amazon Echo Dots and Gear VRs to allow them to further explore the computer science field. By the end of the hackathon, participants had played the role of a student, designer, project manager, engineer, and
entrepreneur, making for a truly unforgettable experience. In the beginning, hackathons were usually only run by large companies and tech organizations. Over time, they became more prevalent in top universities like the University of Pennsylvania, Princeton University, and the University of Michigan. By launching an event like MontyHacks, Montgomery High School is taking a pioneering step in promoting STEM education, as it is one of the first high schools in the state to embrace the hackathon culture and spirit. MontyHacks was a huge success, and could not have been made possible without help from the school administration, its organizers and team, and its volunteers. We would like to extend our thanks to Ms. Nancy Gartenberg, Mr. Scott Pachuta and Mr. Jason Sullivan, as well as Kyle Li, Christine Cirullo, Justin Chung, Evelyn Shiang
and Katherine Yoon, for their invaluable contributions to the event. And of course, we would like to thank our judges, Mrs. Avis Yates Rivers, Mr. Jason Sullivan, and Mr. Victor Zhou. Finally, we would like to thank our participants for making the hackathon everything we hoped it would be, and more. So what’s next? MontyHacks will be back for its second iteration next winter, and will become a full-length, 24 hour hackathon. It will be of even larger scale, featuring bigger and better activities, sponsors, and prizes. We can’t wait to see you there!
Ivan Chau, Julia Guo, Niva Sivakumar, Grades 11 and 10
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Beautiful Bioluminescence: GFP and the Aequorea Jellyfish Sruti Cheruvu
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You’ve probably heard of bioluminescence before - a series of reactions that causes living organisms to emit different colors of light. If you ever went to the aquarium, you might have seen bioluminescence in action when you saw jellyfish occasionally glow blue or purple. Are such organisms rare? Not necessarily. The next time you see fireflies, take note that every “flash” you see is an example of bioluminescence. As you will see later on, this phenomenon is not mere ornamentation. One of my favorite examples of bioluminescence in nature is the use of the green fluorescent protein (GFP) in the Aequorea victoria species of jellyfish. Although the exact reason is not known yet, this species, and many others, may have evolved (or adopted) GFP proteins as a means of defense against predators. This is especially useful since jellyfish do not have muscles and cannot escape quickly from predators on their own accord. Jellyfish, like most cnidaria, have some disadvantages compared to other forms of marine life. Although they are not sessile, they do not contain skeletal muscles in their tentacles, so they have to rely on on water currents to carry them from one place to another. This makes it difficult to escape from predators because jellyfish cannot voluntarily control their tentacles and give themselves enough time to escape and swim faster. Also, because the jellyfish does not have a brain but a “nerve net” instead, it is not consciously aware of its surroundings and will thus only react to a predator that comes into contact with it. At this point, the jellyfish uses a technique called “burglar alarm” when predators come into contact with it. When the predator brushes against the jellyfish, this causes the striated muscles to stimulate and produce Ca2+ ions. These Ca2+ ions go on to bind with the protein complex aequorin, which then produces blue light. This blue light in turn is used to cause the green fluorescent protein to go into its excited state. This protein will go into its ground state by releasing green photons. This causes the Aequorea victoria to emit small bits of green light around the end of its “umbrella.” The purpose of this defense mechanism is to attract anything that could get the predator away from the jellyfish. One such distraction is something that could
potentially eat the jellyfish’s predator. This idea of animals using bioluminescence to make their own predators into targets is very clever. Although these jellyfish have utilized GFP as a means of defense for a long time, it is only recently that humans have been able to use it for their own purposes. Scientists have been able to harvest the gene that produces GFP and incorporate it into the plasmids of bacteria. They then have been able to induce these bacteria so that they could produce GFP. These bacteria are multiplied, and then the GFP is extracted. So far, this protein has been used as a reporter gene that can be expressed simultaneously with another gene that is being studied. By observing a green glow in cells, scientists can use that to study the nature of certain genes. This has further applications which translate into studying cell biology, and conducting cancer research. On the fun side, the GFP gene has been added to the DNA of some zebrafish, which means that people can now have their own bioluminescent pets.
Sruti Cheruvu, Grade 12
protopedia.org
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Recent Advances in the Proof of the Twin Primes Conjecture
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You’ve probably heard of twin primes. If you haven’t, they’re simply a pair of primes with a difference of 2, for example 3 and 5. The twinprime conjecture states that there are infinite number of pairs of twin primes. It’s a pretty famous conjecture in number theory, and perhaps even one of the simplest, and yet one that has remained unsolved for years. When you think about it, it’s pretty easy to believe that the conjecture is true. Wikipedia gives many of the starting pairs of twin primes, (3, 5), (5, 7), (11, 13), (17, 19), (29, 31), (41, 43), (59, 61), (71, 73), (101, 103), (107, 109), (137, 139), and there seems no reason to believe that this wouldn’t continue forever. Unfortunately, this does not point in any direction to how the proof of the conjecture is supposed to go. In fact, until these past few years, much progress at all had not been made. Sure, there were (lots of) attempts, but nothing really getting the conjecture closer to its proof. Then, in April 2013, Yitang Zhang, a lecturer at the University of New Hampshire, submitted an article to a magazine (published in part by Princeton University) detailing his proof for the first finite bound for gaps between infinitely many primes. If a number k denotes the possible difference between infinitely many primes, Zhang’s work essentially proved that a k less than or equal to 70,000,000 existed. An important distinction to make here is that the value of k had not been found, but merely the existence of it was. 70,000,000 is a pretty large number, and it’s easy to want to disregard Zhang’s finding as something relatively useless…if you’re not a number theorist.
Zhang’s work actually ended up generating quite a lot of interest in the problem and in November of 2013, it was found that k was less than or equal to 606, a number much less than 70 million! In April 2014, it was proved that k was less than or equal to 246. Finally, using another conjecture and its generalization and assuming that it is true, the bounds can be reduced even further to 6. Of course, this brings us back to our original problem. We’re still not at k = 2, but we’re definitely closer. So where to go from here? After k = 2, maybe there are more generalized cases that can be proven next. Instead of twin primes, with a difference of 2, we could try cousin primes next (k = 4), or even sexy primes (this is an actual thing, k = 6). The point is, there are many, many “k-tuples” that are still to be explored. Yitang Zhang and the other mathematicians who built on his discoveries only touched the tip of the iceberg.
Niva Sivakumar, Grade 10
Do You Really Remember? There is a famous saying, “Memories make us.” The reasoning behind this statement is without recollecting simple facts about our lives, humans could not function. As renowned American cognitive psychologist Robert Sternberg once said, “Memory is the means by which we draw on our past experiences in order to use this information in the present,” while using some memories procedurally by processing them in the hippocampus (the center of emotion and memory in the brain), other memories are sent to different areas of the cerebral cortex for permanent storage. These two types of memories can be classified as long term and short term, and at the cellular level, the differences between these two types of memories are expressed through the changes to the structures
and functions of the neurons storing the memories. A short-term memory’s conversion to longterm memory requires the passage of time and a healthy cerebral cortex. In fact, researchers now know that memories must pass through this area first in order to be encoded because individuals with brain damage in this area are unable to retain new information for a long time. When talking about memories, a familiar part of the cerebral cortex known as the prefrontal cortex is thought to be the brain’s central executive because it directs thought processes such as abstract thought as well as decision making and maintains emotional control. Without a proper storage of memories, regardless of short or long term, the prefrontal cortex cannot function, therefore making the person more impulsive and animalistic. Repeated actions cause a phenomenon to occur in the brain, and this phenomenon is commonly known as the creation of muscle memory. A task, with repetition, can be turned into an automatic process. However, sometimes the task itself is not intentionally learned through repetition but is learned through habit or genetics. Broca’s area, an area in the frontal section or lobe of the cerebral cortex is responsible for controlling the muscle movements needed for speech. Damage to this area might leave the person unable to make the muscle movements needed for speech. Similarly, the Wernicke’s area, located in the temporal lobe(which is responsible for processing sound), interprets both written and spoken speech. Damage to this area would affect the ability to understand language, and speech would sound fluent but lack the proper syntax and grammatical structure needed for meaningful communication. Speech and language are aspects of life that come with growth, therefore showing how important the use of long-term memories is in relation to communication. Now, research is showing that it is fairly easy to take advantage of our memory. Elizabeth Loftus, a cognitive psychologist and expert on human memory, found that simply changing one word in a question can distort a memory. In one experiment, Loftus had participants view a film of a car crash before asking them about what they watched. They were asked “How fast
were the cars going when they hit each other,” or “How fast were the cars going when they smashed into each other.” At a different time, Loftus asked whether or not there was broken glass at the scene of the accident. Those participants that heard the word “smashed” were actually more than twice as likely to remember seeing broken glass than those who heard the word “hit”, despite the fact that there was no broken glass in the accident. Ultimately, this all just shows that sometimes, our memories can be unreliable. They can misattribute the source from where the memory was created, a face to the wrong context, or even an imagined event as reality! Discovering how easily memories are changed points out to us that part of ourselves is fabricated or false in some way, but that’s just how our brain works! As pioneering psychologist William James proposed, memories can be carved from both reality and our dreams. “Most people, probably, are in doubt about certain matters ascribed to their past. They may have seen them, may have said them, done them, or they may only have dreamed or imagined they did so.” –William James Anirudh Maddali, Grade 10 Sources: https://blogs.scientificamerican.com/guestblog/how-long-will-a-lie-last-new-study-findsthat-false-memories-linger-for-years/ http s : / / w w w. re s e arc hg at e . n e t / pu b l i c a tion/252325755_Creating_a_False_Memory_ in_the_Hippocampus http://www.spring.org.uk/2008/02/how-memories-are-distorted-and-invented.php https://www.psycholog ytoday.com/blog/ talking-apes/201603/why-you-cant-trust-yourmemory-anything
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Genetic Manipulation Harry Feng
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In a plain, red brick apartment sits a guard dog, astutely fulfilling its duty. It surveys the surroundings as if analyzing each passerby’s hidden thoughts, ready to act against any hint of malicious intent. Suddenly a black ski-masked figure scrambles out from the apartment window. Without hesitation, the dog dashes forth in an attempt to stop the burglar. “Woof! Put your hands up or I’ll shoot!” the dog barks, raising a miniature pistol in an expert-like manner, aimed straight at the intruder. Unexpectedly, this could be possible in our future as scientists are developing tools that can manipulate DNA, which could develop the ability to combine animal and human into one organism. And yet this proposes the question as to whether it is morally permissible to fabricate someone to human imagination. Where can a scientist draw the line as to what work this new tool will do? An accumulation of recent discoveries has led to the development of genome editing; at one forefront of this technology is CRISPR (i.e. Clustered Regularly Interspaced Short Palindromic Repeats), a tool that is capable of removing specific genetic sequences within DNA and replacing them with different ones. Originally discovered from bacteria, CRISPR is a system devised of two important molecules: gRNA and CAS9. The gRNA itself is composed of a crRNA and a tracerRNA. The first component runs antiparallel to the DNA strand opposite the target strand. Then the second component binds itself to the 3’ end of the crRNA and acts as scaffolding for CAS9. Thus, the start of the gRNA is the 5’ end that matches the 3’ end of the DNA. Normally, this RNA will have 20+ base pairs that act as a guiding sequence for the gRNA to attach itself to a specific section of DNA. Moreover, this guiding sequence should contribute to 40-80% of the content in the gRNA. The second molecule, CAS9, is an enzyme that acts as the scissors and cuts where the gRNA signals it too. Thus, this guidance RNA can be preprogrammed by geneticists to attach to the correct section of the genome. After the sequence has been cut, a mutation will then occur to fix the gap— albeit not perfectly. CRISPR could also be designed to replace that space with another sequence so that the DNA can be remolded into its desired
sequence. CRISPR overall paves the way for permanent modification of DNA through a simple and precise method. Opposition towards research in this area has cited ethics and hidden dangers as a reason to place genome manipulation under a moratorium, or temporary prohibition. One major factor of the general wariness towards this technology is its current limitations, specifically the lack of precision in the gRNA design. Sometimes the guidance molecule may attach to the wrong section of the genome causing untold damage to the subject who is undergoing the operation if it was a crucial gene. Another fear is the belief that this technology can lead to consequential catastrophes in the ecosystem due to the development of unnatural creatures or animal character traits. The Earth has its own natural system of evolution that can allow species to adapt to changes in the environment; however, a too drastic change can exceed the ecosystem’s ability to change and can cause selected species to decline in population. As more niches in an ecosystem are left unfulfilled, species will begin to go extinct causing the affected area to become permanently damaged. A third social problem is a greater gap amongst the rich and poor. This is cited through the creation of genetically-modified babies, coined “designer babies.” These are specifically enhanced to have specific features, including eye color, muscle mass, bone strength, height, hair color, and accurate vision. Yet, due to the expensive costs of gene editing, critics believe that only the wealthy class could afford to indulge in this activity. In contrast, the lower class would only be able to dream of such fantasies while raising regular, unenhanced babies. After these two groups of kids are born, one will have a greater advantage over the other in all the traits that they share—creating superiority for the genetically empowered and inferiority for the remainder. Overall, the situation trickles down into an increased disparity both socially, physically, and mentally between the two ends of the classes. Critics continue by describing a pattern of increasing distance as the “designer babies,” become enhanced more and more, away from their original statuses amongst the plebeian infants. Essentially, the general consensus of ar-
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guments against genetic editing is based on an irrational fear of the unknown. But critics must ask themselves whether it is enough to reject this technology purely on that basis. Is there a greater inherent conflict of unrestricted DNA manipulation? In contrast to those critics, other people are wholly supportive of using CRISPR to create a whole new realm of medical ingenuity. Including new species and hybrids under the label of medical research, groups of scientists are currently working on human embryos, testing the possible capabilities of the genetic editing technology. This has led to the implantation of human DNA within a pig embryo. The group, in that case, wishes to develop human organs in animals for future organ transplants—currently, there is a massive need for these kinds of operations. For the majority of supporters, they believe in the use of this technology for not only, as previously mentioned, hereditary diseases, but also for therapy of mental conditions. Connecting to the path of behavioral genetic psychology, psychologists and the like have found that certain genes may be the root of some mental conditions such as depression. Thus, there could also be a utility for genetic editing for therapeutic reasons. An alternative application is its use towards people who have hereditary diseases, giving them the chance to be cured straight at the root of the problem through the alteration of the malformed gene sequences. This holds untold potential, as men and women suffering from muscular dystrophy and other irregularities can truly be given back the full freedoms of the human body. In a related sphere of reasoning are those of grand thinkers, who choose to imagine the realm of past species, as well as, future ones. Some people accommodate the possibility of culminating scientific efforts into the recreation of dinosaurs or other creatures of majestic magnitude like the unicorn. In reality, this remains in the domain of imagination as the genetic editing technology has not reached this point of power, but the possibility still hangs in the air. However, such people must also think as to whether this development might have implications that are on a grander scale of values. Overall, the territory that genome editing
crosses is not one that should be entirely feared, but should still be tread cautiously. For its use may have detrimental effects when done wrong and positive ones when applied correctly; however, the foundational conflict that neither side is able to see is the matter of free will. Though genome editing can create abominations—part human and part animal—the focus should be on whether individuals have the free will to choose for themselves the form they wish to be given. Can humans deliberately break the line of free will and disturb the natural integrity of a newborn baby? Assume perhaps, a man born with a shell, he had no say in the matter, nor did a woman with enhanced strength. Essentially, these people could not determine their own body’s form or structure. Thus, scientists must decide whether they can breach the hidden contract of human will, at risk of usurping the integrity of the individual. One solution brings together the progressive mindset of scientific ingenuity while maintaining the limitations of humane practice. Conceptualized as the fine line of moral justification, scientists are free to break an individual’s free will as long as they maintain their human integrity and the change is deemed beneficial by the majority of the recipients. Such a rule would allow for “designer babies,” and the hereditary disease cures but, in turn, exclude the creation of human hybrids. The rationale behind this is derived from normal human motive. Generally, people agree to pursue the closest they can be to a “perfect,” human, whether it’s through wealth, intelligence, or physical attributes (hence, the allowance for genetically enhanced humans or disease free ones). Though they are unable to decide whether they themselves want the modification, it’s unlikely that more than a few would disagree with them. If a man could choose either to live with glasses or to receive a genetically enhanced vision, most likely he will choose the latter. This same line of reasoning can be applied to the vast population of future subjects, including other modifications. The previously mentioned action remains within the realm of human integrity because enhanced eyesight has a smaller impact on the individual than more eyes. Although an individual may see with more clarity, the detriments would outweigh the benefits because
their facial features would limit their biological fitness—ability to reproduce—in a society that labels them a monster. Essentially, humans have a free will that can only be breached when the change keeps the human’s integrity and is beneficial for the individual. While this may seem complete, there are still questions as to how exactly would the necessary level of positive effects be measured to deem a genetic modification beneficial. In this case, it is most plausible to measure the potential of current technologies. One such example is the development of virtual reality for video games. This line of research is practice directed towards full immersion of the participant in the activity or reality that is being simulated. Ultimately, future development could result in the creation of mental and physical immersion that completely simulates a situation, and in doing so, allows people to experience other worldly interactions. Hence, this technique could be applied to voluntary test subjects who would live a virtual life equipped with specific mutations to their bodies. These variations could range from increased bone strength or any other modifications, all of which would be tested in the simulated arena for practicality and favorability. Afterward, scientists would be able to use the input of the subjects to deem a trait beneficial enough to be applied to the public or not. In addition, genetic editing itself has only just barely passed the early stages of development. Thus, both genetic editing and full immersion technology can potentially collaborate for the experimentation of mutation effects. Ultimately, genetic editing is a tool that can be used in breaking an individual’s free will as only a byproduct of being favorable while maintaining human integrity. It too must be applied only with wisdom and a guided morality just like the many technological marvels before it.
Harry Feng, Grade 11
Works Cited Begley, Sharon. “Scientists Unveil the ‘Most Clever CRISPR Gadget’ so Far.” STAT, 9 Aug. 2016, www.statnews.com/2016/04/20/clever-crispr-advance-unveiled/. “Broad Institute.” Questions and Answers about CRISPR | Broad Institute, www.broadinstitute.org/whatbroad/areas-focus/project-spotlight/questions-and-answers-about-crispr. Carroll, Dana, and R. Alta Charo. “The Societal Opportunities and Challenges of Genome Editing.” Genome Biology, genomebiology.biomedcentral.com/articles/10.1186/s13059-015-0812-0. “CGS : About Human Germline Gene Editing.” CGS : About Human Germline Gene Editing, www.geneticsandsociety.org/article.php?id=8711. “Genome Editing: What Does It Mean for Patients?” Genetic Alliance UK, www.geneticalliance.org.uk/ourwork/medical-research/genome-editing-what-does-itmean-for-patients/. Kaiser, Jocelyn. “The Gene Editor CRISPR Won’t Fully Fix Sick People Anytime Soon. Here’s Why.” Science | AAAS, 5 May 2016, www.sciencemag.org/ news/2016/05/gene-editor-crispr-won-t-fully-fix-sickpeople-anytime-soon-here-s-why. “Knowledge Base.” Knowledge Base | ABM Inc. N.p., n.d. Web. 14 Apr. 2017. <https://www.abmgood.com/ marketing/knowledge_base.php>. Stein, Rob. “Breaking Taboo, Swedish Scientist Seeks To Edit DNA Of Healthy Human Embryos.” NPR, NPR, www. npr.org/sections/health-shots/2016/09/22/494591738/ breaking-taboo-swedish-scientist-seeks-to-edit-dnaof-healthy-human-embryos. Stein, Rob. “In Search For Cures, Scientists Create Embryos That Are Both Animal And Human.” NPR, NPR, www. npr.org/sections/health-shots/2016/05/18/478212837/ in-search-for-cures-scientists-create-embryos-that-areboth-animal-and-human. Stein, Rob. “Scientists Debate How Far To Go In Editing Human Genes.” NPR, NPR, www.npr.org/sections/ health-shots/2015/12/03/458212497/scientists-debatehow-far-to-go-in-editing-human-genes. Stein, Rob. “Scientists Urge Temporary Moratorium On Human Genome Edits.” NPR, NPR, www.npr. org/sections/health-shots/2015/03/20/394311141/scientists-urge-temporary-moratorium-on-human-genome-edits. Sternberg, Sam. “How Will ‘Cut And Paste’ Technology Rewrite Our DNA?” NPR, NPR, www.npr. org/2016/07/15/485706102/how-will-cut-and-pastetechnology-rewrite-our-dna. “What Is CRISPR-Cas9?” Facts, The Public Engagement Team at the Wellcome Genome Campus, 7 Nov. 2016, www.yourgenome.org/facts/what-is-crispr-cas9. Wucherpfennig, Julia. “Understanding Genetics.” Understanding Genetics, genetics.thetech.org/ask-a-geneticist/making-viruses-attack-other-viruses.
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Sugar, how sweet is it really? Yesh Datar Sugar is a staple in the American diet. It’s ubiquitous in our food, finding itself in everything from fruits to home-cooked meals, baked goods, and convenience foods. Out of the millions of food items in America, over 80% of them contain added sugars, underhandedly labeled with creative names like dextrose, brown sugar, sucrose, cane sugar, and corn syrup to avoid any real concern. If we aren’t careful, any variation of sugar can quickly develop from an innocuous addition to our food to an insidious burden on our bodies. The nature of sugar needs to be looked at more critically.
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“One of the leading causes of obesity is the misbelief that, when it comes to juice, ‘100%’ means ‘sugar-free.” - Mokokoma Mokhonoana Yes, sugar is a necessary part of our diet, but only certain kinds and in moderation. Although our tongues can’t distinguish between types of sugars, our bodies can. Sugar is a category of food referred to as “carbs” or carbohydrates. To be simple, sugar has two monosaccharide subcategories called glucose and fructose, and these sugars are processed by and transported to the liver.
Glucose is the body’s preferred form of sugar, commonly found in bread, milk, legumes, and grains. Glucose is preferred by the body because its metabolic pathway activates insulin and allows the liver to process it and then allows the body’s cells to utilize any excess glucose. Glucose is the purer and efficient form of carb energy transport. Fructose, on the other hand, is regrettably like the evil counterpart of sugar which we need to be more aware of. Fructose is found mostly in candy, added sugars, and beverages and is harder for the body to process. Fructose has its own metabolic pathway that doesn’t immediately activate insulin and remains stagnant in the liver’s digestive cycle. Fructose is lipogenic, or fat-producing, behaving more like a vestigial fat in the body than a carb source of energy. It’s a predominant cause of visceral fat, or “belly fat”, easily manifesting itself on those guilty of over consumption of junk food and fructose derivatives. Sugar’s effect on the body, especially in excess or that of fructose, cannot be disregarded. Sugar’s toxic effects are far too often seen in American society because of our poor eating habits founded on convenience and unawareness. Our neglect towards sugar consumption is a primary cause of metabolic syndrome (dysfunctional food-processing), diabetes (ineffective sugar regulation), liver damage, heart disease, and obesity. “Everybody’s got their poison, and mine is sugar” -Derrick Rose, basketball star Can’t you just avoid sugar? Well, no. Unlike all other flavor stimulants, sugar not only oppresses our metabolism but also holds a terrifying grasp on our most powerful organ: our brains. As a person who has experimented with sugar consumption, swearing off sugar for four weeks, I can say the desire for sugar barely subsided, rather it became more habitual to check food labels and stay away from consuming sugar. A countless number of research papers has concluded that sugar is as addictive as opioids and alcohol because it triggers similar dopamine
responses in the brain. For example, if I were to eat broccoli for weeks on end, eventually my satisfaction (measured in dopamine release in the reward center of my brain) would level out. What’s alarming about sugar, however, is the brain’s unduly response to it. Unlike the broccoli case, the body has no leveling off effect with sugar, the more we eat, the more our tolerance grows, and the exponentially more dopamine needs to be released to satisfy us; we never get bored of sugar. Unfortunately, sugar’s manipulation of the brain doesn’t end there. Overconsumption of sugar also influences the receptor-binding hormone leptin, the body’s way of knowing when it’s full. Sugar inhibits leptin binding ability, allowing hunger-stimulating neurotransmitters to continue deceiving the body into thinking it’s still hungry. Because of sugar’s effects on the brain, many of our problems with sugars are catalyzed. We eat nearly three times the National Institute of Health’s recommended daily value of sugar (92 grams as opposed to 32g and 20g for adult males and females, respectively!). We’ve also been rewired because of sugar’s addictive properties to crave sugar in our diets, only worsening our problems. “A spoonful of sugar helps the medicine go down!”-Mary Poppins. Sure, but at what cost? Oh right... obesity, diabetes, heart disease, etc. What are we curing here again? The past presidency saw great bounds in dietary and consumer research and education. But with the onset of new political focuses and government regulations, concern over changing the American diet and future health may fall by the wayside. Already there have been huge proposed budget cuts to national research institutions in medicine and health. So it is a plea, that even if public concern falls, we stay cognizant as individuals of what we consume and how much we do. Don’t fall back to sugary convenience foods, rather search for the right foods and make the right choices. The choices we make now will influence and teach our posterity how to eat well and stay healthy. Yesh Datar, Grade 12
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Romidepsin Imagine if an arsonist had set fire to the local firehouse. How can anyone come to the rescue when the very equipment required for the fight is set ablaze? This is exactly the challenge researchers face with HIV. With formidable viral fitness, HIV has evolved to target cells of the immune system, attacking our body’s emergency response team serving to fight off invading organisms. These immune cells—macrophages, dendritic cells, and T cells—generate a protein on their surface called CD4, which plays a critical role in immune system communication. This protein is commandeered by the HIV virus, allowing the virus to gain entry and manipulate the immune system during infection. As more and more CD4 covered cells become infected, they begin to die off. On top of this, HIV can even kill uninfected immune system cells. This is why HIV is named the “human immunodeficiency virus”. When the immune system is damaged, it is difficult for your body to fight against HIV or other opportunistic infections. One of the main obstacles to curing HIV infection is that the virus can remain hidden and inactive, or latent, inside certain cells of the immune system for many months or even years. While HIV is in this latent state, the immune system cannot recognize the virus, and antiretroviral therapy (ART) has no effect on it.
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Antiretroviral drugs have made HIV a
to cure HIV infection. Romidepsin belongs to
mild in severity and resolved within a few days.
manageable disease in the US and other de-
a general class of HIV drugs called latency-re-
The most common were abdominal symptoms,
veloped nations. Essentially, various agents are
versing agents, specifically a histone deacetylase
such as nausea, fatigue and some mild chang-
used to reactivate latent proviral DNA in rest-
(HDAC) inhibitor. HDACs are enzymes that
es in white blood cell counts and T cell counts
ing cells. Once the cells are activated, the hid-
keep DNA tightly coiled in a cell’s nucleus, so
were seen. Yet despite this evidence of increased
den viral DNA starts constructing more of the
it cannot be used to direct production of new
T-cell activation and renewed HIV replication,
virus. This makes the virus-producing cell visi-
proteins. HDAC inhibitors reverse this process,
the size of the viral reservoir, as indicated by to-
ble to the immune system and the escaping vi-
allowing proviral DNA gene expression and
tal HIV DNA in CD4 cells, did not change. This
rus is susceptible to ART. In the past few years,
production of new virus. Through this, laten-
means that while the virus was being taken out
physicians have started prescribing these drugs
cy-reversing agents can reactivate latent HIV
of the cells, it was not being killed.
to people who don’t have HIV, but who are at
within resting CD4 T cells. When latent HIV is
risk for contracting the virus in the future. This
reactivated, it is once again able to produce new
Most researchers think a combination
has proven to be a highly effective strategy called
virus and multiply. It is hoped that after latent
approach will be necessary to achieve a func-
PrEP, short for pre-exposure prophylaxis. Un-
HIV is reactivated, the CD4 T cells in which
tional cure that allows people living with HIV
fortunately, due to the high mutation rate of
the virus was hiding are more likely to die off
to remain off ART without disease progression.
HIV, PrEP is not a perfect prevention method.
on their own or be recognized and killed by the
As virus is released from resting cells, the im-
body’s immune system.
mune system will need to recognise and attack
In essence, a cure for HIV can be broken down into two parts. The first of which is draw-
it. Researchers have enrolled participants in a
ing the virus out of the cells, and the second is
Currently, clinical trials for Romidepsin
new study looking at romidepsin in combina-
boosting the immune system so that it is able to
are being conducted. These trials have phases,
tion with a therapeutic HIV vaccine (Vacc-4x),
fight the virus.
each with a different purpose and helps re-
which bolsters the efficiency of the immune sys-
searchers answer different questions. In phase I
tem.
Thus, after almost forty years after the dis-
trials, researchers test an investigational drug in
covery of HIV a truly preventive HIV vaccine is
a small group of healthy people, usually around
Within the next few years the results of
clearly still many years ahead. Nonetheless the
20-80, for the first time. The purpose is to eval-
these trials will either lead us to an eradication of
development of a vaccine for such a novel and
uate its safety and identify side effects. In phase
HIV, or with greater knowledge on how the virus
difficult pathogen, with only a quarter-century
II trials, the investigational drug is administered
functions, which is why it is imperative that the
of knowledge to work with, is not necessarily
to about 100-300 people to determine its ef-
research into Romidepsin is made known pub-
unimaginable. There is one drug in particular
fectiveness and to further evaluate its safety. In
licly. An amelioration of this sort would greatly
that has garnered more attention over the years
phase III trials, the investigational drug is ad-
increase the awareness of patients, and would
and has shown promise.
ministered to approximately 1,000-3,000 people
drastically dissolve the imminent danger of one
to confirm its effectiveness, monitor side effects,
of the world’s most lethal disease.
Romidepsin is a medication that has been
compare it with standard or equivalent treat-
approved by the FDA for the treatment of cer-
ments, and collect information that will allow
tain types of cancer. It is currently being studied
the investigational drug to be used safely. In its
to see if it could be effective as part of a strategy
trials, all romidepsin-related side effects were
Zahraa Abbasi, Grade 11
21
GENE Silencing: siRNA
22
Since Rosalind Franklin’s discovery of the double helix nature of DNA in 1952, the field of Molecular Biology was born. One key principle of this field is the central dogma, which states: DNA makes RNA which makes proteins. This simple statement has so many implications in the study and application of modern biology. When researching the field of molecular biology it is important to understand that genetics is just a flow of information that starts with DNA and ends with the formation of proteins. DNA is like a restricted library; it holds all of the information necessary to make proteins. However for the body to use the DNA library, it needs a system of copying the information in it. This first step is known as transcription, where the information held in the DNA is transcribed into a one stranded molecule known as messenger RNA. The information in the DNA is still in the library, but now the body has a new and usable form of it, known as mRNA. However, the body needs to overcome another barrier because the information that is transcribed is in a different “language”. In order for the body to use the mRNA to produce a protein, the information must be translated.. This process is known as translation, where the mRNA goes through a biological translator known as the ribosome, which translates the information in the mRNA to string together individual molecules to create a protein. While transcription and translation are necessary components of protein creation, a protein is ultimately a reflection of the information stored inside the DNA library. The protein is finally created; what exactly do the proteins do? Proteins are so important to any living organism because they are involved in virtually all bodily and cellular functions. Proteins can be antibodies to help defend against antigens (foreign invaders in the body), they can be contractile proteins which are responsible
for movement, they can be hormonal proteins which help coordinate some bodily functions, and much much more. As much good function proteins can provide the body, they can also be very detrimental to a living organism’s well being. So, is it possible stop the production of these unnecessary proteins? In 1998 Andrew Fire and Craig Mello, discovered the biological process in which double-stranded RNA is used to silence gene expression, known as RNA interference. One key component of this pathway Fire and Mello observed is siRNA. To understand the impact of siRNA on cellular functions, it is important, again, to view this pathway as a flow information. The relationship between DNA/mRNA and Proteins is analogous to a command and a action. The mRNA represents a command, while the protein represents the action and interpretation of that command. For example, view mRNA as the sentence “Your test is next class”. In an ordinary system, the regular output would be as studying for the test or in the case of the cell producing the desired protein. However the words if he words “next class” were removed the sentence would now read “Your test is”. This phrase would not provide any value to a student and then the student would not study. Similarly, in the cell, a broken up strand of mRNA could not be used by ribosomes to produce the desired product. This is a general idea of gene silencing. What is siRNA and how is it involved in gene silencing? SiRNA, or small interfering RNA, are short pieces of double stranded RNA any-
that specific protein. Going back to the sentence analogy, the siRNA/Enzyme is essentially the complex that takes t h e
where 16-23 nucleotides. A common misconception among many high school students is that RNA can only be single stranded; however, double stranded RNA, dsRNA, can be found in many viral genomes or can be synthetically created in laboratories Once this siRNA is present in the cell an enzyme splits the siRNA in half and binds to one of the strands known the guide strand. This strand has a certain nucleotide sequence that can be complementary to a certain mRNA sequence. If the siRNA connects to its complementary mRNA sequence it can break down that mRNA, preventing it from producing
As mentioned earlier, p r o teins can be very harmful. Many deadly viruses and diseases, proliferate because harmful proteins are being produced. Viruses work by injecting their DNA or RNA into cells and use the cell’s machinery to produce proteins, which are essential to constructing new lethal viruses. Cancer is essentially the uncontrolled and rapid replication of cell. SiRNA has the capabilities to suppress certain oncogenes. An oncogene is a gene that has the potential to cause cancer by being expressed at dangerously
words “next class” out of the original sentence. Why is this important?
high levels, creating tumors. These genes transcribe and translate certain proteins that promote cellular growth. Through mutation, these genes can be amplified and overexpressed, leading to cancer. However, by synthetically creating siRNA sequences that are complements to these oncogenes, our cells can effectively silence these genes. Not only can this help cure cancer, but many other harmful protein related diseases. Ideally, siRNA is a very useful in medical applications, however, extensive research must be conducted in this field because successfully delivering siRNA to cells requires a complementary set of technology. In order for siRNA delivery to be successful, it must be injected i nt r av e n o u s ly and travel through the bloodstream to reach the intended target cells. In addition, in order for siRNA to target genes, it must be infused into the cell without being digested by organelles. However, the negative charge of siRNA prevents the successful uptake by the similarly charged membrane and also makes it susceptible to degradation by cellular enzymes. Although siRNA is very difficult to deliver to cells, its applications in gene silencing has the potential to significantly impact the field of molecular biology. Krishna Boppana and Ram Venkadesan, Grade 11
23
Together Ensnared in the World of TRAPPIST-1
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TRAPPIST-1: “Presenting humanity with many opportunities to study terrestrial worlds beyond our Solar System” What STEM-lover wouldn’t sign up for a planetary system with a résumé like that? Ever since the February 22nd NASA press release, the TRAPPIST-1 system has captured the world’s imagination for possibilities of life beyond our own dear, yet frankly boringly familiar, Solar System. The challenge laid out for our age is thus: Seven rocky planets. All possibly containing water. All with sizes and masses comparable to that of the Earth. Located just 12 parsecs away from us, just a little over the distance at which the absolute and apparent magnitudes become equal. Our solution: bring on the multitudes of physicists, astronomers, engineers, chemists, biologists, and even artists to unearth the vast potential this system holds! My earliest passion since I was 3 has been Astronomy. With beacons like Kalpana Chawla and Sunita Williams, I couldn’t wait to don my MMU propulsion unit and jettison off to worlds unknown. As I grew older, my eyes began to open to the myriad other fields that “STEM” encompasses and interacts with - from my mother’s Cryptography graduate lectures that I would sneak into, to Photography elective projects in school, and all the way upto my Partners in Science research last summer on increasing organic transistor efficiency by incorporating Nanotechnology, Materials Science, and Electronics. Learning Astronomy seriously for Science Olympiad showed me how, amazingly, every one of these fields could be used to glean information about various celestial objects. In fact, when asked during my PIS application interview about the interconnectedness of
STEM, I gave the example of how astronomers employed every tool in science (and beyond) to uncover the identity of a celestial object. Spectroscopy from chemistry, orbital motions from physics and mathematics, topology from geology, economics from metallurgy, and even spaceship structure from origami are just a few of these techniques. In fact, Astrobiology is one of the hottest topics in the spotlight today, because it gives a sense of what conditions life can exist in, and whether that life is anything like what we imagine it to be. So one can imagine the delight that practically every member in any field may have experienced when TRAPPIST-1 was announced. Here was finally the pilot case, the uncharted territory that people like me and you (by the fact that you are reading this magazine!) have only dreamt of in our midnight fantasies. From announcements of cloud-free water-vapor filled atmospheres by meteorological spectroscopists Julien DeWitt et al. to the near-perfect resonant chain of small integer-ratio orbital periods by astrophysicists Michael Gillon et al., professionals in every field, some awaiting results from others, cannot wait to get started with the possibilities this spectacular case study presents to us. Look at the image with this article. Featured on the 23rd February 2017 issue of Nature, it beautifully conveys the planets that potentially hold splashes of liquid water to the ones that may hold reservoirs of frosty ice (like Jupiter’s moon Europa). The steam is, of course, from planets a bit too close to their star but still within the habitable zone. Imagine how much closer humans have come to understanding their own origins if we can discover and study systems so similar to ours! None of this would have been possible without the efforts of interconnected STEM, Arts, Economics, Religion, and myriad other fields working in conjunction. Thus, the next time you see different fields disagreeing on a topic or not communicating their latest finds in a constructive manner, be the voice that builds something beautiful and utilitarian from this juxtaposition because chances are, you may discover a system more wonderful, more awe-inspiring, than even TRAPPIST-1 here... Priyanka Dilip, Grade 11
The Ocean Above Us Growing up, I’m sure many of you have heard some sort of explanation of why the sky appears blue. Self-proclaimed scientists declared that the sky is simply a reflection of the ocean, proudly citing the “expertise” of their parents; others stringed together buzzwords such as “light”, and “reflection”, trying to sound as scientific as possible despite having absolutely no clue of what they were talking about. Who knows, maybe even some of you still use these explanations to this day to answer a seemingly simple question - no worries though, you’re kinda right. In order to understand the science behind a blue sky, we need to first understand the interactions between the radiation from the sun and the earth’s atmosphere. The sun emits radiation in the form electromagnetic radiation, which can be classified as both a wave and particle (packets of energy known as photons), called wave-particle duality. Electromagnetic radiation can be classified according to their wavelength, or the distance between two “bumps” of a wave. Most of the radiation coming from the sun is in the form of visible light, ultraviolet rays, and infrared rays. Earth’s upper atmosphere reflects most of the long wavelength, high energy radiation, such as gamma rays and x-rays, and allows radiation with shorter wavelengths, such as visible light and infrared rays, to penetrate the atmosphere. While traveling through the atmosphere, radiation interacts with the different components of the atmosphere, which include nitrogen, oxygen, carbon dioxide, and argon gas, as well as small amounts of water vapor and dust, which prohibit electromagnetic radiation from traveling in a direct, straight path to earth. Radiation is reflected and scattered by matter in the atmosphere, which plays a key role in creating the blue sky we are so accustomed to. Interestingly, radiation emitted by the sun is scattered to different extents by the atmosphere depending on the wavelength of the radiation. For example, in one form of scattering, called Rayleigh scattering, where the scattering particles are much smaller than the wavelength of light, the smaller the wavelength of light, the more strongly scattered that particular wavelength of light is. Other forms of scattering exist, such as Mie scattering, where the scattering particles are approximately the same magnitude of the wavelength of light,
and non-selective scattering, where the scattering particles are much greater than the wavelength of light; however, Rayleigh scattering accounts for a majority of the scattering of blue light, which ultimately gives the sky its characteristic baby blue color. To give some context: the visible portion of the electromagnetic spectrum is split into the colors of the rainbow, with red light having the longest wavelength, and violet light having the shortest wavelength. And following the progression of colors in the rainbow, you can determine that blue light has one of the shortest wavelengths out of all the colors in the visible spectrum, and thus experiences intense scattering by the atmosphere. As a result of this intense scattering of blue light by the atmosphere, the sky appears blue, yet not completely blue - it is important to note that other colors of light are scattered as well, but to a much less extent than blue light, which gives the sky a slightly white tint. Some of you scientific sleuths may be wondering, “Hey! If violet light has the shortest wavelength out of the visible spectrum, and you said that shorter wavelengths are scattered more intensely, how come the sky isn’t violet?” Well, this phenomenon stems mainly from two sources: one, the sun, and two, us human beings. There is a famous law called Wien’s displacement law, which essentially states that the wavelength of the most intense radiation from an object will depend on its temperature; using this law with the average temperature of the sun, it can be determined that the sun actually emits the most intense radiation at a wavelength of about 502 nanometers, which is located in the blue light portion of the visible spectrum. Naturally, the blue appearance of the sky can be partly attributed to the fact that the sun emits the greatest magnitude of radiation in the blue light portion of the spectrum. In regards to us human beings, our eyes are actually less sensitive to violet light in comparison to blue light; we have three color receptors in our retina, programmed to respond most strongly to light in the red, blue, and green portions of the visible spectrum. The properties of our eyes coupled with the fact that blue light is the predominant form of radiation thankfully makes our sky appear blue. Imagine if our sky was purple; how would parents explain that to their kids??
Matthew Kim, Grade 11
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Understanding LEDs, and then Using LEDs to Approximate Planck’s Constant in a DIY Experiment Those in the group of students who have made it through AP chemistry (or the first few months) had a chapter covering quantum mechanics and in that chapter some focus was given to the energies of photons as a result of moving valence electrons away from the atomic nucleus a certain distance. It is likely in that time that you may have run across the equation:
For those who have not yet taken AP chemistry (or do not want to (you really should take it)) what is occurring is similar to spinning an object on a stretchy cord and watching that as it spins faster (and thus has a higher kinetic energy) it travels in a larger radius. The same idea is occurring around the nucleus of an atom. As the electrons that move around the nucleus get excited due to energy being dumped into them, they move faster, and jump out to a larger radius.
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What you see here is the bohr model of an atom. While it is technically not the cutting edge, it arguably does a better job at explaining this equation. The circles labeled N=1/2/3 can be viewed as possible paths for the electron to
move about. If we look at the space between these lines as bowed inwards then we can get the general idea of orbitals and shells. Using the power of Google Docs drawing here is the best I could do:
men, who take physics first and thus are well prepared or future science, can follow along. So,
means that the wavelength of a photon that is released following an inwards orbital change is equal to
What is occurring is that; due to the attraction between the electron (which would be rolling around the nucleus in the channels (specifically in the zone marked favorable (these are known as shells))) and the proton(s) in the nucleus the electron has a natural tendency to reside in N=1 however as it gains energy, it will have to seek a larger radius orbit (F=MA let’s say F is constant as is the mass of the electron so therefor A is constant as well (if (A=V2/R)Then as the KE of the electron increases R must increase as well)) . Due to the curved wall that contains its path, it will eventually gain enough energy to rise up the wall (while fighting a fictitious force that helps the need to energy increases to jump out be explained) and then fall into the area of N=2. As the wall holding the electron in the N=2 path will now provide a force counter to that of the attraction of the nucleus should the electron try to move in, the electron must dump the same amount of energy it took to climb out of N=1 into N=2 in order to jump back into N=1. What we just saw here then was an energy transfer problem. A specific amount of work was done on the electron to make it move out, and then the electron released that same energy in order to fall back into the center. And this energy that the electron drops all at once is emitted as a photon which has a specific wavelength (λ) due to the equation which I dropped above! So, with this fairly tame physics we can at least approach this problem with some understanding, meaning that even our lucky fresh-
What are E, h and C? E is the energy or work done to move the electron, h is Planck’s constant and C is the speed of light. Planck’s constant is defined as 6.62607004*10-34Js. A Joule Second is a measure of work (F * D) times time (S) results in a unit of power. Thus, if we do our factor labeling correctly, we should find that the two work units (the J in h and the E which it is divided by) cancel as does the seconds in h with the m/s in C. Thus this leaves us with a stray meter which is indeed a correct unit of measurement for wavelength. But let’s say that this is too easy, and try to find this value instead. The Experiment: The whole idea behind this came from playing around with some high power 10-100W LEDs. I noticed that the infrared 940nm LED was at its peak power rating at only 12V whereas the blue 450nm LED required nearly 35V to reach full power. I had recently done some reading in an attempt to build my own LEDs and thus was exposed to a phrase/term known as band gap. A band gap in an LED is best viewed as an area where two different types of material used in the diode meet and in this area an interesting event occurs. As their name implies, semiconductors are not great conductors, so in order to allow electrons to flow through the material a certain amount of work must be done to “push” electrons into higher energy states where electrons can be transferred. However once these electrons are “pushed out” they then will migrate to the second material of the LED, where electrons are readily accepted. Thus the accepted electrons now have excess energy, which
is dropped as a photon of a wavelength corresponding to the amount of work done in the first place to get that electron into a state of being conducted. Depending on the materials used in the diode, the energies of this band gap change resulting in different wavelengths of light being emitted from the diode. Now that a very basic idea of how LEDs function has been presented, let’s get back to the experiment.
Having free time I decided to record the voltages that the LEDs required to run and compare that with the wavelengths they claimed to produce. (the eBay seller gave a +/- 5nm range) in an effort to keep as many things constant as possible, I used the current limiting feature on my power supply to provide as close to .1A per LED. I then would turn up the voltage until I reached this current limit and record the voltage. I used all of the LEDs of this variety I had in order to get a range that somewhat covers the near UV all the way to near IR, The numbers were then divided by the amount of LEDs in series (these 100W LEDs use rows of 10 LEDs in series meaning 10 times the voltage) averaged over three trials The numbers went as follows: 940nm IR
750nm R
590nm Y
532nm G
480nm B
450nm B
365nm UV
1.16 V
1.64 V
1.96 V
2.18 V
2.59 V
2.76 V
3.12 V
Why does the voltage matter? As mentioned above, a certain amount of work is required to allow the electrons to transfer through the LED junction. Those in AP Physics C will be familiar with the electron Volt or eV which represents the amount of work done by a 1V potential difference. So, if we are applying X many volts to get the LED to run, then we are really
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doing X many eV of work to get the LED to run! A single electron volt is a minute 1.6021*10-19J but that is okay, as a single photon is also very low energy, so low in fact, that the human eye cannot see a single photon of any wavelength. Using the equation to relate wavelength and frequency, we find that
This means that we can rewrite the original equation of
as E=hF which is useful as it removes C from this final state. As one can see using the equation, the frequencies of visible light are very high, thus meaning that h must be very small if the end energy of the photon is to be very low as well. Graphing the work done in electron volts and the color of the light in frequency should yield us a slope of h. Here is what I got: (I set the origin as a point, as plugging a 0 in the equation will give us 0 energy.)
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Because of a (0,0) intercept, this line works out quite well into a perfect linear equation with a slope which is not a perfect, but still a fairly impressive value, of 6*10-34 (tragically excel dropped the sig figs so we will never know if it could be better…). Comparing that to what we know to be
Planck’s Constant of 6.62607004*10-34Js we need only now check the units. The frequency is is Hz, and the resulting energy is is J So, the Js unit in Planck’s constant must cancel with the unit of measurement on the frequency in order to yield J. Affirming the math, frequency is measured in the in Hertz Hertz which is s-1so the s in Js and the cancel leaving us the J we were looking for. Considering this was done in a few hours the hardest part of such an experiment is understanding the LEDs (you can do this without understanding them, but that sort of diminishes the magic (please read more on LEDs if you want deeper answers, I am certainly not the best person to describe them)) and getting them. (look up the wavelength you want as “X”nm LED chip on eBay, and buy the cheap 1W, 3W or 5W versions as they are many times less expensive, and will likely yield better results as there can be no question as to how uniform the LEDs are performing due to there being only one LED on the chip. Then wait two to three weeks for shipping from China and enjoy.) To those who read this and then perform this experiment let me know how the results come out. You can reach me at joseph.florentine@mtsdstudent.us.
Joeseph Florentine, Grade 12