Wednesday, July 27, 2011

A Unifying Theory

We got right to work today with a morning lecture about nuclear physics from Ryan, one of the very helpful and knowledgeable assistant teachers. The first couple slides were about the history of nuclear energy and the discovery of x-rays. Ryan went on to explain the physics behind alpha decay, beta decay, and gamma radiation (during this part of the presentation, our previous lecture about the standard model came up again and it was necessary to recall the concept of leptons and quarks). The remainder of the lecture was devoted to explanation of applications of radiation that are highly important both within and independent of the realm of physics. We discussed the benefits and waste products of uranium mining, the breakthroughs and limitations of radiation as a cancer treatment, briefly touched on the subject of mass spectrometry and how radiation can be a helpful tool in studying the origins of the universe. Towards the end, the lecture transformed into more of a discussion that was so lively and obviously relevant, that I found myself more engaged than I had been during any previous first-thing0in-the-morning lectures.

After Ryan's talk, we were given a short break to let the information soak in a little and to give us time to prepare for our presentations of the Hershey Park Rides. It was a very different experience hearing from groups of fellow classmates as opposed to professors and teachers. Each group went on a different ride, so the data was unique in that regard, but each team's presentation and analysis of data varied greatly as well. Some groups were able to record videos and sync them to their data, others calculated the resultant total acceleration based on the x, y, and z values they collected. One group even had a three dimensional animation of altitude v. y acceleration v. time. By the end of the day, I had learned a lot from my fellow class mates about creative ways to handle data in a way that makes sense to your particular experiment and goals.

When all the presentations were over and we returned from our lunch break, we prepared for our guest lecture by watching "Elegant Universe", the PBS show on string theory. As I was watching, I realized that I had seen parts of the show before; my fifth grade teacher played if for our class. At that time it had come out only a few months ago. I remembered the movie distinctly because it was a moment in my life when I realized both how incredibly cool science could be, and at the same time, how very little I understood about the complexities of it. Watching the film this time around, I understood many more of the concepts, but the sense of wonder was not lost.

Only moments after watching the program he was quoted in, we got to hear from string theorist Burt Overt himself. He described to us, in much greater detail than the movie, the basic concepts of string theory, the implications that the theory has, why it makes sense in the real world, and the ways in which it can be tested.

The basic definition of string theory is the hypothesis that the smallest components that make up the universe are not particles but tiny strings that vibrate at different frequencies to create different kinds of matter. The mathematical calculations that have been done suggest that such a theory means that there must be 6 other dimensions besides the three spacial dimensions and time. The concept of extra dimensions is a hard one to grasp, but it made more sense to me today than it ever has before when Dr. Ovurt did a demonstration with a rolled up piece of paper. Another implication of string theory he discussed was the concept of supersymmetry, meaning that for every particle, there is a so-called "sparticle" that also exist. These particles have yet to be found because they do not appear in low-energy circumstances, but Ovurt has high hopes that CERN will provide the environment necessary to make significant breakthroughs in the subject.

It was fascinating listening to an expert talk about a field that is at the very outer edges of the scientific frontier. The fact that people in the class asked questions that no one in the world has answers to, but that Ovurt is actively working on discovering was almost too much to comprehend.

After class, we had a few hours to wander campus before we went out to dinner with Mr. Miranda and the Yale chaperone. We ate at City Tavern, a place I had been interested in visiting since our initial tour of the city. The food they serve is all based on the typical cuisine of the taverns of the 18th century that our country's founders used to eat. While we munched on some sweet potato pecan rolls (apparently one of Thomas Jefferson's favorites) we discussed not the past, but the future: our plans for senior year, applying to colleges etc. When dinner was over, we visited an ice cream parlor, a great end to one of my last days here at Penn.

Today Was Truly a Rollercoaster...

Our final days in class seem to be getting more and more complicated. Today we began class with a lecture from Ryan on nuclear physics. The subject material was confusing at first, but he was able to make it accessible. He told us that this was one of the most important topics that is almost never covered in high school physics classes. Since this is an issue that will invariably affect all of our lives. Nuclear reactors and energy has been an issue for several decades and, with the approach of peak oil and the need for alternative energies, will continue to be an issue in the coming years. Since this is a prominent issue, people my age need to be informed of just how nuclear physics works so they can make informed decisions. With that said, I found his lecture to be quite informative. One of the points that Ryan made that I found quite funny was that a plate that one microwaves several times over a long period of time will be more radioactive than a cell phone. Since there is a lot of worry over the radiation given off by cell phones, I found it ironic that people don’t even realize that there is a bigger danger right in front of their noses. This just demonstrates why people need to be informed about nuclear physics. I found that it fit the situation perfectly.

After Ryan’s lecture, we did our presentations on our Hershey Park rides. Our group was the fifth to present (out of eight) and I would say that ours was one of the better presentations. Each of our PowerPoint presentations had their strong suits, whether it was creativity, enthusiasm in the presentation, or being strong in data analysis. One group even produced a 3-D model of their coaster in a graphing application on one of their member’s Mac. All of the groups kept their presentations entertaining as well. The group that was assigned the Great Bear filled their presentation with bear puns (it was almost un-bear-able). I had a great time watching all of the presentations and it made me look forward to the presentations that we will be giving tomorrow.

Our guest lecture followed lunch. Today we were visited by Dr. Burt Ovrut, a string theorist who teaches Theoretical High Energy Physics. String theory is an active research framework in particle physics that attempts to reconcile quantum mechanics and general relativity and is a contender for the theory of everything, a manner of describing the known fundamental forces and matter in a mathematically complete system. That was the definition that Dr. Ovrut gave. In layman’s terms, string theory is the theory of how everything in the universe is tied together by basic elements called strings. In his lecture, Dr. Ovrut discussed the possibility of other dimensions that are parallel to ours and are unreachable, different particles that may exist, such as gravitons and sparticles, and even membranes, which separate the dimensions. The lecture was extremely difficult to follow. The pace of the discussion was non-stop and you either had to keep up or get left behind. I would like to understand string theory better someday, but before then I will definitely need to work a lot harder, and I am prepared to take on that task.

After lecture, Brian and I headed back to the dorm. He began his summer assignment for AP Lang and I decided to begin packing so I don’t have to do all of it on Friday afternoon. It was actually kind of sad because I felt like I was taking apart different pieces of the home that I have built over these three weeks. My desk is much cleaner, my closet and drawers are nearly empty, and my suitcase is about half full. I know I will be glad that I started packing today, but when I was taking down the wall mount I had made for my lightsaber, it was quite saddening. It is still hard to believe that I will be returning to California soon.

Around 6:20, we met Mr. Miranda in the office so he could sign us out for dinner. Much to my surprise, we dined with Ms. Nardone again, the Yale chaperone. We ate dinner at an old fashioned restaurant at Penn’s Landing that was set to the theme of an older Philadelphia, around the time of the Founding Fathers. The attire for employees, decorations in the restaurant, and even the meals felt like they were ripped straight out of a history book. I enjoyed the venison medallions with a starter called mushroom toast. The toast was basically just marinated and grilled mushrooms over a piece of bread that was toasted to the consistency of a crouton. It was delicious and almost as good as my entrĂ©e. I had never had venison before this meal, and it is one of the best kinds of meat I’ve ever had. We also got the chance to get to know Ms. Nardone a little bit better thanks to this dinner. She’s a very interesting and knowledgeable person and I think the Yale group is very lucky to have her as a chaperone. After dinner we stopped by an ice cream parlor called the Franklin Fountain. It is the Philadelphia equivalent of Fenton’s in California. The ice cream was truly amazing and I wish we could have gone sooner. The parlor even had a section in the back with shelves full of vintage soft drinks, including bottles of RC Cola, Dr. Pepper, and several brands I had never heard of before. At first I was sad that I would miss the talent show to go have dinner, but I had a great time and I wouldn’t trade it at all.

A true colonial...kind of...

Ice cream in a Chinese take-out box...I approve

When we returned to campus, we had a meeting in the lower quad to discuss our last few days in Summer Discovery. Ed told us that normal rules would still be enforced, even though some people may think that everything is basically over, and that he didn’t want us to be sent home prematurely just because of something stupid that might be done on the last day or penultimate day. He also told us about our check-out procedure and that our rooms need to be clean by 5:00 on Friday afternoon. We were also given an evaluation form to evaluate the program as a whole and even the Summer Discovery staff that we interacted with the most. After that, the night was pretty laid back, which was more than welcome after the mind-boggling guest lecture and traumatizing experience of packing from earlier today.

Two days remain.

Time's Flying

I stepped into class today with a couple of bagels from the campus bakery and took my seat. I’d have to say that today is the first day where it’s really hit me that I have to go home in only a few days. It’s hard to walk anywhere on campus without seeing a few Ben Franklin quotes, and I think one of the ones that has stuck most is, “When the well is dry we know the worth of water.” I’m realizing now that I only have a few days left here so of anything I’ll try to appreciate them more than any of the others instead of whining about it. Anyways, I was in a very receptive mood for Ryan’s lecture on radioactivity and I think I learned a lot from it.

Ryan first discussed the development of what we know about the atom and how we learned it. This stuff was mostly review for me because of my chemistry classes, but it honestly amazes me every time how scientists such as Thomson and Rutherford pieced together an accurate model of the atom while everyone else thought they were crazy at the time. It also impresses me how each of these atomic models built on the last but did not totally discard. Thomson proposed that there were positive and negative charges in the nucleus and Rutherford discovered that the nucleus is actually a dense positive center. This model was improved on by Niels Bohr where he theorized that electrons orbit the nucleus much like planets do the sun. This was later revised, but the ideas of each of these scientists were still kept in some form.

The next part of Ryan’s lecture was talking about the uses of nuclear energy and a few common misconceptions about it. One of the first things he summarized is how a nuclear reactor works. By packing together fuel rods near each other, the excess neutrons from an atom fly out and then hot another atom which produces a couple more neutrons for each one that hit it causing a chain reaction. Then, what surprises a lot of people is that this energy is simply absorbed and used to boil water. From this point on, the power is generated just as it is in any other power plant; the steam is used to drive a turbine which turns a magnet which creates a current.

One of the first misconceptions that Ryan sought to debunk is that many people think of radiation as dangerous and very negative. What many people don’t realize is that radiation also has many applications that are very beneficial to humans when controlled properly. One of the biggest areas radiation is used to benefit humans is in the medical industry. As I believe Ryan pointed out, the acronym MRI is really missing a letter; it should really be NMRI which stands for Nuclear Magnetic Resonance Imaging. MRI machines use carefully aimed radiation to get something like an X-ray of your body, but 3 dimensional and with a low dose of radiation. Furthermore, radiation can be very carefully aimed at malignant tumors in the body to kill them before they mestastethize. Although this treatment is not always successful, it can help in some cases and is certainly a good application of radiation.

The day only got better as we got further in, because the next part of our day was about string theory. We watched a brief movie on the fundamentals of string theory, and then talk to one of the leading experts in the field, Burt Ovrut. The fact that Burt truly talked to us and didn’t have a lecture prepared made his talk extremely valuable because we could easily tap his brain about any part of the subject we were interested in. The basic premise of the talk was that string theory proposes that the universe is full of tiny vibrating strings that when struck at different frequencies act as the ‘particles’ we commonly observe. I will avoid trying to dump a huge amount of information here, but the reason that string theory is so important is because it could unify all of physics as we know it. Today, physics is a shattered mess of quantum mechanics, general relativity, and a bundle of different forces. String theory is intriguing because when you work out the complex equations, there are simple solutions to these complicated problems. For example, string theory predicts only one force instead of the gravitational, electric, magnetic, strong, and weak forces as we know them today. As Bill always says, it’s only philosophy until there’s solid evidence, there is little evidence to support string theory today. However, the Large Hadron Collider in Switzerland may well find evidence for or against sting theory, and guess what college physics program helped develop some of the detectors for the LHC. That’s right, scientists at UPenn helped. It’s very exciting to be around a place where there is so much progress going on.