A Guided Tour of the World of Experiments

Time has gone by so quickly! I am still in shock that tomorrow is my last day of class. Even thought we are so close to the end, we continue to learn more about the way experimental physics works in the real world. One thing that has changed in the final couple days is that we are beginning to learn about it from many different sources. In addition to the guest lecture today I heard from my fellow classmates (and got to teach them a thing or two myself) as well as some of the grad students that populate the basement of our building, working on some groundbreaking studies with radio telescopes, carbon nano-tubes, and soft matter.

The day started off with a very interesting guest lecture about the construction of SNO (Subdury Neutrino Observatory), a huge neutrino detector placed at the bottom of a nickel mine to shield it from unwanted background information. By studying these subatomic particles that can travel the distance between us and the sun in just over eight minutes, we can learn a lot about the nuclear reactions occurring at the suns core currently. It turns out the data also proves the Standard Sun Model, which had previously been questioned because previous experiments did not account for oscillations that can change the "flavor" of neutrinos. The most interesting part of the lecture for me was seeing the journey from the first detector that failed to collect conformational data and the confusion that insued, to the construction of SNO and the steps that led scientists there. That is truly what experiments are all about: dealing with confusion.

Another great part of the day was listening to the experiences and findings of the classmates who worked on different interest groups than me. Groups gave presentations on cloud chambers, measuring cosmic rays, using radio telescopes, and a number of other really fascinating things. Something really exceptional about the presentations was not the data they got (although sometimes, when they came really close to the accepted value that was also neat) but the experimental process that each group preformed, and in some cases designed.

To be completely honest, my favorite part of the presentations was the part where my group got to share our experience with quantum mechanics and electron/photon diffraction. It was a really cool feeling being able to tell a group of people about the data that we collected ourselves and the significance of it, especially because particle/wave duality is such a mind-bending phenomenon that is crazy just to think about, let alone explain. My group faced the challenge quite elegantly and we sat down knowing that each of our peers knew a little bit more about the amazing concept that we could prove with our own data.

After lunch, we went on a tour of the grad labs, which gave me more of an idea of what the field of physics actually looks like than anything we've done in class before. Young students with excited smiles and scraggly beards showed us the equipment they worked with and explained to us why they were interested in the field they were currently researching. It was clear it was a lot of hard, and possibly tedious work, but it was also clear that each of them was genuinely excited about what they were doing and confident that the work they were doing was both significant and completely awesome. It was an environment I can see myself fitting right into.

Our PENNultimate Day

Today was exciting from the start because we began our class with a talk with Rick Vanberg. For the first few minutes I munched on my bagel and listened, but soon his talk became quite captivating. The first thing that Rick talked about was the standard nuclear model for the sun. Based on the observations of nuclear activity on small scales, scientists came up with a model that accounted for the gravity, high pressure, and high nuclear activity in the center of the sun. One problem was that the accepted model at the time predicted a large number of neutrinos would be released for every fusion reaction in the sun.

Because there are so many reactions every second, scientists predicted a certain number of neutrinos per second would hit each meter of the Earth’s surface. To test this model, a scientist filled a large vat full of liquid and then waited for a while. Although the experiment was underground, neutrinos are tiny and have no charge so they very rarely interact with the matter in the way. When the neutrinos strike the liquid, they are absorbed and they change the atom that they strike into a different element. When he took the measurements of the number of neutrinos that he detected, he found that there were only about 28% of the neutrinos that there should be.

To solve this conundrum which either implied that our model of the sun was totally wrong or that we didn’t understand neutrinos, a Russian scientist stepped up to the plate. Communicating through the veil of the Iron Curtain, this scientist published several papers where he claimed that we misunderstood the neutrino. To test this claim, a project called SNOW was developed. Snow basically consisted of a huge neutrino detector built to detect all kinds of neutrinos unlike the past models. To filter out background radiation, SNOW was built 2 kilometers beneath the surface of the Earth in a nickel mine in Ontario. SNOW ended up successfully measuring all of the neutrinos that came from the sun and we learned that the neutrinos were being morphed into other flavors and that the nuclear model of the Sun is actually correct.

Next on our schedule were the student focus group presentations. Each of us spent 4 days last week with our groups researching a subject that we picked. My group studied a non-Newtonian fluid called oobleck which basically means that it is a material that behaves both as a solid and a liquid. The peak of our presentation was on Monday when we used the oobleck in a demonstration. Because oobleck acts a solid when it’s under pressure, each of us could run over it. Today, we showed some graphs of how objects decelerate when they hit oobleck compared to when they hit water. The graphs were neat because you could really see how the oobleck gave away for a moment and then hardened and stopped the incoming solid whereas the water allowed the object to easily pass through. It would be way too much to talk about every other group’s presentation, but they covered many amazing topics such as quantum mechanics and radio astronomy. Each group had a unique perspective to offer and we all learned a lot from each other.

When we returned for lunch, we got to do something pretty interesting. We split into groups and then visited different parts of our building and the one across the street. We got to go into research labs and listen to brief talks by the researchers themselves about what they were working on. The first lab we stepped into was a lab where a grad student and a professor from UC Santa Barbara (WHOO California) were developing technology for better mammograms. Because current mammography methods require the breast to be squished tightly between pressure plates so that the waves could get better images, these researchers were searching for a way to do mammograms with near infrared light. The advantage of this is that the discomfort of the plates could be avoided and therefore more women might show up for their mammograms. I was impressed by how applicable this research seemed and that it truly was for a good cause. We heard many other talks about great stuff like carbon nano tubes and grapheme. These researchers were researching grapheme so that they could manufacture tiny detectors for things such as bomb detection. Overall, I was very impressed by how passionate these researchers were about their areas of study.

I am in shock that tomorrow will be my last day here at UPenn, but who knows; maybe I’ll be able to spend another 4 years here.

Thanks to Alex for capturing Julia's momentary lack of enthusiasm.

The Day is Almost Here...

Today was much less intense than the past couple of days. We began with a lecture from a well known particle physicist, Rick Van Berg. Rick primarily designs detectors for particle physics experiments. He has done a lot of work in the Cern Laboratories in Switzerland, home to the smartest scientists of this age and the best particle accelerator in the world. Lately, he has been working in the SNO facilities in Ontario, Canada. SNO stands for Sudbury Neutrino Observatory and it too is one of the best research facilities in the world. His lecture was actually all about Neutrinos, which is a basic particle that usually travels close to the speed of light, can pass through most matter unaffected, and is electrically neutral. He discussed the origins, discovery, and research of neutrinos and it was all fascinating. For instance, the SNO facilities are basically giant clean rooms, much like facilities in which they produce computer chips in. Professor Van Berg told us that if even a teaspoon of dust were to be introduced to the facility, every project would be ruined. I always find the stipulations that are put on certain research environments interesting. I like seeing all the effort that scientists and researchers are putting in to reduce their possibility for error as much as possible. Professor Van Berg covered one of the more difficult and complex lectures, but his was much more understandable than some of our other lectures.

After lecture, we continued with our presentations. I was very excited to watch these demonstrations because I wanted to see what kind of work my friends and peers had been doing for a week. I was also anxious to see how our data and experiments would stack up against theirs. When it came down to it though, our topic was quite different than most of the other groups’. While most of the other groups were doing experimentation for the majority of the week, we were being given lectures about radio astronomy and the tools used to study it. This was completely understandable though. Although we did not do many experiments, we needed to know how everything worked before we could understand what exactly we were doing before we could actually do it. This really made our presentation stand out because our data section was short, but our general and background information was much more extensive than the other groups’. Mary told us at the beginning of lunch that she though our presentation was a nice change from the rest and that our information was plentiful and well-organized.

Following lunch, we split into four groups to tour different labs around DRL. I didn’t realize that there were so many different kinds of research going on in the DRL. We visited medical labs, cosmology labs, and even soft-condensed matter labs, which deal with matter that has both the properties of liquids and solids. Mostly, we spoke to grad students that were doing research in the lab. They were able to tell us all about the projects they were working on. One of the most interesting projects we saw (in my opinion anyway) was a machine that was being developed that would use near-infrared waves to sense tumors. The research was mostly focused on improving scans for breast cancer, but it was also applicable to scanning other tumors and also brain activity. It was truly amazing work. Of course each of the labs was showcasing the best of what they were working on and each of them told us why their specific field of research was one of the best. It was interesting to hear about the different research styles and opportunities that all of these grad students have. It was even better to hear that undergrads are also allowed to study in these labs and perform research. Our visits to these labs were truly enlightening because it gave me an even better glimpse of what kind of research opportunities I could potentially have in college.

Sample data collected by grads and undergrads

Professor Van Bern discussing ATLAS, another project he worked on

After class, I continued packing a little bit. I’ll finish tomorrow before the room check, but it’s definitely not something that I am looking forward to. Once 6:00 came around, my floor and our RC, Carlos, went out to Bobby’s Burger Palace for a group dinner. Apparently the Bobby, after which this restaurant is named, is THE Bobby Flay. I didn’t realize this until we walked inside and there was a whole section of the counter dedicated to Bobby Flay marinades, spices, and cookbooks. The food was amazing as well. It was just a burger and fries, nothing too extravagant, but it was just so delicious. The burger was cooked to perfection and the fries were perfect. I couldn’t imagine a better way to come together as a floor. We all took a group picture out front, but we only had time for one shot because we had to be back at the quad as a group before a certain time. Unfortunately my camera was not the one used, but my friend and floormate Sachit’s. He will be uploading the picture to Facebook soon and I will be sure to use the shot in my reflection blog.

Everyone approves of Bobby's

We returned to the quad and got as much of the group together as we could. Since this is our last full night here at Penn, we wanted to enjoy our final moments hanging out in our lounge-like dorm. Although Fred, Abheek, and Julia were busy, Alison, Brian, Onur, and I still had a great time. We talked, we laughed, but most importantly we just enjoyed each other’s company. Being together in the dorms and lounges is what I’m going to miss the most about being at Penn. These nights were often the highlights of my days and I will always treasure the moments I’ve had in our little family of seven. The end is near.

One day remains.

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