Today was certainly out of the ordinary. Class had a different feel to it today and my time after class turned out better than I expected it to be. We started the day with a lab, which is very different from our usual schedule. We got together in our groups from the trip to Hershey to experiment. Our task was relatively simple. We had to balance a scale. However, this was no ordinary scale. This did not have a platform for weighing objects. Instead, it used metal rails for positioning very light objects (we used one-hundred milligram wires) and the scale was not used for weighing the objects we placed on it. Once the scale was balanced and hovering about a millimeter above the main body of the scale, we applied a current to the rails, which caused it to rise because there were two rails with opposing currents. Because the currents opposed each other, they were repelled. This would only happen if we applied a minimum amount of voltage so that the rails would repel so much that the top rail would overcome the forces that the wires pressed upon it. We found that the results supported our hypotheses. We observed that the amount of voltage needed would need to increase as the amount of weight on the rails increased.
Craig lectured us today and it was quite different from the lectures we have had before. Today’s topic was about General relativity. I was unaware that there were actually distinct categories of relativity, but it is actually divided into special relativity (which is what we covered previously) and general relativity. I was lost at the beginning of the lecture because the whole concept of the lecture revolved around idea that defied the theories and laws that we had learned before. Craig began by saying that general relativity was just geometry, but was a bit of a stretch. Although the ideas involved in general relativity are grounded in geometry, they quickly go against many of the fundamental ideas of the very same subject. For example, in geometry, the shortest distance between two points on a plane is a straight line. However, this is only if the case if the plane is flat. If a plane is non-Euclidian, which means that it is a curved surface, then the shortest distance between two points has to be a curved line, which defies THE most basic principle of geometry. As Craig continued the lecture, I began to grasp what he was discussing a little bit more, but I was still confused for the most part. It wasn’t until later that I was reviewing my notes with Brian that everything clicked. If you had told me at the beginning of this program that I would understand the ideas of relativity, I would have had my doubts. However, things have changed since the beginning of the Experimental Physics Academy. I have a stronger grasp on physics than I could ever gain after only a month of lessons.
Following Craig’s lecture was our guest lecture of the day. Today, Dr. Vijay Balasubramanian spoke to us about the biophysics of our brains. I find Dr. B’s background fascinating. He studied particle physics, cosmology, string theory, and several other areas of physics, but then decided to go into neuroscience. Although this was an interesting aspect of Dr. B, he was a very interesting lecturer as well. His style was energetic and he relied on volunteer participation, which is something I have not encountered in my few experiences with college professors and their lectures. The demonstrations he performed did help explain the material though. He gave specific instructions to pairs of volunteers that would be playing the parts of neurons in the brain. These instructions dictated how each pair would communicate with one another when a specific stimulus was applied. This demonstration was used to introduce us to just how the brain operates. This was part one of Dr. B’s lecture, which he called “How Brains Work.” Part two was called “Efficiency in the Brain” and covered statistics on how much energy and fuel the brain used to perform its work. The fascinating thing is, our brains consist of only two percent of our weight, but use up twenty percent of the metabolic load. It also uses only ten watts of power, which is about six percent the amount of energy per second of that used in a common light bulb. The third section of his lecture, “Can We Evolve to Be Smarter?”, covered the way we learn and how our minds came to be so advanced. Essentially, he informed us that our brains have (for the time being) hit an evolutionary roadblock. Right now, we do our learning through communication and synergy with others, not by enhancing how our brains operate. Our guest lectures continue to get more and more fascinating. I cannot wait to see what we learn about tomorrow.
After lunch we met in our special interest groups. Today, James took us to the roof of the Rittenhouse Labs to observe the sun through two different telescopes. We were actually able to see what we had been learning about for the past two days. The majority of our time on the roof was spent attempting to position the telescopes, one visual and one radio. Much to our surprise, it is not as easy to find the sun through the lens of a telescope as one may think. It actually took about twenty minutes to get a good image of the sun through the visual telescope. Once we had a good image, we were able to see a bright, orange ball emitting waves of heat. We were even able to get a view that was so magnified that we could see sunspots. Using the radio telescope was not easy in the slightest. It took a much longer time trying to get the telescope aligned. There were times when we would come close to getting the right angle, but then the graphs on the oscilloscope returned to normal after a few slight changes while the dish was moving. We spent over an hour trying to configure the telescope, when finally we got as close as we could to viewing the sun’s sound wave’s frequency output. Once we accomplished this minute feat, James informed us that we had just experienced several of the problems that come with using radio telescopes. There was a lot of interference from reflective objects in the area, which caused significant problems. The other major problem is the characteristics of the waves being used to receive the data. The waves are too spread out and are not specific enough to accurately pick up data from the sun, at least not from our location. Regardless of the problems, this experience was enlightening and I am learning through “failure.”
Our group of seven, Onur, Abheek, Alison, Julia, Fred, Brian, and I, decided to go to Center City Philly after our respective classes. We took the trolley and soon enough we were in the heart of Philadelphia again. We did not really have an agenda because we were just hoping to explore parts of Philadelphia as a group. We wound up getting some frozen yogurt, visiting the Comcast Building (which ironically looks like a phone jack), and eating dinner we picked up from a deli in the JFK Love Square. Our time in Center City was great, and it was definitely a different experience from when we rode a tour bus with Mr. Miranda three weeks ago.
My time here at Penn is dwindling. I only have ten days left in one of the greatest cities that I have ever visited. What is even more saddening is that I only have ten days left with some of the greatest friends I have ever made. Our time today at Love Square feels like it epitomizes the strong family-like bonds that we have forged over the past few weeks. We came together as strangers, but now we are the closest of friends and have made unforgettable connections. I pray that the next ten days are slow ones so I can enjoy the presence of my Philadelphia family that much longer.