"You Can't Do That"
Expressive 2010 2nd Place
Professor: Dr. Bryce Christensen
"You can't do that. You're only twelve." That's what my sixth grade teacher, Mr. Weaver said on an overcast day in the fall of 1974. I had just announced that I would construct a Diffusion Cloud Chamber for my very first Science Fair Project. As I recall, Mr. Weaver was the first person ever to tell me I could not accomplish something. My father, the man I respected most in life, never used such words with me. Dad had always told me to do things, period. He never mentioned the possibility of failure. Thus, I literally never thought of it. Consequently, I ignored Mr. Weaver.
My journey toward this discussion with Mr. Weaver began four years earlier. My father had purchased the fourteenth edition of The Encyclopedia Britannica, in an effort to, "slow me down." His reasoning was that this single purchase would take me many years to read. I was an inquisitive child, almost from birth, and discovered books at an early age. By the time I was six I read at high-school level and college level by age eight. Our family had a modest library of some sixty or so books, which I had completely read through before turning eight. Dad gifted me with the Britannica on my birthday that same year. I was fascinated, to say the least. It was like giving me my own library. That set of encyclopedias was indeed the beginning of my own personal library.
This collection of reference material appealed to me in ways no other volumes had. Bound in leather, they smelled somehow more important than the other books in our library. All dressed up, they had paces to go and wanted to take me along for the journey. Knowledge seemed to ooze from their stately bindings. They even looked more important, with their richly embossed covers. Lined up in chronological order, they were an impressive, orderly sight. Just gazing at them made me feel smarter. I opened the first volume and quickly began to develop a rabid appetite scientific knowledge of any kind.
Four years later, I was nearing the end of these magical, wondrous books, when I read about a man named Charles Thomas Rees Wilson, who had won the Nobel Prize in 1927 for creating the Wilson Cloud Chamber. This chamber was used to detect particles of ionizing radiation and map their path. My reading revealed that this was done by super cooling water vapor in a sealed environment in which a cloud was artificially formed from water vapor. When alpha or beta particles of radiation passed through this environment, they caused water droplets to form by ionization and left a trail. After further research, I discovered that Dr. Wilson's work led to the naming of "The Wilson Cloud," which occurs during the negative phase of a nuclear blast. My research described this phenomenon as a reduction in the air density during this phase (known as rarification), in which there is a temporary condensation of water vapor in the cloud that is visible after the blast. I learned that this is also referred to as a "condensation cloud."
It was the mention of radiation that caught my attention. We lived in Londonderry Township in Dauphin County, Pennsylvania. The Three Mile Island Nuclear Power Plant (TMI) was located about a mile and a half to the west of our house and had just started operations that year. The Cold War was in full swing, and we had nuclear blast drills weekly at school. Everyone knew at least a little about radiation. To those of my young age it was big, powerful, mysterious, and frightening. At the time, many people thought that an eventual nuclear holocaust was inevitable. But we also looked at nuclear power as the future, considering TMI was quite literally in our back yard.
I wanted to learn more about the future, nuclear power and the Wilson Chamber, so I began my very first research project. In the course of my studies, I found a book with instructions for building a smaller version of a Diffusion Cloud Chamber, which was actually developed by Alexander Langsdorf in 1936. It was a variation of Wilson's chamber using alcohol instead of water. I'm afraid I cannot remember the name of that book, but it probably still resides in the Harrisburg, Pennsylvania Public Library. I was intrigued. The school Science Fair was approaching and I had not yet chosen a project. I made the decision to build my own diffusion chamber. That, of course, was the easy part.
Despite Mr. Weaver's assertion that a twelve year old could not pull off such a project, I began. I needed dry ice to super cool my chamber, a concentrated light source (preferably one that created heat), something I could use as the chamber itself, pure alcohol to produce a cloud, and a source of radiation. I began to think this might not be as easy as I thought.
The dry ice was the easiest part, as it could be purchased from the ice cream truck that came by twice a week. I would wrap the ice in burlap I obtained from an empty chicken feed bag in the barn. Once wrapped, I needed to cut a hole in the top of the burlap to accommodate a wide-mouth, quart sized Mason jar I would use as the actual chamber. The book I was using as a reference suggested lining the lid of the jar with felt, but I decided to use crushed velvet instead. The light source suggested was a slide projector, readily available at school. I obtained the pure alcohol from the local hospital. That left only a source of radiation.
My father knew a man that was an engineer at TMI, so we consulted him. He suggested a mutual acquaintance who was a doctor at Harrisburg Hospital. Dr. Palmer was able to obtain permission from the hospital to loan me a small radioactive pill that was used in a medical procedure to locate tumors. Dr. Palmer explained that the patient would swallow the pill, about the size of an aspirin, and x-rays would be taken of the suspected area, revealing the tumor. This seemed an appropriate source of radiation for my project.
After a rather intense lecture on the safe handling of the radioactive pill, I assembled my diffusion chamber. The wrapped dry ice was placed on a small table along with the slide projector. I cut a circle of black velvet to fit inside the lid ring of the jar and positioned it there, gluing a circle cut from a paper grocery bag to the top of said ring. I did not use the lid itself, as metal vibrates and makes an annoying squeal when it comes in direct contact with dry ice. I then turned the modified lid ring upside down and placed the pill just inside the outer edge. I poured a carefully measured tablespoon of pure alcohol into the glass jar and swirled it around to distribute it as evenly as possible. Placing the lid ring on the dry ice, I inverted the canning jar and screwed it tightly to the ring. As an additional seal, I wrapped electrical tape around the lid, taping it to the jar. The light from the slide projector would heat the air in the jar and the dry ice would super cool it, hopefully creating a cloud. Now came the proverbial "moment of truth."
I admit to being slightly apprehensive that my chamber might not work. We turned out all the lights, except the slide projector and waited. A misty white cloud began to form almost immediately. Dr. Palmer, my father, and I watched closely. I believe we all held our breath, but cannot truly vouch for the other two. After about five minutes, faint, spidery lines began to appear on the velvet. We could actually see them move gracefully across the tiny field. We observed two distinct types of lines. The first were lines that started straight, then veered off at about a 45 degree angle. The second type where jagged and somewhat thicker and brighter than the others. Dr. Palmer explained that the first type of line showed something called "muon decay." He explained that a muon is an elementary particle, similar to an electron with a negative electrical charge. Dr. Palmer continued to explain that the second set of lines represented "multiple scattering," or low energy cosmic rays bouncing from atom to atom. It is impossible to describe exactly how I felt at that moment. It was my first real experiment, my first moment of discovery. I looked at my father and asked, "Does this mean I'm a scientist?"
He beamed back at me and said, "Yes it does, son."
I found out later that it takes a bit more than successfully recreating someone else's work to make you a real scientist, but I felt like one just then. I imagined the sense of discovery and elation I felt in at that moment was akin to those of the great scientists I had read about. I suddenly felt a more personal connection to Wilson, Langsdorf and others of their kind. I had used the scientific method for the first time. It would not be the last. Mr. Weaver was wrong. It turned out that a twelve year old boy could, indeed, build a functional Diffusion Cloud Chamber.
I set up at the Science Fair on the stage in the auditorium. The curtain was kept closed to create the necessary darkness. I had written a report, detailing my entire process, and drawn a three-section poster to illustrate the chamber and my findings. Mr. Weaver was one of the judges, and I eagerly awaited his visit. When he arrived, he looked over my written material and visual aids, pronouncing them worthy of an Honorable Mention. I asked if he wanted to see the actual chamber in action. He had apparently not noticed the sign I had placed on the door to the stage.
"You mean you actually built it?"he asked, somewhat incredulously.
I led him to the stage and demonstrated the mechanism. It was the first time I had ever seen Mr. Weaver at a complete loss for words. He simply stared at the chamber for a few moments, then turned to me and put out his right hand. I took it and shook it vigorously. He congratulated me and told me that I had taught him never to underestimate a student.
The experience of that Science Fair was the beginning of my personal love affair with science. I had discovered that it did not matter how young I was, or who I couldn't do it. Even a boy could achieve results in scientific endeavor. Scientific method did not discriminate against the inquisitive at any age. I thought of the great names I had read about, like Wilson, Langsdorf, Einstein, Curie, Edison, and so many others. Did anyone ever tell those great minds, perhaps in their youth, that they couldn't do it? Had anyone ever told them they were inadequate to the task? If so, I'm eternally grateful that they didn't listen.