Bubble Chamber Exercises
Bubble chambers, and the images that they produced, were one of the first ways for physicists to "see" into the particle realm. The idea to create the bubble chamber supposedly came from a evening in a bar and a really creative physicist. Whatever the source of the idea, they became a dominant force in particle detection for many decades. The images also serve as an excellent tool for students to peer into the fundamental world and actually get a chance to see what is left behind when charged particles interact with their surroundings. Much like a plane flying high above in the air leaves a path behind for all to see in many instances long after the plane has left the air space. Particles interact with the liquid to leave amazing trails for all to see and identify. The thickness, the length, the starting point all can inform a trained eye so much about the properties of the particle. With the use of a magnetic field and the resulting curve of the particles, even more can be learned...properties such as momentum and charge can be determined by just about anyone with a little knowledge of physics.
This is what makes them such an excellent starting place for any unit on the intriguing subject of particle physics! Anyone can look at the image and identify interesting events...you do not need to be a particle physicist. The fundamental laws of energy conservation, charge conservation, and momentum conservation can all be displayed through bubble chamber analysis. The behavior of charged particles in a magnetic field will also be used to help identify the various particles that are streaming through the various images. Use bubble chamber images as a review assignment in your classical physics study or as an introduction to your unit on magnetism, they can serve a variety of educational purposes and provide a quite the unique activity for your students. Or, you can just use them, like I do, as the start of your particle physics unit. What I have listed below are a few of the exercises that I have used to help introduce the wonders of bubble chamber images and, of course, particle physics to my students over the years.
Bubble Chamber Detectives This is the exercise that I currently use with my students. You can use as many of the images as you would like and modify the assignment to fit your needs. By the time the students have looked over a five or so of these, they really do get a sense of how to analyze these images. I have many versions of this exercise and I borrowed the images and the idea for the exercise from Seeing Particles by Peter Watkins.
Bubble Chamber Answer Sheet This is the sheet that I ask the students to complete as they identify the various bubble chamber events.
Bubble Chambers Momentum Many years ago a new textbook called Project Physics was introduced and one of the sections that was included was all about particle physics. Many of the exercises involved using bubble chamber images. When I came across this book, I quickly edited a couple of the exercises to make them a little more high school student friendly and tried them out on my students. This activity and the one below are the two that I have used most frequently. Due to time constraints, I do not use either of them anymore. When I teach magnetism and the relationship between centripetal forces and magnetic forces, I do bring out the template and have the students take some measurements. It works really well! These two activities have been modified with approval from an author of the textbook.
Bubble Chambers Energy As mentioned above, depending on if you want to spend time on momentum or on energy conservation, these two activities can really work. They do use relativistic calculations that I do not go into great detail about...I just mention to my students the source of the equations and have a brief discussion with them about their relevance. This activity is a little easier than the momentum one and I often used to do this one first and then the momentum exercise as a review before the quiz.
Analyzing Bubble Chamber Images Tutorial Powerpoint Looking for a powerpoint to help guide your students through the analysis of a bubble chamber image? This may be helpful...simply put, this is just the introduction to the Bubble Chamber Detectives in powerpoint form.
CERN HST/ITW Programs Every year, CERN hosts a group of high school teachers from around the world. The opportunity allows teachers to learn more particle physics and to create curriculum related to particle physics.
CERN Bubble Chambers CERN has its own website dedicated to bubble chamber analysis. Includes tutorials, links to images, and teaching materials.