Conservation Laws Exercises

"Every process that is not forbidden, must occur."

We all know about the conservation laws of classical physics: conservation of energy, momentum, and charge. If you include the conservation of angular momentum and you pretty much have much of the rules that govern the world of classical physics. But, do those same laws govern the world of the fundamental, or are there actually different rules or does particle physics combine the old and the new? As physicists started probing the fundamental world, they soon realized that there were too many particles that were not following the rules. So, like any great scientist you have to make up some new rules! These "new" rules have been shown to hold true in all subsequent particle interactions and decays and now are just as important as the classical ones to the particle physicists. From conservation of baryon number to conservation of strangeness and many more, there are now many more conservation laws that describe the interactions of the particle world. The exercises that are listed here all involve in some way an exploration into the conservation laws that govern particle physics. Use them in isolation or use them as part of your unit, they will all provide a way for your students to learn that there are more rules out there than just the classical ones. And, when you find something that does not make sense, make up a rule!

Conservation Laws Exercise I use this exercise as an inquiry activity for my students. I break up into three parts. The first part I have the students do independently, typically as a homework assignment. The next day in class I ask them to form groups and discuss their individual work. As a class, we come up with the five rules that govern the particle events. Finally, for homework I ask them to complete the assignment. It is not easy and many of the students will come in on the first day with blank sheets. When they get into their groups, the conversations are interesting and you start to get your first sense as to how much fun particle physics can be. Your students will be talking physics and using words that only they really understand!

Examining Particle Reactions I I use this exercise to allow my students to put into practice what they have learned about the conservation laws and how they apply to the particle interactions and decays. They will need to use the Standard Model Particle Data sheet to help with the identifications.

Examining Particle Reactions II Similar to the final section of the Conservation Laws Exercise, this exercise will provide more practice for your students in determining the possibility of a variety of particle decays.

Standard Model Particle Data All the data that you will need to know about the Standard Model particles.

Determining the Mass of the Z Boson Investigation I wrote up this activity as an alternative to the QuarkNet created activity called The Mass of Top Quark Investigation. Using actual events from the ATLAS and CMS detectors, your students can actually determine the mass of the Z boson. Works really well as a one day class exercise...I have the students work independently and then enter their Z boson masses as they find them into a projected histogram for the entire class to see. The next day we discuss their findings and compare to other classes and the accepted Z boson mass. The images for the activity can be found at Determining the Mass of the Z Boson Images.

Introduction to Determining the Mass of the Z Boson Investigation This investigation can be used as an introduction to the Z Boson Investigation. Your students will need to understand the conservation laws and have a pretty good knowledge of particle physics in order to work through this independently. Could be used as a class discussion before introducing the Z Boson Investigation.

Determining the Mass of the Z Boson Online Exercise This is the online version of the Z Boson Investigation. A slightly different presentation of the exercise, but still has the same ultimate goal of determining the mass of the Z boson.