Introduction
What is physics?
The big questions of physics are the big questions of the universe: what is it? Why is it there? Did it have to be this way, or could it have been different? Physics uses mathematics, experiment, and explanation to come to terms with things that are almost unimaginable in scale. The Large Hadron Collider in Switzerland is smashing particles called protons into each other at speeds very, very close to the speed of light, and watching very closely to see all the debris that come out of the collisions. They are a little bit different every time, due, apparently, to some randomness in the ether.
What do they do, when they track these debris? They trace backward, finding that the debris they see at the detectors (which, obviously, can't be quite at the location of the collisions), have moved in straight lines outward from previous collisions -- that themselves traced backward into the singular moment of the original collision. They calculate the momenta of these particles, and make calculations about what kinds of interactions could have caused those particular particles, with those particular momenta and directions to have been produced. And every once in a while, they find that they cannot explain the traces they see using any of the known particles, or any of the known ways that those particles can interact with each other. And if they see one of those strange events enough times (so they are sure it wasn't a fluke of a mishap with the detectors), and they can find someone who can suggest an explanation, they propose: "HEY!! We've found a BRAND NEW particle!! No one has EVER seen this before. We are BAD-ASS!!"
The stakes are very high. Billions of dollars. The careers of thousands of scientists and engineers. But at heart, what they are doing, is not so different from a traffic engineer -- surveying the scene of an accident, photographing the final locations of the vehicles, the specific damage done to the bodies, the tracks on the pavement, to determine who was speeding or which vehicle crossed the center-line. Except that sometimes the answer is: "A Higgs particle suddenly came into existence and pushed Car number 2 into the path of Car number 1."
Physics I teaches you the basic principles, techniques, and thought processes necessary to understand a crash scene or a particle trace from the LHC. Along the way, you learn how to analyze building components for stability, the claims of "green" energy purveyors, and the motions of spinning things. You'll also practice developing explanatory models for different phenomena, and testing those models using experiments you will design yourself.
Many people dislike science and math because it makes them feel stupid. Because scientists are unusually good at saying "You're wrong!"
If you learn nothing else in this class, I want you to learn this: Being Wrong is Good. You cannot improve unless you hit the wall of your current limitations. Being wrong is a sign that you've hit one of those walls, and is therefore a signal about where you need to work. The goal is of course to become not-wrong, but you cannot get there without going through some wrongness. My job is to help you find those limits without hurting you, so you can push them back.
I believe that this is true of everything worth doing, but it is particularly clear in math and science, where the whole process works by proposing models and testing them. A model cannot be a good model if there is no way that you could discover it is false. People have an unfortunate tendency to seek out evidence that supports their current belief, missing the evidence that contradicts it. You are much more likely to avoid being misled by forming a prediction/model/explanation/etc. that you think is good, then writing down what kinds of evidence would show that you are WRONG, and then to go looking for that CONTRADICTORY evidence.
Alright -- so enough of that. Now I'm going to give you a test! Yes, a test. The point of this test is to help me ensure that I'm actually teaching you something. I'm setting up an experiment, and my hypothesis is that you are going to learn a lot of mechanics this term. That's what I want to have happen. So I've identified a lot of things that would count as evidence that you have NOT learned any mechanics, and I will test you on them repeatedly through the term. Your grade will depend on convincing me, over and over again, that you have learned specific concepts and skills in mechanics. The more things you try to convince me about, the higher your grade can potentially get.
But for my tests to work, I have to have some information about where you're at right now. Because one possible way that I could be misled is if you happen to ALREADY know a lot of mechanics. So this test is designed to help me find that out. It's multiple choice, it's hard, and you should do your absolute best on it -- think about the questions, they are designed to be tricky. When you are finished, bring it up to me, and I have an assignment for you to work on for next time, that you should get started on.
The Course
The class is not going to be easy. I'm not saying that to frighten you, I only want to be as honest as possible. It will require work. A university course expects that you should spend 1-2 hours outside of class for every hour in class -- which corresponds to 4-8 hours for the lecture portion of the class, and another 3-6 hours for the lab. That's just how much time it takes to process and learn so you can expand your skills and knowledge. So I'm giving assignments that will take up a chunk of that time, and expecting that you will fill in time as needed to keep up. I know that many of you have jobs and other expectations, and I respect that, but I still expect some comittment from you to get the most possible out of this class. I promise that I will never waste your time, or give you work just to fill in the time -- it will always be carefully planned to help you get as much as possible out of your investment.
The grading for the class will be different from what you've probably seen before. The lion's share of your grade will come from a long list of skills and concepts that I've identified as being particularly important. You can find the list on the syllabus, on ulearn, and on the course blog at markbetnel.com/genphys. You should read that list frequently. I will give you quizzes, tests, and assignments that are designed to test those skills, and give you scores on a 1-4 scale that reflect your level of proficiency in each one. If you get 4's on 90% of the skills, you will get an A for the standards mastery portion of the course. If you get 4's on 80% of the skills, you will get a B. If you ever get lower than a 4 on a skill, you are expected to make an effort to improve your performance on it. Once you convince me that you are going to do better on a new attempt at that skill, I will give you a new chance to prove it. Your scores in the gradebook will reflect your highest level of performance on each skill (so there is no cost to trying multiple times).
You should also try to identify skills that I have not mentioned -- if you can convince me that there is an important skill that is not on the list, I will create an assessment for that skill and give you a chance to prove your mastery of that as well. So there is an opportunity to take control of what you will learn and master in the course, and an incentive to reflect on what you have learned and on your grades.
The rest of your grade will come from expected sources -- quiz scores on your first attempt, the final exam, homework, attendance and participation, etc.
Homework
- See Homework1
- You should expect to be able to complete similar problems in a quiz situation next time.
- You should read chapter 6 in the book to help you in doing these problems.