So, what is the best order of topics to teach a physics 1 class (mechanics) in? If you look in most books out there there is a clear order that almost all of them go in, and have gone in forever.
That order is: Motion/Kinematics, Forces, Energy, Momentum, and Rotational Dynamics.
There is nothing wrong with the order of teaching the material. I did it for the first 13 years of my teaching. Then I went to a talk by another physics teacher and they suggested changing up the order, and putting forces before motion. The argument was that you teach about the push/pull concepts, and then lead into how that causes motion. Rather than teaching about the motion of an object and then talking about how that motion is created.
I thought, “Why not?” It sounded like a good idea so I tried it, and it was rough at first. I was so used to students understanding motion when talking about forces that I had to talk differently in class about what objects were doing. I couldn’t use words like velocity and acceleration right away because it hadn’t been discussed yet. So, it took me a semester, but I figured it out and I have been doing that for 9 years now. There is a lot I like about it. I get to spend more time on free body diagrams and net force equations because we are building the concept of forces, and leading them to what those forces do to objects. I think that has helped the students learn better what a force is rather than how a force is used.
It is far from perfect though. Since many students tend to enter my classes having had a physics class before in high school they already come with the motion stuff in their minds, and so they want to jump into things that haven’t been covered in class before we cover them, and often they say things incorrectly (misconceptions from earlier learning). But I work with it. Another issue I have run into is with regard to my online classes. Since those classes have online labs I have had a hard time finding labs that are designed to do a lesson on forces that doesn’t rely on the student already knowing about motion. I have had to give students equations without teaching where they come from so they can complete a lab with the statement “We will learn this equation in a couple weeks, but just use it.” As a result as I help develop an online course with a co-worker we are going to go back to the traditional order so we won’t have that issue.
Another thing I have done for most of my teaching career is move all of circular motion to the end. My textbooks intersperse circular motion throughout the semester when it meets up with a topic like: 2D motion, forces, energy, momentum. The books will tend to throw in a page or two of “Here is circle motion with respect to this big topic” and then move back to linear motion with respect to the next topic until the end of the chapter and then “Hey here’s circular motion again.” I always found that students would forget the circular stuff they learned from before and therefore you spend time researching that other stuff so you could cover the new stuff. So, I moved it all to end. My last few weeks of class is basically, “Hey everyone we are going to start the entire semester over topic wise but this time it is all with regard to circular motion.” Then we do motion, forces, energy, and momentum with regard to circular motion. It has worked out really well in my opinion.
There are other orders of doing the class as well. I knew of a teacher many years ago that started with energy, and then moving into motion and forces. I tried to figure this out one summer many years ago, but I couldn’t figure out a good way of doing it without a lot of the same issues I mentioned above about giving students equations so they could solve something without knowing where it came from.
So, as I move along in my teaching I find myself liking the order I do things in right now. It isn’t perfect, but is there really a perfect way of doing anything? If any of you are physics teachers and are teaching mechanics what do you think?
Hey Bro,
I have to admit that I (and most of my colleagues here) do the traditional order. But, there was a movement that you can still find in Germany, that put momentum at the beginning and made it the basis on which all of mechanics is built. Forces are then interpreted as currents of momentum (a Force “moves” momentum from one body into another). It caught on in some circles, but I think it’s complete crap.
Another interesting thing in Germany, is that static forces are often taught long before accelerating forces. So, you’ll do the force that stretches a spring long before doing Newton’s Laws. I also think that’s crap and always do accelerating forces before static forces. I think a force should make something happen before multiple forces balance each other out.
That’s my two cents.
Have a good day,
Your bro!
Those other methods seem way out there.
A force is a force right? And forces cause things to accelerate. So trying to separate that seems odd to me. And the current of momentum also is unnerving to me.