Sometimes students think that units are for me. I get all excited about them writing down and checking their units. "It's a chance to catch your mistakes," I say. "It's a chance to really know what the units in the answer are," I say. "It can tell you how to do the problem!" I exclaim. "Come out to the coast, we'll get together, have a few laughs," I say (wait, that wasn't me).
Anyway, the students that see it, buy it, or try it... succeed. Those that refuse... generally struggle (certainly, they struggle more than they need to).
I get that you might (should?) need more than my word to buy into something. That's where the logical argument and all of the times that we've seen it work in HW and class should come in. If that didn't do it for you, then how about this?
On our first assessment covering amplitude of oscillations, I asked this question, after showing a video of a lab cart oscillating with the help of two horizontal springs. They had already determined the amplitude at my request, and had stopwatches available.
"How far would the cart travel in a year, if its amplitude remained constant?"
Yes, it's not terribly 'real world,' because the cart certainly won't go that long, with all of those juicy damping forces around. That's OK - we're just stretching our legs a bit.
What I like about this is that it connects period/frequency and amplitude. That, and we'd never done anything like it before. There's always something new on a physics test, but you can apply old concepts to figure it out. That's just... how physics works. If you're waiting for me to list all of the "types of problems," then you'll be waiting a long time. The concepts that we apply to this multitude? Well, you can list that pretty easily (it's the list of standards for the term!).
Anyway, here's where the units hit the road. Folks that have taken my advice and really gotten into checking their units had a real advantage:
Not only did unit-checkers get all of the more familiar applications of T, f, and A correct, they also all got this entirely new question correct!
Yeah, all of them. Here's a chart showing how folks that check their units did on the question, as opposed to those that didn't: