As for the oscillation frequency section- I agree it’s a separate concept, and I thought about either leaving it out entirely or doing a separate post about it. In the end I included it because it was included in the “traditional” lab I used as a jumping off point for this post. In the classroom I think I’d give it some separation from the first part of the activity- though I do think you could flow fairly smoothly from the first investigation (Hooke’s Law) to the second (simple harmonic motion).

While I was reading over your post, I thought of this one:

* Given a spring, ruler and three 20g masses, predict the length x that the spring will stretch when a mass of 15g is hung from it. Justify your answer using a careful analysis of data that you collect, including graphs and equations.

This covers 1 and 2 of what you’d like them to understand, because they’re going to have to verify that the relationship between force/mass and the displacement is linear, model that line as a best fit line/equation with a specific slope for that spring, and then interpolate to find the desired length.

If you have time, you could give them little guidance on how to do the analysis and then follow this exploration with a short lecture on Hooke’s law then have them repeat the lab but with a slightly different question:

* Given a spring, ruler and three 20g masses, predict the length x that the spring will stretch when a mass of 120g is hung from it. Justify your answer using a careful analysis of data that you collect, including graphs and equations.

Same procedure, so students who didn’t do a deep enough analysis can improve their write-up, but advanced students can also explore the difference between interpolation and extrapolation, and start to intuit the idea of an elastic limit.

The oscillation frequency/period of the spring seems like such a separate concept, I’d leave it out of that first activity. I like the way you have it in “Fifth”, but I think the leap to drawing a force diagram for the spring might be too big for most students; I’d want them to notice it’s not just a systematic error in the period vs mass relationship, it’s an error of *missing mass* (observed periods are longer than calculated/predicted periods, therefore either k is wrong — unlikely — or the oscillating mass is bigger than what we’re using to calculate period). What mass could be missing from our calculation? What else in the system that is oscillating has mass? And then go on from there as you describe.

What do you think?

BTW, you wouldn’t be the first person I’ve met through the Twitter to mistakenly refer to me as Will or Willy. Guess that’s what I get for having a long last name and not thinking too hard about creating a shortened version of it.

I meant Ben! (I was thinking about your Twitter handle, @WillyB.) Sorry, bud.

Frank

Sounds like you’ll do just fine next year!
Frank Noschese´s last [type] ..My Vision for a Physics iBook

Thanks for the kind words. I’ve seen via Twitter that you’ve started the project- I’m glad you found the pipe insulation posts helpful. I’ve been meaning to write them up for a looong time. Let me know how you managed your space issues- in all likelihood if I run this project in the future I’ll have space issues as well.

My advice for you (or any relatively new teachers) is to not be afraid to try new projects and activities. I think often projects get nixed early on by teachers who are afraid they’ll take too much time for too little value. On the face of it these roller coasters could fit that category. Try out a new project or two each year. Some will have too little value for their time, but as you progress you’ll get better and better and figuring out how to improve projects and you’ll find most projects will succeed. After a few years you’ll have plenty of great activities and projects to choose from.