### One question...

do sixth graders need to be able to

I am leaning towards minimizing the math in favor of the idea.

*calculate*mechanical advantage? Or is it enough for them to be able to look at a simple machine and explain how it changes the force needed, distance over which work is done, or direction in which force is applied?I am leaning towards minimizing the math in favor of the idea.

## 6 Comments:

Go for it!

Understanding a process is more important than calculating an answer.

It does not help if they know that 1+1=2 only to have them ask you what is a 2?

Ms. Frizzle writes:

Or is it enough for them to be able to look at a simple machine and explain...?

This is why engineering schools are dominated by Asian students who know the theory AND the calculation process.

You do the idea......can the math teacher integrate those type of calculations into what he/she is currently doing with the students?

My high school students are shocked...simply shocked....when I ask them to do calculations relevant to what they JUST LEARNED in chemistry class.

Anywho, to answer your question....I don't think its quite enough to simply understand the idea. I would imagine some kids might understand the idea better if they have the numbers to really show how much of an advantage there is for a given set up.

It all depends on your learning objectives of course. But I do think, as Ms. Chalky Talk said, that it can be useful to some students to have the math. It's all a question of how your mind works. Some kids just get physics better if they can conceptualize forces and work into equations and maths.

Perhaps you could explain the maths to them but not make it an expectation on a test?

I've been a long time lurker, but I've been tempted by your recent physical science posts to come out into the light. So, here goes. . .

I have to honestly say that as a physics major and astronomy phd, I had never heard the term "mechanical advantage" until I happened to be volunteering in a high school physical science class last year. Maybe I don't hang out with enough M.E.'s, but I just don't see the importance or utility of the concept. It's just dividing two much more important numbers, and then sticking a big name on it.

It seems to me that if you're going to do calculations, spend your time on calculating/manipulating the original forces involved (something the students are more likely to be asked in a future class), and then wave your hands at the "mechanical advantage" stuff. However, not knowing what your actual lesson looks like, I can only wave my hands at what I mean by that.

(Oh, and I'd be more than happy to learn how mechanical advantage is a very useful concept to teach, and where it might potentially lead, if someone has good ideas.)

As far as minimizing the math goes, I am a huge fan of starting rigorous conceptual physics very early. Getting more kids interested in physics through a larger variety of teaching methods would be an amazing thing. However, if any of your students choose to become physical scientists/engineers in the future, they're going to be judged by an old guard that cares much more about how well students can calculate/manipulate equations, that won't at all be related to the work that they might end up doing as future scientists.

Wanting lots more kids to learn, while still preserving the success of some is a tough situation that I don't know the answer to. Maybe someone else does.

By the way, how did your problems with the normal force turn out? I'm very interested in hearing that.

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