I took three physics classes through a local community college last semester. From how the content was presented in each class, it would be fair to say Physics is primarily concerned with learning a set of equations and then figuring out which equation you need to use in order to find the right answer.

This is *not* a very useful skill. People wiser than I have pointed out similar things. So why, in high school and introductory college physics classes, do they lean so heavily on "learning the formulas?" Here are the two arguments I've heard the most often:

#### They'll need it in college/their careers

It could be argued, perhaps, that it *is* good preparation for students who will be pursuing engineering or scientific careers- after all, they'll be taking college classes and graduate classes and probably use a couple equations during their careers. However, there's a big problem with this line of thinking. Are all the students in a high school physics class there because they're planning on becoming scientists and engineers? A few, maybe. Most of them will not- and that's OK, but this realization should cause us to rethink how we present the material.

#### The equations explain the relationship between variables

I'm sympathetic towards this line of thinking (more on this later)- but not enough to think it's valid. Whenever I hear this argument the first question that comes to mind is "Is this the best way to explore those relationships?" In my experience, students who have struggled understanding physics often did so because they couldn't make sense of what the equations actually describe. Given an equation and all the variables but one and they'd be able to work though a problem, but they weren't understanding *why* that answer makes sense and any further obfuscation of the problem quickly threw them off track. I agree that the relationship between variables is an important bit. I don't believe that equations clarify that relationship for the vast majority of students.

#### How I'd like to teach physics

Understanding the relationship between variables, in my mind, is the key to a useful understanding of physics. If I push twice as hard on this shopping cart, what happens to the cart's acceleration? That's a tangible situation that is easier to understand than simply throwing out * F = ma* and hoping students figure out that relationship on their own. Further,

**students should discover these relationships**. Give students some equipment and tools and have them measure what happens to an object's acceleration as they apply more or less force on the object (some tracking software would be really handy for this). Then have them apply the same force but change up the mass. Chances are pretty good they'll be able to discover

*on their own. Chances are they'll have a much better conceptual understanding of what*

**F = ma***means at this point than if you simply gave them the equation and had them do some problems. Or if you simply had them prove the formula is correct in a lab.*

**F = ma**#### Why it matters

- I believe the focus on relationships promotes a better conceptual understanding of physics- the students can more effectively internalize the way the world around them works. A populace with a healthy baseline of physics knowledge could prevent silly and potential harmful pseudoscience such as magnet therapy from becoming an issue.
- There's been a focus on increasing interest in STEM careers- and a special focus on recruiting women and minorities into STEM fields (see this White House press release). An equation-focused physics curriculum can seem intimidating to students. A collaborative, constructivist approach can be perceived to be less intimidating and more welcoming (I'd recommend giving Episode 32 of the Shifted Learning podcast for some interesting bits on gender issues in STEM).

#### Modeling Instruction

I don't have much experience with Modeling Instruction, but it seems from my reading that the instruction I've been describing is essentially what it is. As a bonus, it's well developed, well researched, and well used instructional method to improve students' ability to construct a better understanding of the physical world around them.

If you're interested, I've found both Kelly O'Shea's series on model building and Frank Noschese's primer to modeling instruction to be great resources. Check their blogrolls for even more good stuff from teachers using modeling.

As I look forward to potentially teaching physics next year I want students who take my classes to come out with a lasting understanding of the topic. I don't want them to half-heartedly memorize equations that they'll forget two weeks after we finish a unit. I'd like to teach for all the students, not just the future scientists and engineers.

Hi Will,

Sounds like you'll do just fine next year!

Frank Noschese´s last blog post ..My Vision for a Physics iBook

Ben,

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

Frank

Thanks! Here's to hoping the job market for Physics teachers is full of openings and low on applicants.

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. 🙂

Ben,

I hope that you will try your best to take a Modeling Workshop this summer. Modeling Workshops in high school physics, chemistry, and/or middle/high school physical science will be offered in many states. Stipends are available at some sites. Most workshops are two or three weeks long.

Websites: http://modeling.asu.edu/MW_nation.html , http://www.ptec.org/pd Click on Modeling Workshops

@

Jane: I sincerely hope to attend a Modeling workshop this summer. It's definitely on my short list of PD experiences to get to. Thanks for the info & links. If it even comes close to working with my schedule & budget, I'll be attending a workshop this summer.Ben: Did you find time to take a Modeling Workshop in summer 2012? If not, please try in summer 2013. Many, many teachers say that it is the BEST professional development of their entire career! Workshops are described at http://modelinginstruction.org, and http:///www.ptec.org/pd . About 50 are offered each summer, in physics, chemistry, physical science and biology.

Patrick uses the quadratic frmluoa, which ALWAYS works for ALL QUADRATIC equations.there is actually an easier (more like faster) way to solve this, but with the same idea as Patrick's.You want to find the "zero" or "root" of h = -5t^2+110t because that's when height = 0 (it hits the ground)height = 0 when it is first launched from the ground or it hits the groundso h = -5t^2 + 110t = 0factor your height function0 = (-5t)*(t-22)* means multiplytreat each product of isolated variable t as its own equation:0= -5t > so t = 00 = t 22 > so t = 22solving for t gets you t = 0 and t = 22t = 0 is when you startedso the rocket returns at t = 22 secondsReferences : Was this answer helpful?