Culturalization(?) & Meaning

I’m not even sure if that’s a word. Just checked, it is. I’m noticing something big about my students as I’m grading quizzes on Momentum. Something about using conservation of momentum is making it clear which students are memorizing formulas vs. understanding the basic idea of conservation.

Here’s where I’m noticing something radically different than I saw at my last school: My perception right now is that I have more female students memorizing than male students. I have several male students that I know are grappling with the meaning, but only a few female students that consistently grapple with meaning. This is not how I remember my physics classes in my previous school.

I have no data to back this up, but my current perception is feeding into the notion that any gender difference in any field is more cultural than anything else. And I don’t like any culture that favors any level of memorization for anyone over grappling with ideas and finding meaning on your own.

Document the Positive #3

Another thing that I did well this year, was getting guesses before we delve into the problem, or find a solution.

Asking students to put down a guess did a whole lot of things, all informative and only some really helpful.

1)  It revealed to me that they had never considered using their own experience to determine if an answer is reasonable.  I spend a substantial part of the year trying to divorce them from the idea that the teacher has a magical ability to know the answer.  At first I would just walk through their math and reasoning.  Over the last month, I’ve started thinking out loud some estimation calculations (things like g = 10 m/s/s, round everything off to 1 sig fig, do the mental math out loud)

2)  I found that they had never gone through the thought process of determining a range of reasonable answers.  Even the Hi/Low was a real struggle at first.  I have to think this one through a bit more, because I pretty much limited myself to talking about more/less than 0 most of the time.

3)  One thing I should have done, is to create a page in their notebooks of useful quick and dirty conversions.  Things like 60 mph ~ 30 m/s.  You can roughly double any speed in m/s to get mph.  10 Km  = 6 miles.  2.2 lbs = 1 kg, but also .5 kg ~ 1 lb.  I think those might have helped.

4)  At the very least, by forcing a guess I was able to find out if anyone in the class had a logical thought process.  I could toss out a ridiculous number and the students would all guess around my number.  I did this with estimating how far up a ramp a cart would roll during a gravitational potential energy / kinetic energy demonstration.  All of the guesses in the first situation scattered around my ridiculous guess.  In the second situation they jumped all over the map (at least they didn’t trust me anymore).  In the third and last situation, they did the calculations, and adjusted for friction.  Just by their guesses I could assess how much they understood about that situation.

5)  The last part is that forcing a guess (along with a diagram) forced them to think about a physical situation – or at least read the problem – before jumping off into math world.  Also, having that guess to check against caused more students to bring back that answer from “math world” and see if it actually fit before moving forward.

Document the Positive #2

I made a promise to myself that I would document positive things this entire week.  Today I’m going to focus on experimental method.

At the beginning of the year, I changed my approach to uncertainty and measurement.  I just wish that I had continued the push well into the year.

In the past, I’ve done this great lab on measurement that I got from my cooperating teacher during my student teaching.  The students are asked to measure the length and width of a lab table using only a piece of string.  The point is that their measurement has a large uncertainty due to the quality of their tools.  Then they calculate area to see how uncertainty in measurements propagates.

In previous years, this quickly turned into the rules for significant figures.  During the lab, I made them keep writing all measurements as:

3.4 +/- 0.1 strings

But in honors physics I jumped to just using significant figures too quickly.  I assumed that my honors students were higher skilled than my general physics students (whoops!).

The major benefit was that uncertainty in measurements wasn’t just “our result is wrong” or the useless “human error.”   We changed our language so that uncertainty was in “human hands using a cell phone timer” or “normal eyesight and a meterstick.”   Therefore, it was easier (although still difficult) for students to see slightly different numerical results as equivalent.

So what I’d like to do next year – to push the uncertainty of measurements throughout the year, is to require the plus/minus on every lab.

I’m also thinking it would be nice to have a measurement problem on quizzes/tests.  Something where I’ve taken measurements, and the students need to apply their calculations and provide a prediction along with uncertainty.  Well, maybe that might be a bit much.

Right, so that’s something I’m proud of.  It set me a solid week behind the other physics teachers, starting a slow drift resulting in my being 1-2 units behind the other teachers at the end of 3rd quarter.  I think the ability to compare real measurements is worth the time.

Document the Positive

I’m approaching the end of the school year and I’ve been pretty negative almost the entire time.  Because I don’t know where I’m teaching next year (due to my spouse’s career), there are a lot of changes that I didn’t make based on my perception of investment/return.  Those problems have occupied my mind, pushing out the problems that I have solved and addressed.  So I’m going to spend this week documenting one thing per day on this blog that I changed this year for the positive.

Today I’m going to talk about less structured problem solving.

In the math & physics blog-o-twittersphere there is a strong discussion about how to make our students better at applying this wonderful math that they’ve spent so long learning.  I’ve even noticed this in my own teaching, how a slightly novel situation throws my students for a complete loop.  If the information in a problem was not explicitly listed, they weren’t sure where to start.

In the past week, I’ve noticed that this is no longer the case.  I can’t take all of the credit, but it seems reasonable that certain teacher moves contributed to their increased flexibility.

1.  From the beginning of the year, I refused to nail down a particular explanation or calculation as correct.  It was always:  “What assumptions are you making?”  “What Jane said seems to be assuming X, is that a valid assumption?”  “I can’t say if that’s correct, but I can listen to your thought process and tell you if something doesn’t match up.”  I also tried to remove myself as the expert with all the answers, going so far as to not even know the final calculation so I couldn’t react with body language.

2.  Presenting situations first with a bare minimum of information.  And by bare minimum, I mean just enough to understand the physical situation, but not enough to make all of the calculations.  Students are then prompted to ask for the information they need.  I could always add in more prompting or help in figuring out what information they need later.

3.  Presenting situations with an excess of information that is unnecessary.  This was really eye-opening for students when they were doing gravitation problems where I would give them planetary radii and orbital radii and they had to figure out which radius/distance to use.

4.  Forcing them to draw diagrams and list variables.  I taught them to do this from the beginning, but many students refused.  “Drawing a diagram is too much work!”  They were very focused on the step immediately in front of them.  I -think- many of them weren’t thinking 2-3 steps ahead in a path to solutions.  Once I forced the issue and refused to grade their work unless they drew a diagram (I offered to help them figure out a diagram if they didn’t know what to draw), the quality of work and accuracy improved drastically.

DISCLAIMER:  I’m not saying I came up with any of this, or that anything is groundbreaking.  I just wanted to make sure I have a record of things that I’m doing that seem to be working well.