Physics & Physical Science Demos, Labs, & Projects for High School Teachers

year in review 2012It’s been a pretty mundane year.  No drama, no great leaps, no alien invasion or Mayan apocalypse, pretty much the same stuff, new year.

Hey, this would be a good time to assess the pro’s and con’s of standards-based grading (SBG) in my physics and calculus classes.

The Good

My spreadsheets are working great.  It may seem like a small thing, but it isn’t.  A well designed spreadsheet is the key to keeping SBG running smoothly.

It’s nice to have a bank of questions and quizzes at the ready.  My first year of SBG was non-stop quiz creation.  Now I need to make maybe one or two new physics questions a week.  I probably have 300 individual physics questions divided among the C, B, and A-level quizzes.  The hard work is done, weekly quizzes cause me no stress at all.

The kids all love standards-based grading.  One of my students told me she couldn’t imagine taking calculus using a traditional grading system.  The kids are all on board.

The Meh

Probably the biggest problem with SBG is determining who is in danger of failing at the interim report.  Half way through the quarter, the class average is in the 50’s or 60’s.  One of my students emailed me over Christmas break asking me to call her mom.  She is an A student, but her 60 average at the interim was going to get her grounded for the break.  This is after I sent home letters at the start of the year and at the interim explaining why the averages are low.  The kids who plan on failing just don’t come in to take quizzes or get help.

I’ve noticed that the lack of testing pressure has caused the kids to put off studying for the weekly quizzes.  Now they look over the problems right before class.  It’s hard to determine if this would be any different with traditional grading; this year’s class is academically quite lazy.  They have been warned, there is no curve.  They can all get A’s and they can all get F’s.  Amazingly, it will be a normal distribution curve.

What’s Next

I’ve been thinking about what changes I would like to make.  I’m considering a small change to the calculus grading system.  Right now it takes two correct problems to master a concept.  The first perfect quiz gives them 40/50 points.  The second moves that to 50/50.  I’m thinking of scoring the second 45/50 and the third 50/50.  My concern is that they are earning the label of “mastery” before they really get there.  On the other hand, the kids probably understand the material so much better than they would through traditional grading.  Any thoughts?

One little thing I would like to do is color code the physics quizzes.  I’d like to copy all the C-level quizzes onto a pale yellow or pink paper.  Maybe a light blue for the B-level, and leave the A-level quizzes white.  The colors would give the student and me a quick visual check of everyone’s progress.

Considering SBG?

If you are, I am willing to share everything I’ve created; my spreadsheets, quizzes, experiences and ideas.  Just ask.

I had been using the archaic ticker tape device to do a lab comparing acceleration to constant velocity.  Yawn.  It was not my favorite.  It wasn’t anybody’s favorite.  Let me be clear – it was boring.

I recently picked up a Sony Bloggie camera on eBay for about $50.  It’s the same thing as a Flip camera. Make a video, flip out the USB plug, transfer file.  It’s just that easy.  I set up a backdrop of black paper from floor to ceiling.  Kids got on a desk and dropped things.  Everybody had to drop a golf ball first.  A golf ball will fall pretty close to an ideal parabola, very little air resistance over such a small distance.  After that, they could drop anything that wouldn’t break.  I have soft squeeze balls and practice whiffle golf balls, superballs and paper balls, and best of all, a coffee filter.  The coffee filter is a must, it reaches terminal velocity almost instantly.

We are using Logger Pro software from Vernier.  I suppose you could use Tracker, but I have Logger Pro and know how to use it.  In Logger Pro, we insert the movie file and then use the tools to place a dot on the object as it drops.  The software advances the frame, and in a few minutes we have a synched up video, graph and data table.  The software allows the students to quickly see how the slope of the distance vs. time graph changes.  They can replay the image and watch their data points in action.

Click for larger image

I have them use a quadratic curve fit to calculate the actual acceleration.  Then the kids create a second curve and override the fit value with g/2.  That puts the expected acceleration curve next to the actual.  The effects of air resistance are instantly visible.

We just did this lab for the first time yesterday and today.  Give the kids time, it’s going to take them a couple class periods to make this all happen.  Initial feedback has been good.  I think it’s making sense to them.  They can see the effects of acceleration.  They can clearly see terminal velocity.

Here is the lab they used.  I expect there will be some changes.

Free Fall Lab

A few weeks back, my principle asked me to talk to the faculty about my experience with Standards-Based Grading.  Our professional development begins this week and I will be presenting on Tuesday (8/28/12).  This is my first public talk on the topic, I hope to present a more refined version of this talk at a conference later this year.  The slides aren’t glamorous and it’s a lot wordier than I like, but it feel the PowerPoint needs to stand on its own without me talking over it.  I’ll embellish with anecdotes and energy.

There are some comments in the note section on some of the slides, so you probably want to download the slide show rather than just view it directly on Dropbox.  I’ve also included an annotated set of spreadsheets that I will be using during the presentation.  Hover over the commented cells to see my thoughts on the patterns that show individual student development.

https://www.dropbox.com/sh/s9f2r2jjko65ehs/5ooodjg10L

I would really appreciate any feedback, negative in particular.  If you find slides are unclear, confusing, any typos, or if I’m you think I’m missing something, I need to hear from you.

My father just sent me this TED Talk.  He doesn’t read my blog and didn’t know about the other TED Talks I posted.  This one is a little different, Ramesh Raskar from MIT has developed a camera that can slow motion down to the point of being able to see a pulse of light travel.  You just have to see it to believe it.

And in case you aren’t seeing the embedded video:

http://www.ted.com/talks/ramesh_raskar_a_camera_that_takes_one_trillion_frames_per_second.html

I do.  They frustrate me a bit because there are just so many and I don’t know most of the speakers.  You can spend an evening jumping from one talk to the next.  I prefer recommendations, here are two I recommend.

The first talk is by Dan Meyer of the dy/dan blog.  His blog was the source I used to get started on Standards-Based Grading.  Plain and simple, this talk is an eye opener.

The second TED Talk is by Simon Sinek.  His talk was recommended by Frank Noschese at the AAPT meeting.  Excellent recommendation Frank.

If you have some favorite TED Talks, please share the link or the name of the speaker.

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I’ve been a member of American Association of Physics Teachers for about 6 years now.  If you teach physics, please join!  The journals and posters alone are worth the tax deductable annual dues.  I attended my first AAPT meeting a couple of weeks back.  I learned one or two great new things, met some super people, but I was also a bit disappointed.

Let’s get the negative stuff out of the way.

  • I’m used to NSTA, so maybe my reference is unfair.  AAPT was small, really small for a national conference.  I felt like everybody knew each other because it was the same people every year.  You could get through the entire exhibit areas in about an hour.
  • It also felt like the conference was aimed at college educators.  I know the organizers claim it’s not, but I’m giving my opinion here based on attending one day of a much longer conference.
  • I had hoped that the talk on video in the classroom would give lots of useful tips; how to integrate video, success at flipping the classroom, etc.  Most of the discussion was why video lectures won’t replace colleges.

Now the positives:

  • The first timer special and lunch was a great idea.  Lunch and the company was terrific, I’m glad I went.  The first timer $75 one-day special is a great way to try it out.
  • I got to meet some great people, some new, some who I had previously met online (Kathy, Frank).  Everybody was warm and there to interact and learn from each other.
  • I met local AAPT members who are trying to suck me in to local activities.  I am interest, but they always do them on a Friday night and Saturday.  I may submit, I do need local physics buddies but I love my weekends.
  • Andy Rundquist demonstrated a great use of Jing.  He has his students take a picture of their homework, then narrate the work on video.  The video is their homework submission.  Jing limits them to 5 minutes and when they talk, you can immediately tell if they know what they are talking about.  Andy has them do this for every homework, I’m going to use it sparingly.  Super idea.
  • There is free software out there called Tracker that does video analysis.  One cool use was to take a moving object, like a person jumping into the water, identify several points (hands, feet, head) through each frame, and let the software determine the center of gravity and plot  the motion.  Did I mention free?
  • I really like the sessions where there is a new presenter every 10 minutes.  Lots of great stuff, and if it isn’t, it’s only 10 minutes until the next one.

AAPT was worth my time, I wish I had done the entire week.  It was close enough to home that I was able to take public transportation.  Here’s the problem: if you can get your school to pay for you to travel to one national conference, which do you choose – AAPT or NSTA?

For me, it would be an easy choice.  NSTA has so much more to offer, so many more strands, talks, exhibitors, and people to interact with.  I would love to do both, I don’t see how.  I will get involved locally, AAPT is too good of an organization to ignore, they are worthy of our support.

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This is not a new topic for me, it’s been a burr in my saddle for some time now.  All of the introductory physics textbooks address significant figures in much the same way.  The problem is – nobody in the “real world” uses sig figs.  At the same time, introductory physics isn’t the time to introduce complex error analysis models.

I’m having this discussion with Andy Rundquist of Hamline University.  I asked Andy how they handled this at the college level.  He told me they don’t teach significant figures and pointed me to a very lengthy article discussing why significant figures are all wrong.  The article suggests the use of Monte Carlo analysis its place.  That may make sense on a lab, but not on classwork and homework problems.  The uncertainty article did have a suggestion; use six significant figures for calculations and round the final answer to three sig figs.  The article does a good job explaining the reasoning, and I’m fine with it.  The three extra “guard digits” preserve the accuracy, and the rounding makes the answer more reasonable.

The next step is trying to explain uncertainty and significance of our data.  I came up with an activity I think will work:

  • I will project an archery target on the board.
  • Students will move back about 20 feet and shoot a round of Nerf darts at the target.  They will be far enough back that most of them will shoot a 6, or 7 and not a 9 or 10, at least at first.  Each student will take a turn.
  • We will plot the overall results.  We should get something resembling a normal distribution curve, but I won’t tell them that.
  • I will ask the kids to average the data and come up with a value of x.x +/- y.y and start a discussion on whether or not that represents the data.
  • We will then put a ring or other object on an electronic scale and write the mass with the error in the same way.
  • After some discussion, I will bring up slides of normal, rectangular, triangular, and maybe exponential distribution curves.  I want them to discuss the fit of the models to the data.
  • My goal is that they understand that error is probability.
  • About a week later we will drop rulers and calculate individual reaction times.  This would be a good time to bring back the distribution graphs and perhaps even input our data into a statistical analysis program to find the best fit.

I think this will work and go over well.  I’d love some feedback.  It’s a first pass, what did I miss?

What’s New in 2013/2014?

Every year brings a change, this one is no exception.

I will be picking up the sophomore honors Algebra II class to keep them separate from the juniors. This should help accelerate them and put them on a stronger track towards Calculus. Looks like there will be only one section each of Physics and Calculus, but still two of Robotics & Engineering.

Hot topics this year are going to be the Common-Core Standards, Standards-Based Grading (SBG), improving AP Calculus scores, and somehow adding Python, maybe as a club.

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