January 22, 2011


Its not a new idea, but one I stumbled onto in some reading, that is telling the kids what they should know when they're done with an assignment. Thus the WYSBATDOKWYAD. In my physics class I have moved to a once a week homework with any suggested reading and other reminders listed on top of a print out. As an added bonus the paper has enough space for the students to complete the 3 or 4 problems from the textbook. 

Sometime in the middle of the first semester I started adding the WYSBATDOKWYAD.  The long acronym was mostly a joke, but it worked. The students got a laugh out of it and now remember what it means, if not word for word at least they've got the gist. So what does it mean? 

What You Should Be Able To Do Or Know When You Are Done.

I offered up extra credit if a student could improve on the acronym. So far I've only had a few weak attempts but nothing good yet...

January 19, 2011

More cars

This week in physics I wanted to introduce the idea of impulse as a stepping stone into momentum. I wanted to make a connection between work and impulse and the idea of force over distance and force over time. So out came the ramps and the cars again.

I had them do the following (I gave them some hints not shown):
  1. Create a mathematical expression that relates the the amount of time a force is applied to an object of mass and the velocity of that object. 
  2. Using the ramps and toy cars from before break. Collect 4-5 data points,the data should agree with your answer to #1.  If they don't agree figure out why and adjust.
  3. Put your group's result on the board. 
No fancy equipment needed.
The results weren't quite so magical as before, but they figured out an expression for impulse (but didn't know its name) and gathered data to back up their pencil and paper work. What more can you ask for?

You can almost smell the learning.
In retrospect some of the hints I gave could be removed and allow a little more true inquiry.

The complete document can be found as a google doc.

January 11, 2011

Playing with cars

A few weeks before winter break I wanted to introduce the idea of energy. I usually do this with some boring chalk and talk about how we can use energy to solve more complex problems in a much easier way...

While that works, I'm not sure I get much more buy-in than just filling the chalk board with definitions and equations. Okay maybe that's not quite true, but it feels that way.

This time I decided I wanted to do a little exploration get the kids to figure out something on their own about energy. So as a class we took a short field trip to the maintenance building and got some old gutters and long planks of wood. I let kids (in groups of 3-4) pick their own toy car. I managed to pick up two 5-packs of hotwheels for $10 at Target. I also picked up some $1 slinkies that have yet to find a use...
Finally, I posed 3 questions to each group, the first two just being scaffolding for the last question, and then just got out of the way.
  1. Given initial conditions of your choice, what is the speed of the car at the bottom of the ramp (or just off the ramp)?
  2. What do you have to do to double the speed of the car at the bottom of the ramp? Triple?
  3. What would you have to do so that the car had a final speed of 100 m/s? A theoretical question. 

I was trying to get them to model the idea of velocity squared being proportional to the height above the ground. Thus the length of the ramp and angle are secondary to height. And poof, with a little teacher voodoo the kids would have discovered gravitational potential energy... Well, it was so much better. 

They grabbed stopwatches and meter sticks and went to town. The kids got stuck on number two. One section nailed it during the first period. The other had 3 groups and all 3 got different results. I fought that teacher response of "well the answer really is..."  and said almost nothing. We decided to take one more class period to build a longer (6 meter) gutter ramp, some of the problems were  in measuring the time (we don't have any photogates). The kids spent 45 minutes experimenting and writing down numbers until the whole group saw the pattern! It was hands down the best class period of my career. 

In the end both class periods saw that the height was the determining factor, this required some guiding questions (Jedi mind tricks), and saw that there was more to figuring out the speed of a car than using kinematics and FBD's... There might be something far easier to use.

The handout I gave me students can found as a google doc.

January 07, 2011

What Santa brought me.

Santa brought a new toy for me this Christmas, one I didn't think I had much of a chance to get. I made my case as to why I should get one. But I thought my plea might have been ignored. Its not something that I really needed. Though I have used it a lot (I'm using it now). My friends and students are envious though I'm not sure they'd all make use of it...

What is it you might ask? A new bike? A new pair of skis? Nope. Just good old nerd candy. A new laptop. A free laptop from Google, a Cr-48 to be exact... And yes I said free.

For those who haven't heard Google has been working on an operating system based on their browser Chrome. Thus the name Cr-48. There's not much to it, which seems to be the point. Google was also very clear that the product was not going to be perfect, but that it was giving them out as a trial...  You can find all kinds of nerdy tech details on the interwebs. You can even still apply to get one for free, I'd guess teacher folk have a darn good chance at getting one.

When I heard about the new computer my internal geek wanted one. I realized it could be a pretty nice 1:1 laptop solution for schools. The computer would likely be cheap, they are not for sale yet or maybe not ever, its a lightweight processor, no hard drive, no CD or DVD, but it does have wireless and 3G. The fact that they are cloud based means if a student breaks one they simply have to pick up another and log-in again to have their files back. No more long wait times for the server to push the files down... I had this problem at my first school. The quick start up time matched with the 8-9 hour battery (no typo there) means it could work great for students going from one class to another all day long.

There is no desktop, no real way to download programs or games and thus no way to get a virus or download something that will ruin the performance of the computer as so many of my former students did. All the programs you can run are online apps from the Chrome App Store that work in a browser tab. I already use Google Docs and Sites for most of my school work. I realized a few months back that virtually all my time in front of a computer was doing work in a browser. I do my grades in a browser, I create class materials in a browser and I have become addicted to Google Reader after Dan Meyer mentioned it in a post. It seems like the Cr-48 was a near perfect fit.

The jury is still out. But if Google keeps working on the OS they might have something. For me they need to figure out the printing. I haven't played with their CloudPrint but I don't think its going to work for me, based on what I've read. My other major concern is the lack of support for Vernier probes. I need Vernier probes. I'm sure Vernier is capable of making a cloud based Logger Pro, but its not there yet and that's a problem if the Cr-48 is to be a viable 1:1 solution. There is hope as there is a single USB port...

I also miss my music. There are online solutions, but I haven't gotten that deep into the Kool-Aid just yet.

The Cr-48 is also not capable of running some of the Java based simulations from the PhET folks. As those require a file to be download and installed (I never liked that anyways). It does run the Flash based sims, but maybe a bit sluggishly (I've only tried one so far).

There is great potential...

January 04, 2011

Knocking off the rust with a little geometry

We start back to classes tomorrow. My precalculus course stopped mid-trig identity before the winter break.... We had talked about the reciprocal functions and the inverse cosine and only hinted at more identities.

I am determined to not teach as I was taught and to provide many different ways to see connections. I'm pretty sure that students learn better when I'm not in the way (How can you say that in an interview with out sounding like a lousy teacher?). When they can discover something on their own they remember it, they believe it and maybe they begin to get what I missed in math class. The beauty of patterns and logic!

I had been searching for a way to both review a little and to make all the trig functions real not just some arbitrary function I might write on the board. So I went back to geometry, geometry I never saw in class, so its new and fun for me. I'm not sure my teachers ever saw it either, but its possible that I was face down drooling on my desk in boredom during that part of class...

I had seen the picture below a few times but never stopped to really look at it.

Taken from Wikipedia

I had been thinking about this picture for a while. It seemed to me like a perfect review while learning something new. There might even be a few light bulbs going off "hey my, teacher didn't totally make up those functions!"

I created a quick "worksheet," how I hate that word, that guides them through some review of basic right angle trig, the unit circle and finally gets them to the conclusion that the reciprocal functions have a geometric reality! The intent (and hope) is that I can just get out of the way and let them learn in small collaborative groups. The magic seems to happen when they don't need me, just some questions to guide them...

The worksheet can be found as a google doc. (Still needs a little polish, but writing this was good procrastination.)