Modern Physics screencasting update again

This week we're having our first exam. The oral part was yesterday and they did very well. The format is the following:

• All 5 (yes, I know, only 5) students take the oral together
• Each student gets 10 minutes to complete a problem on the board.
  • The problems are chosen from homework problems and derivations in the book
  • There are five possible problems so all are done by someone
  • If they get stuck it costs them 5 points (out of a total of 100) to get unstuck by me
• They then answer one follow up question from each of their classmates.
  • In the end they all ask 4 questions worth 5 points each (if I don't like the question, they don't get the points

Each of the problems that they had to do could be found on Blackboard as a screencast. Four were homework problems that were found under the solutions folder and one was the Bohr derivation that I did as a supplemental material screencast when I covered Bohr.

I gather they studied by watching the screencasts because they did very well. Tomorrow is the written test so we'll see how well they're learning using this approach.

Modern Physics screencasting update

This is an update about my use of screencasting in Modern Physics.

The class has now started and things are going well so far. I'm using Jing exclusively for the screencasts but instead of hosting them on screencast.com I'm just posting them to BlackBoard. So far Blackboard isn't complaining about the files sizes (between 0.5 and 5 MB) and hopefully it won't complain about the cumulative total (about 15 MB so far). I like using Bb for several reasons. First I'm worried about running out of room on screencast.com (2GB total) but also because I think I'll reserve that space for screencasts for a more general audience (like my screencast that show how to use my grade page or my summary page that all students use). Second I like how you can control when students have access to the screencasts. Of course I could host the screencasts on a Hamline server and just put in an external link in Bb (that I could control access to) but the students might get lucky and guess the url of other screencasts that I'm trying to control. Third I really like how you can track the viewing by student to know if they're actually making use of the screencasts.

Here's what I'm doing for a given class period. I type up a general outline of the material, careful to skip any details that warrant a separate screencast. I then make any additional screencasts for any details I feel might be confusing from the book. Finally I make a screencast for every homework problem (and make sure they don't have access until after the quiz on the homework given in class).

In class we do a quiz on a randomly selected homework problem (using a four-sided die so that students don't waste time trying to guess which problem I'm going to pick) and then I answer any questions they have about the reading that they've posted on my summaries page (link above). If there's time I answer any further questions and give them hints on how to do the homework problems.

The response from the students so far has been cautious optimism. On the first day when I introduced the basic concept one student said that it seemed like I was putting the responsibility on them to learn. I took that as a positive comment. On the second day all but one had used all the screencasts (the one who hadn't thought he didn't have Bb access) and said they "liked it". I'll continue to get feedback from them and adjust as we move forward.

A feature I'd like to start using is to have students use Jing to post questions to me. They could either use Bb or they could use my grade page to post those. Imagine being able to listen to a student showing where they were having problems in, say, Mathematica rather than getting their notebook and trying to discern their syntax!

Quantum mechanics without imaginary numbers

I've been thinking about how the Schroedinger equation intimidates students because it is inherently complex:

(note the red i). This has led me in the past to say things like "quantum mechanics is weird because apparently the universe is both real and imaginary" and "we can only see the real parts". Now that last quote especially is suspect since what we can "see" is really the magnitude squared of the wavefunction:

which corresponds to the probability density of finding something in a particular location. But I'm coming around to a position where even the first quote above is suspect. It seems to me that you can rewrite the equation as two coupled equations:


Note how the 1's and 2's switch places. What I've done here is renamed the real part of as and the imaginary part of as . Only here I'm just numbering them and not really giving any preference to either. These two equations are totally equivalent to the original equation and what it says about the universe is that for every object you need to keep track of two things. In the end to make predictions about the object you'll need but note that I don't need imaginary numbers at all!

I think interpreting those two equation is of interest as well. Essentially the spatial curvature of one produces temporal changes in the other and vice versa. That's actually pretty cool as you could stare at a snapshot of both the two and predict what's going to happen in the next moment of time.

screencasting software

Well, the news came out last week about Google Video being shut down. I was not exactly happy given my plans for screencasting this coming spring semester. So I've spent the week trying to find some other alternatives. Here I'll put in a few of my findings. TeachTube Teachertube has similar lack of limits to file size and total number of uploads as Google Video. It's optimal resolution is half of Google's (320x240 vs 640x480) but Google actually reduces your videos to 320x240 after some processing anyways. You can mark you files as private and embed videos just like Google too. They have a semi-malfunctioning feature where you can upload support files to go along with the video. Overall it seems like a decent alternative to Google. Btw, the malfunctioning part is that when you click on the support files you're taken to a page with EVERY support file listed. WinFF I don't like the default file size that camstudio produces so I'm starting to use winFF to reduce it by roughly a factor of 2 by converting to .mp4 format from the avi format. The quality once it's on Google seems about the same. Jing Just today I started using Jing on my mac (it works on macs and windoze). It's pretty slick as the screen capture that it does seems to have very small file sizes (3.5MB/minute for full screen) AND they host your screencast for you at screencast.com for free! You get 2GB of space and 2GB/month bandwidth which is pretty good. What I really like about it is how easy it makes everything. You can keep it running in the background and when you make a video the controls are obvious and then when you're done it immediately puts it on screencast.com for you. All with one piece of software! There's also no delay between uploading and being able to view it. Plus they don't do any post-processing to reduce the quality. Of course the biggest downside is the 5 minute limit on videos but I'm willing to work with that! Elluminate Live This is software that Hamline has paid an academic license for. It's actually very slick. I used it yesterday during an interview I was a part of and I was very impressed. It's designed for online courses and I'm planning to use it immediately for my ongoing online course. I really like how you can grant microphone privileges to anyone logged in and how students can "raise their hand". It keeps track of who raised their hand first. Very cool. It also lets you share other windows on your screen so it would work very much like a screen cast. Well, we'll see how it goes this week . . .

Almost two weeks without tv

I don't really miss it. This past weekend there were a couple of times where just vegging in front of it sounded good but I knew there wasn't really anything on. On weeknights I've been busy cleaning the kitchen, brewing my iced tea for the next day, checking the discussion boards for my online class (online quantum mechanics, sounds fun, huh?), reading books, and posting to my blog. The boys are usually in bed by 8 and I go to bed around 10:30 so it's just 2.5 hours to fill. Dexter season 2 came in the mail recently and I am pining for it. I can't decide if that's allowed or not. I suppose I know deep down that it's not but it does sound like fun to watch. At least I wouldn't be watching commercials and I could pause it any time to deal with anything that comes up (I've been getting the evil eye from my wife for not responding to the kids when the tv's on). There's really no single show that I miss. I know Law and Order will always be there for me and things like Hulu.com seem to have the oldies but goodies so I don't feel like I have to watch something the night it premiers. Of course this is all during my j-term at Hamline when all I'm teaching is my online course. Once the spring semester starts I'll probably just use the time to get work done (like grading, the bane of my existence). We'll see.

Cereal with less than 10 g of sugar

In our continuing efforts to keep the kids healthy, I've decided to enforce a hard threshold of less than 10 g of sugar per serving in their cereal. I came to that number mostly arbitrarily but it's worked out pretty well. Almost every cereal you would think of as a sugar cereal has 10 or more and almost every healthy cereal has less than 10. We get plenty of stares in the cereal aisle at the grocery store. The boys pore over the ingredients list of all the cereals hoping to find one under the threshold. The first time was the most fun when they were happy to find some surprises:

• Honeycomb is over the limit but Chocolate Honeycomb isn't
• Fruity Pebbles is over the limit but Bam Bam Fruity Pebbles isn't
• Life is ok
• Fruit Loops is way over
• Any raisin cereal is WAY over (that's weird)

Buddy (9) argues quite often about cereals that have exactly 10:

Why can't we get ________?! It's 10, that's just one more than 9 and you let us get 9! (not 9 factorial, of course) It's just a tiny bit more!

I respond that there has to be a limit somewhere and that I'm not really all that happy about 9. We've had that conversation a number of times.

Update (12/13/2009): General Mills apparently reads my blog They're going to reduce the sugar in many cereals down to 9 g just so I'll buy more.  Cool!

My new diet

I'm trying to be a little more healthy this year so I'm trying to follow my new diet more closely. It's actually very simple: if it's homemade, you can eat all you want. I figure that all the weird preservatives and other added chemicals (like the ominous MSG, for example) in packaged foods can't be good for you so even if the homemade food is not that great for you, if you fill up on it you'll hopefully be less likely to eat the pre-packaged stuff. I'm also trying to kick the fake sugar habit by drinking iced tea when I can (with just lemon added). I've been thinking about the diet for a while (probably since back when I was on the South Beach diet) but the momentum really got going when the big boys and I watched a cooking show on PBS that showed how to make homemade macaroni and cheese. The boys actually said it looked good! I jumped all over that and we went to get the ingredients right away. I don't think we made it that night but it was pretty soon afterwards. They did like it, though not as much as they thought, and I pigged out (it's homemade, after all). That night I didn't snack on anything! My goals for dieting are three-fold: 1. fit into my clothes (not that big of a deal since I can always just buy bigger ones); 2. Be able to run up and down the basketball court or play at least 5 games of SocCourt without needed to fall over and hyperventilate; 3. actually I was going to say stay below some embarrassing weight but I find that if (2) is fine, I don't actually care. I'll admit that tonight we had Mickey D's for dinner but I'm still trying my best to eat healthy things when I can.