Junior Lab Brainstorming Exercise: Good science

Last year (August 2010) and this year (August 2011), I have led a brainstorming exercise in Junior Lab lecture. I believe Katie Richardson (aka Karma) may have had the idea for this exercise when she was TA last year. The exercise has two main goals:

• Learn something about what makes "good" science
• Get used to talking and contributing to class discussions

As you can see from the links to the brainstorming pages (above), these goals are clearly stated to the students, and they seem to embrace them.  The students quickly formed groups and there was a lot of discussion.  The students texted or emailed their brainstorming results to me, and I collected the data on the page.  Then there was about 10-15 minutes for students to volunteer to nominate items as most important.  The students also gave pitches in support of their favorite items.  Following this, there were two rounds of voting, with students voting for 0, 1, or 2 items each time.  In both years, "reproducibility" won the contest, something which makes me very optimistic about these early-career scientists!  Of course not all of them will continue on in science, but I would say an understanding of good science will be important for all of them, no matter what their career.

Here are the items that made the final round of voting for 2010 and 2011.  The first number is the votes from first round, the second is the second round:

• 2010
• Reproducibility 11, 15
• Objective / aware of biases -- so the work is actually useful 7, 9
• Creativity -- ask creative questions that are relevant and answer them in creative ways 6, 10
• 2011
• Verification by peers 4, 6
• Reproducibility (detailed procedures) 12, 15
• Objectivity, unbiased 5, 4

Week 4 Lecture, Law of Large Numbers, Intro to Central Limit Theorem and Related Terminology

Yesterday was the 4th week of Junior Lab, and the third lecture (no class Labor Day week).  We started discussing some of the fundamentals that underlie a lot of data analysis.  To do so, we started with a group exercise that involved flipping coins and recording the number of heads and tails.  One of the main goals of the group exercise was to get students involved and contributing to the discussion.  In my opinion, that goal was successful. Out of 16 students, I can recall at least six students who were actively contributing to the discussion for the whole hour. 

The other goal was to use the coin flip as a launching point to discuss probability distributions, probability functions, parent distributions, the law of large numbers, central limit theorem(s), independent measurements, random error, systematic error, etc.  I think this goal was achieved as well.  Below are two photos of the chalkboard, following our 30 or 40 minute discussion. 

Almost all of the words / equations on the left chalkboard were contributed by students.  To spur discussion, I collected the results of their coin flip trials, and then asked an open-ended question "what can we say about these data?  What should we do with them?"  Mean and standard deviation were suggested by Alex.  I used this to define Xi, Xbar as we will talk about them during this semester.  One group of students recorded ten heads in a row.  I pointed out that set of Xi and asked, "how come you were reluctant to report this?  Who cares that it was 10 heads in a row?"  This got students to mention things like "unlikely" and "probability" and even mentioning binomial distributions.  One student, I think Kirstin, described in words how the probability function for 10 coin flips would look, which led to the drawing in the right photo above.

My memory is hazy at this point, but we started talking about how to test whether the coins were actually fair.  I asked what the measurements would look like if I asked them to measure the widths of the coins.  Students' intuition, not surprisingly was that most sets of observations we thought of would have a bell-shaped distribution.  I asked if anyone knew why this was, and there were many good intuitive explanations.  Alex, brought up the Central Limit Theorem, which delighted me.  At that point, I wrote down in words / symbols a version of the central limit theorem, and we ended class pretty much on that note.  I then showed them a Google spreadsheets example of the Central Limit Theorem in action for uniformly distributed random numbers from 0-1, see below.

Central Limit Theorem Spreadsheet


All in all, I think the class was successful, but I don't have any real measurement of that.  Many students were very engaged, and almost all of the terminology and principles were contributed by students as opposed to me.  I told them my goal for them is not to memorize any formulas or theorems, but rather to gain an understanding of them and an intuition so that when they encounter data analysis tasks in the future, they will know that there is an underlying theoretical framework that they can go read about and relearn.  I feel like the kind of discussions we had yesterday will likely achieve that goal for most of them.

Next week, we'll continue along these lines.  We'll look at their coin-flip data and approach the question, "how do we test whether the coins are fair coins?"  Or, we may do another group exercise that generates new measurements that we can look at.  Or, a third option is to use data that students generate during the lab sessions.  My gut is telling me to continue trying to do small group exercises at the beginning of class, since it does seem to be boosting student engagement quite a bit relative to prior years.  Thanks to TA Katie Richardson for suggesting I do the group exercises!

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First lecture in conceptual physics course, Wason selection task was effective

Yesterday I presented my first lecture of the semester in Physics 102, "Introduction to Physics." The alternate course title I like best would be "Conceptual Physics," and others are "Physics without Math," "Physics for Poets," "Why the Sky is Blue," etc. You can find my syllabus on Scribd. Here are the goals stated in the syllabus:

The primary goal of the course is to help students develop a better understanding of a variety of physics concepts that they experience or hear about in their every day lives. We will strive for true understanding of the concept versus tiresome memorization of facts and trivia. This may lead to a heightened enjoyment of everyday physics wonders (such as rainbows, sunsets, waves, phases of the moon), improved ability to understand technological issues (such as energy shortages and sources, nuclear power and radiation, cell phone communication), and a deeper understanding of future scientific material including biology, chemistry, geology, medicine, and possibly a subsequent more advanced physics course!

I like these goals, but they are not measurable, really. I did not take the time this semester to implement pre-testing and post-testing assessment as I had hoped. Perhaps partially the reason I didn't is I'm still quite annoyed that this is the last time I'm going to teach this class for a number of years. Our department has a custom of switching courses every 3 years, and also I was told that I need to show diversity in teaching in order to get tenure. I strongly disagree with both of these notions, but well, you know...

In any case, the goals are to have fun learning some physics concepts and to come away from the course with a positive impression of physics and science and an ability to enjoy learning about them. I don't have rigorous data, just informal student feedback (thank you emails, which I absolutely love to receive) and the scantron feedback forms. But this anectdotal evidence indicates that our goals were achieved the first two years. Plus, I have really enjoyed it and felt good that many students learned a lot and enjoyed the course. The only negative is that it takes a lot of time, especially the first semester I taught the course, where I developed about 28 powrepoint lectures from scratch, 75 minutes each--that utterly kicked my ass. I would like to put all of my powerpoint lectures on Scribd, in case they could ever be useful to someone else. The only thing keeping me from doing this is that I know I've missed attribution of some of the pictures I've "borrowed" for my lectures. Plus, I definitely don't have copyright on many of the non-CC licensed images I've used. Any comments on how to deal with this? I have in mind that I could try to correct this as I present the lectures this term, but realistically, that's not going to happen.

I did post my yesterday's introduction slides on Slideshare. I think the only stuff I use is from wikipedia and I attribute it. Overall, the lecture went well and I had a great time. Once again, the students are fantastic and I am sure I will enjoy getting to know them and seeing them succeed. I have some comments on a couple specific things from yesterday.

Wason Selection Task

One thing I do during my first lecture is take pictures of all of the students while they are doing group discussion. This accomplishes a number of things. First, it gets them acquainted to talking with their neighbors, which we do several times / lecture. Second, it allows me to practice learning names over the next couple weeks. I have each group write down their names along with physical description and then I go around the room taking photos of the group and telling them their group number. It will take me a couple hours to put the names with the faces in powerpoint, and then a couple more hours of studying. Combined with interacting with the students, I've been able to learn quite a few of their names. I did pretty well with 120 students last year, but this semester I have 154 students registered, so I'm nervous whether I'll be able to do this or not. I think it's important, though, and the ability to talk to people by name adds a lot of value for students. Incidentally, I'm helped by the fact that students tend to sit in the same areas every day, so I'm basically making a seating chart without imposing one. This is a technique I learned from TA training, and it works really well. Thank you to whoever did TA training at Cornell Physics in 1996!

OK, so in order to carry out this exercise on the first day, I need an entertaining puzzle for the students to debate with each other. The first two years, I tried using the Monty Hall paradox. That worked pretty well, but this year I switched to the Wason selection task. I was REALLY happy with the way this turned out. First, I had them use their iClickers with the number / color version of the selection task. Since most of them did not yet have iClickers, I also had them shout out their answers (surprisingly, it's pretty easy to poll 150 students this way, and the shouts matched the iClicker graphs). Most people got the puzzle wrong (which is what always happens), and after debating, a consensus developed on the "wrong" answer (to flip over all the cards). The reason I liked this puzzle so much is because when I showed the same logic puzzle with the beer / under 21 version, then entire class immediately picked the correct answer. I could then show the two questions next to each other and blab some stuff about how learning is contextual. I think it does demonstrate that, but the important thing is that they probably had fun while I took photos and probably remembered the exercise in a positive light and some probably even tried it out on their friends after class. I'll definitely use this for my next large class.

Wireless in the classroom

Someone on friendfeed recently posted an article talking about either the perils or opportunities of wireless in the classroom. It turns out my classroom has wireless for the first time, so I brought this issue up with the students. I basically told them I was worried about the possible distraction, but that the worry was far outweighed by the possible benefits it could have. I was telling them I didn't really know how we'd leverage it, but that I encouraged people to use it. While saying this, I saw a Mac laptop in front of someone, so I said, "Like you, Mac Guy (I don't know their names yet)...you're probably already checking out our facebook page, aren't you?" He said, "Yeah! actually I am...I'm looking at photos of you." (At this point I realized that there must be a bunch of embarrassing photos of me on facebook.) I said, "like what?" and he said, "Some marching band photos..." I made a perfect dramatic pause and then addressed the class, "Well...you already knew I was a dork." This drew much laughter, which made me happy. OK, that little anecdote was unnecessary, but it was funny if you were there. This wireless experiment will be interesting throughout the semester. The one thing I have in mind is that we look at a lot of applets during lecture, and I'm hoping the students will be trying them out themselves while I'm showing it on the projector. I can see that this could turn into mayhem, but I also feel that the level of learning will be much higher if they can play with the applet themselves. We'll see!

Tomorrow we'll do the first real physics lecture, where we'll talk about the structure of matter, focused around Brownian motion. The two demos will be a demo that shakes ball bearings on an overhead projector (to give an idea of molecules in a gas) and a demo where we look at laser speckle off wet and dry paint. This latter demo is really cool and easy to do, and I find it a fascinating demonstration of Brownian motion without need for a microscope. I learned it from Dan Ralph during his graduate solid state physics course at Cornell back in 1997-ish. You'll need to see it with your own eyes (maybe I can take a video of it?), but the laser speckle pattern on dry paint does not change if you keep your head still. On wet paint, the pattern shimmers, due to the microscopic latex particles undergoing Brownian motion. So, basically you can see evidence of Brownian motion with a cheap laser and paint. Laser speckle is a great demo, because you can see it from any distance away, and it's fun to look at whether or not it's shimmering.

01 Course Intro, Administrative, Etc After Class

View more presentations from Steve Koch. (tags: introduction physics)