Over at NPR, Adam Frank has an ode to the use of chalk for teaching science, including a bit of warm fuzzy nostalgia:
I have powerful memories of tracking through derivations presented in class when I was a student. When done well, they pinned my attention down. The act of copying what was appearing on the board was a kind of meditation. You had to stay awake and aware, like a man walking across a frozen pond. Let your mind wander for a moment and BAM! You were lost. You couldn’t see how the professor had gotten from one step to the next. But keep your focus and you’d be rewarded with that most precious gift: understanding.
If you could follow what happened on the board, when the last notes of the derivation ended you would be left with the epiphany of knowing, truly knowing, what that mathematical expression for energy generation in a star or the expansion of the universe meant and how you’d gotten there.
On reading that, I was overcome with my own wave of memories. I recall it like yesterday, sitting in the classroom at the back corner of the Thompson Physics Lab at Williams, for my sophomore E&M class. The professor was the most senior of the faculty at that time, and lectured exclusively with chalk. He would start in the upper left corner of the board, and work his way down and across, covering the entire thing with intricate derivations of the important fundamentals of electricity and magnetism, vector calculus, and principles of symmetry and the like.
And he had an incredible ability to make absolutely any letter look like a Q. Or a q. If you didn’t catch the name of the symbols at the exact instant that he wrote them on the board, the equations were a hopeless muddle:
$latex E_{total} = Q\frac{1}{4qq_0}\frac{q_1q_2}{q^q}\hat{q} $
Did I mention that he had a tendency to face the board while he was writing? And mumble a bit at times?
That’s why the class is so firmly fixed in my memory– because I was in constant terror of missing the identity of an illegible symbol. In fact, that’s really the only thing I retained from that course– the memory of fear and confusion. I certainly didn’t keep any of the content.
Snark aside, this is why the annual round of panegyrics for the beauty of chalk-talks and the ugliness of PowerPoint mostly provoke eye-rolling on my part. (And Frank’s piece is more eye-rolly than most…) It’s very popular in faculty circles to wax rhapsodic about the beauty of a good chalkboard lecture, which we really appreciated back when we were walking uphill through the snow to class. There’s an elegance there that kids these days with their PowerPoint slides and their smartphone just can’t grasp. And their music is just noise.
But in reality, PowerPoint is a tool, just like chalk is a tool. You can give a great lecture with PowerPoint slides, just like you can give a great lecture with chalk. And you can give a lecture using chalk that is every bit as terrible as the very worst PowerPoint presentation. They’re both just tools, and you have to know how to use them effectively, and what their strengths and weaknesses are.
If you want to show images, or real data, there’s nothing better than PowerPoint. The actual picture or graph will always be better than a reproduction drawn on a chalkboard, unless you’re one of those trompe l’oeil sidewalk artists that turn up in my Facebook feed all the time. And PowerPoint slides are almost guaranteed to be legible (strategic font choices can make them hard to read), and are easily electronically distributed to the class.
Chalk (or whiteboard markers) allows for a little more context– you can fit more of a derivation on the typical chalkboard than you would be able to on a PowerPoint slide. And writing on a board tends to force a slightly slower pace that can be beneficial– it’s very tempting to blow through PowerPoint slides at a too-fast pace, but harder to do the same when writing by hand, unless you skip steps. On the faculty prep side, it’s somewhat easier to do equation-heavy classes with chalk, because it’s tedious to typeset the equations in PowerPoint. I’m doing my Quantum Optics course this term using the whiteboard for exactly this reason (I post scans of my handwritten notes on the class web site, so students have a second chance to puzzle through my scrawl at their leisure).
But there’s nothing intrinsically better or worse about either method. You can do a great class with either, and you can do a terrible class with either. The only difference is the weight of tradition– because PowerPoint is relatively new, people (especially faculty, but also students) tend to blame it for the failings of a poorly done class. If you teach using PowerPoint, you are virtually guaranteed to get at least one complaint about it (though if you do it well, you’ll also get positive comments), and any flaws in the organization or presentation of the material will be blamed on PowerPoint.
But really, it’s a tool, nothing more. The fault is not in the tool, but the poor craftsman who doesn’t know how to use it properly.
(“Featured image” above from QuickMeme.)
For a class I taught a few years ago (small class, small room) I used a combination of PowerPoint plus whiteboard. I projected right on the whiteboard but could augment the slide by writing on the board, either to the side of the slide, or directly on the projection to illustrate some detail.
I agree with your point that PowerPoint is just a tool, and I’ve seen good and bad lectures whether done with chalk, overheads, or PowerPoint.
Way back when when I took intro physics (one of the courses nearly every science major was required to take) it was in a large lecture hall with multiple chalkboards that could slide over each other. The professor had the practice of coming in before lecture and filling every square inch of available space with lecture notes. Then during the lecture he could just talk while pointing to the blackboard. It was difficult to keep up and students who had the period before hand free got into the habit of coming in before class and filling up their own notebooks while the professor wrote.
In contrast, when I took organic chem, another note-heavy class, the department the entire class notes available (for a nominal purchase to cover the copying) so that students could more easily follow the lecture and annotate their notes while listening to the prof.
Indeed, PowerPoint is a tool, and one of the keys to effective transmission of information is using the right tool for the job. I agree that chalkboard/whiteboard is the way to go for heavy-duty mathematics, and PowerPoint is better for stuff that’s more image heavy (data graphs, diagrammed chemical formulas, etc.) In between are the many lectures that can be equally well delivered in either medium, as well as a few cases where it is desirable to use both.
There is one key difference with PowerPoint: Unlike chalkboard space and viewgraphs, PowerPoint slides are an unlimited resource. You don’t have to plan in advance how you are going to use the available real estate. (Though many of my professors solved this problem in chalk lectures by erasing material from the beginning of the lecture to reuse the space later in the lecture–one more incentive to show up for class on time.) The result is that it’s easier to cram more material than can be readily comprehended into a PowerPoint presentation than into a comparable chalk talk. As you correctly note, this isn’t the only way for a presentation to go wrong, but it is one of the leading causes of bad presentations.
I use Beamer. Say what you will about Power Point, the MS product is really terrible when it comes to reproducing mathematical formulas. Sure you can just cut & paste. But with Beamer, you don’t have to do even that.
I can’t stand slide. It takes me 3-4 times longer to prepare them than to just give the lecture on the blackboard. In addition, if you make a set of slides, you’re going to make those the set of notes as well, which is really an inferior method.
I prefer to use blackboards/whiteboards, and transparencies to give lectures. Afterwards, I can type up a proper set of note, which will then be ready for next year. A good set of notes over many years could probably also form the foundation of a book or chapter of some kind, but a set of slides will only form the foundation of those 6 to a page, bite-size bullet point printouts.
Did I mention it takes me hours to make slides?