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Comment by wirrbel | Hacker News Reader

I studied physics and this at a time when faculty gradually changed from blackboard-based lectures to powerpoint. The blackboard-based lectures were far superior to any other way of lecturing (in my view).

Main benefit was in the speed of presentation. Writing on a blackboard takes some time, the lecturer is slow enough in presenting that you can really follow along, while not "standing still". What a contrast to powerpoint presentations where the lecturer paused for a minute or two to let students read the equations. Either time was not enough, or you'd start to get bored.

Until I graduated at the end of my 5 year program, I tutored freshmen students. Towards the end of my time at uni, they almost exclusively had lectures with powerpoints. I sat in one of the into lectures and what had been a good introductory course to classical mechanics had turned into a mind-numbing powerpoint karaoke show.

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I find another benefit of blackboard presentation is the order of information. The lecturer can build something up rather than simply showing the finished article and saying voila.

Working a project on a blackboard also encourages people to get the order right. It's surprisingly common to see Powerpoints which skip or reorder steps completely because the slide creator shuffled things around or worked backwards from the answer.

I'm sure most people have seen professors skip numerous steps on blackboards, too, but in my experience there's at least a heightened awareness of what it looks like to actually work through the problem.

What's best about black/whiteboards for me is precisely the nonlinearity. Numerous times I've seen professors realize near step 10 of the proof that something they said in step 3 isn't quite right; then a sidebar is opened and arrows start to be drawn to piece the puzzle together.

The point of going to classes versus studying alone at home is that you get to watch mathematicians doing mathematics. It's apprenticeship learning, the same as carpentry. Watching the professor reason and make mistakes and second-guess himself is invaluable. The typed class notes where everything is neat and theorems are numbered gives the impression of an immaculate birth that the student can't fathom arriving at. The best maths classes are the ones that teach you how to be a mathematician.

This is a much better expression of what's great about chalkboards than just the order of steps, thank you. It's not so much seeing a problem worked out in sequence as seeing it worked out for real. Even if the professor is working from lecture notes with all the steps, writing them out live engages with the content in a way that pressing "next bullet" doesn't. And as you said, what's missing is the messiness - catching mistakes in the notes, making mistakes on the board and finding them, puzzling over what belonged at a missing step.

Everyone jokes about the frustration of copying a full blackboard worth of notes and then having the professor go "wait no, that wasn't right" (myself included) but it's a valuable experience. That moment of "hm, hold on a second" is where the math is happening, and a chalkboard helps professors and students notice that. (And of course, when something "isn't quite right" on the Powerpoint, it's a tremendous pain to fix...)

It's not that they CAN, its that they HAVE to.

A great teacher will be a great teacher with whatever you give them. But anyone not 100% tuned to that part of their teaching greatly benefits from some of the constraints that chalk gives them.

I'm a K-12 admin and once we had a HS teacher who was brilliant but her classes were often too difficult to follow for the kids. We just told her she couldn't use the powerpoint slides anymore. Yes, there was a huge discussion of timing and pedagogy and all of that, but ultimately, placing that constraint on her naturally put her at a much more equal footing to the students she was trying to teach.

When you try to force could behavior by handciapping people, you also get utter failures like teachers with bad (or too-slow) handwriting who cannot succeed at conveying information via the arbitrary restriction.

But slides have one big advantage: they can be posted online for later review so students can follow the lecture instead of taking notes.

I think it's even better if the slides are posted prior to the lecture so that interested students can make their notes annotations on the slides - this allows them to fill in trouble spots while not having to copy down all the material (I find it distracting to try to rush to copy everything down, personally).

I had a math instructor record his blackboard lectures and posted them online later that day. Just another consideration.

If the professor just recorded the lecture, I'd imagine most students would never go to class again.

As someone in college who has had their classes recorded and posted online, I still go to class because its dedicated time to my brain. There is nothing else I should be doing other than being in class.

The people who don't show up would have not showed up class recorded or not. It is very useful though when you have a morning class miss or be dead tired and not pay attention to re-watch the lecture to get a better understanding.

It seems like whatever recording either I or the professor make are actually useful to me later on. It's always the classes I don't record are the ones I always need.

If no one goes to the physical classroom why not sell the same recorded lecture to a thousand people online instead of the 100 that fit into a classroom?

I had a world history/geography/current events kind of class in college that had an in-person lecture and was also livestreamed and recorded. Lecture hall fit about 1800 people but he also had an unlimited class size "online" section you could sign up for if you didn't get in-person section during early course request. You never actually had to go to class. The professor had to get his own system for taking quizes and handing in assignments since the online learning management system the school used would choke with that many students at once trying to submit things.

Content aside, it was a very interestingly run course. Assignments were at your own pace, you had a large list of the kinds of projects you could turn in for credit. There were quizzes, exams, essay topics, interview topics, and an option for independent projects to get credit. Each kind of project had it's own maximum point value it would be graded out of and the final grade was totally based on how many points your actually earned, not out of how many. Even if you did a shit job on every assignment, as long as you did enough of them, you could get an A. It was a nice way to boost the GPA from just sheer effort rather than actual achievement.

Or better yet, give it away for free!

https://www.edx.org/school/mitx

All the math tutorials I watch are on youtube at a virtual blackboard! They draw them out just as parent was describing.

So can copies of handwritten lecture notes.

That can be done with power point slides as well technically but seldom is - both in use and being used when it is suitable.

> Main benefit was in the speed of presentation. Writing on a blackboard takes some time, the lecturer is slow enough in presenting that you can really follow along, while not "standing still".

While I love chalk, and miss it since my current university uses whiteboards (actually stupid @#@#* WallTalkers, despite our pleas), it's hardly the case that the two options are 'chalk' or 'Powerpoint'. Also, Powerpoint slides can be delivered at a reasonable pace—I've seen many professors fruitfully use slides with blanks, distributed to the students in advance, on which students can take notes—and chalk-and-talk lectures are scarcely universal models of pacing—one 'remedy' often pursued by lecturers who want to go faster than they can write is just not to write anything.

In EE blackboards were mostly replaced shortly before / while I was there a few years ago. Whiteboards are _vastly_ inferior for two reasons in my view:

1. Colours are harder to distinguish, or to see at all. Chalk is easy, even a brand new pen is difficult from more than a few rows back, possibly made worse by my colour blindness;

2. You can't go over an existing pen line. You can _sort of_ make it thicker (but typically remove part of it at the same time) but you can't draw a square and then go over one edge in red, for example.

In one of the class I had, which used Powerpoint, I had a pdf version of the slides, on which I added notes, all on the corresponding slides.

I once had a professor that would write on the blackboard with his right hand and erase with his left simultaneously. Quite a struggle to keep up with equations on those days he chose to fly through lectures like that!

I feel like some things work on powerpoints and other onthe blackboard, for example maths work a lot better on blackboard. Some of our best lecturers had a powerpoint but they first showed the equations on them after they had showed them on the blackboard, which I found pretty good.

When did this happen? I got my PhD in physics in 2008 and other than the introductory undergrad classes, all other classes (that I knew of, at least) were still taught using chalkboard/whiteboards.

And I agree with a sibling comment on this thread. The speed of information is ideal with live ‘writing/derivation’, as you can follow along at the teacher’s own pace and write each step yourself.

I used to do his for my own section classes I taught as a TA. I’d come in with a small post-it size note of starting points, and just work brought problems without referencing anything else. Kept it down to Earth, and I think (or hope) showed the students there’s nothing insanely hard here, just lots of small bite-sized steps.

Personally I find it is the responsiveness that is the real benefit with a good professor - they can respond and go off into areas a power point slide would not be prepared for. Ultimately the worth of a tool is in how it is used.

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