Tuesday, March 29, 2011

On Overhead Projectors and Transparencies

As much as everyone hates PowerPoint, maybe we need to step back and realize that it might have some value. Consider these two examples.

I ran across this statement the other day
"He [Kurt Symanzik] used hand-written slides for an overhead projector (which were the industry standard at the time for technical presentations). However, he obviously wrote out his slides with lined paper underneath as a guide, using every line. So he ended up with over 25 lines of equations and text per page. His handwriting was typical German: undecipherable, at least to Americans, looking like endless up-down-up-down-up-down. The clincher, though, was when an equation on one page referred to an equation on another. He'd slap the second slide on top of the first, off-set the two by half a line and point to both."
Source

And then there was the prof that I had for my partial differential equations class in grad school at Illinois. He would carry his own overhead projector into the class despite their already being one there. His projector was special - it had two handcranked rollers, one at the top of the projection glass and one at the bottom, with a continuous roll of transparency film . (You can see where this is going, huh?). He'd start out writing by hand the lecture, which wasn't a problem. The issues arose when he started referring back to earlier parts of the lecture, cranking the roll back and forth as needed, sometimes really getting wound up and going back to something that was written in a previous lecture. After a few minutes of this (questions only made the whole matter worse), everyone was hopelessly lost. Needless to say, I did not do well in the class. (A few well-placed drops of cyanoacrylate adhesive could have solved the problem, but there would have been no way that I would have not been ROFL clearly implicating myself.)

Sure, PowerPoint can be abused and badly mishandled, but whatever I've seen is but a misdemeanor compared to these overhead transparency capital offenses. By the way, check out the PowerPoint suggestions over at ChemBark. As he says, they'll make you a lot less annoying.

3 comments:

Frank Van Haste said...

Hi, John...

You've gone and opened up the memory bank. I have done my share of presentations using overheads (why did the IBM'ers call 'em foils?) and I came away with the conviction that the medium is innocent. The right (wrong?) presenter can make a hash out of any medium.

BTW, I still lament the passing of x-y pen plotters. The overhead slides they produced, if competently done, were heartbreakingly beautiful.

I miss impact printers, too.

Regards,

Frank

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Paul said...

I've seen those projectors with rolls attached, but never in use.

I saw the great Leslie Orgel give a talk at Harvard (~2005 or so) with transparencies. After that, nothing but computerized presentations.

The last time I saw a research chalk talk (dry erase pen, actually) was in ~2001 by Jay Siegel during a seminar at NYU. It was a great talk and quite refreshing.