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Re: [Phys-l] Significant figures -- again



On 03/13/2012 11:40 AM, Richard Tarara wrote:
Again, as always, the depth and precision of one's teaching
depends heavily on the audience and the course goals. Preparing future
physicists is different than preparing future artists, bankers, and the
like.

I agree with those generalities ... but I don't think they are
on point.

Bankers actually understand the concept of /significance/ ...
they call it "materiality". They know it is different from
precision, and they absolutely do *not* use anything resembling
sig-figs rules for calculating it.

As for artists and poets, do the experiment sometime. I have.
When I ask a practicing artist if they learned about sig figs
in high school, they usually say something like "Yeah, I
remember something about that, but it never made any sense
to me."

To which I reply: "There's a reason why it never made any
sense to you. That's because it doesn't make any sense."

1) As I have said before, if the class is not ready for any real
appreciation of uncertainty, don't teach them sig figs. Just
tell them to round everything off to 3 decimal places (in
scientific notation) and leave it at that. (Worrying about
the uncertainty can come later, if at all.)

Surely there are already not enough hours in your day, and not
enough minutes in each hour of class. Surely the time spent
on sig figs could be better spent on something that actually
makes sense ... something that will not have to be unlearned
later.

2) For that matter, if/when your class *is* ready for a real
appreciation of uncertainty, once again you should not teach
them sig figs. Other methods are easier and in every way
better.