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I agree with you. Would you teach kids today to use a slide rule? It seems hard to justify for the benefit in intuition about exponents/logarithms.

• WalterBright 4y ago
  I was taught to use a slide rule in 5 minutes. It's just one moving part, and you read the numbers off the scale. Yes, I'd teach kids to use a slide rule. It's not necessary for them to become expert at it, just get comfortable with it. Why learn exponents? People will never learn compound interest without getting comfortable with exponents. Not learning compound interest will forever financially cripple them. Hell yes, it's worth while. My accounting class was taught by a former used car salesman. He'd tell me stories about how poor people made very bad choices in financing, and when he'd explain how compound interest worked, they'd assume he was trying to cheat them. For me personally, knowing math and trig, etc., has provided me a lifetime of payback. Very, very worth it, in dollars and cents.
  • mlyle 4y ago
    I'm not saying that math and trig are not valuable.... I'm merely questioning whether a slide rule has the best payoff of those few minutes vs. say, watching Powers of Ten by C & R Eames. I don't think you cultivate the kind of intuitive understanding of exponents and logarithms you're describing with a few minutes of casual practice with a slide rule.
    • WalterBright 4y ago
      It worked for me. I never spent much of any time with a slide rule, but played with it enough to see that yes, adding logarithms to multiply worked like magic. (This was in high school.) My first semester at Caltech had slide rules in the bookstore for $125 (mebbe close to a grand today). By the end of the semester, they were $5, and disappeared by the 2nd. I've never seen a tech revolution hit so hard and so fast. The trouble with calculators is they impart no feel whatsoever for the math behind it. You get a string of 10 digits that is "The Answer". People get led astray by that all the time, including professionals. It's amazing how these people defend obviously wrong results because the calculator gives "The Answer".
      • mlyle 4y ago
        Yah, we don't use calculators much, either. Graphing calculators used to be nice to occasionally use to help build an intuitive sense of the "shape" of a function. Now I often use Desmos for the same thing. I was a long term sub for 8th grade science a couple years ago. It was fun to use Desmos for linear regression as they collected data points-- to see how each point changed the line of best fit before these students had learned L.R. in any rigorous way themselves. It made students excited to get each next point in our experiment and make predictions about whether they believe the line, etc. (And whether we can safely extrapolate past the data we have...) In the competitive math series I coach, one of the 3 rounds allows calculator usage. Usually using the calculator is a trap instead of doing something clever, but sometimes the calculator is the best way. I think it's kind of neat that they built it this way, because it requires building the intuition to realize whether you're really facing a problem that is purely calculation.
        • WalterBright 4y ago
          What you're doing sounds very good.