Teaching with a 32SII and a new RPN user (hopefully) Message #1 Posted by Juan J on 18 Oct 2003, 6:10 p.m.
After a busy week, finally I got some time to write about this. It was encouraging for me.
I got a parttime job teaching Physical Chemistry to engineering students at a local college. Last Wednesday, after a laboratory session, we were discussing error analysis and how to fit curves using experiment data. While discussing how to calculate averages and standard deviation using a calculator (it might be the exception rather than the rule, but most college freshmen don’t really read their calculators’ user manuals) when one of the students pulled out an HP 32SII with the stat menu on screen. “How can I do with my calculator?” he asked. I have seen a few 48s and 49s on campus but not in my class and had given up on trying to find one. “Can I use it to show you and everyone?” I asked.
With the 32SII I managed to explain how to calculate averages and other statistics, and how to fit data. Surprisingly, the 32’s menu system proved to be quite good for the job of explaining how to find a function and use it with your data, and when I noticed I was working some examples using it while the class listened and gave their calculators a try. Function names as shown on screen turned out to be useful to explain some concepts. Then I noticed that other manufacturers have mimicked HP’s menu system on their products, and that the 32SII had became a teaching aid. They all had understood what to do with their data and how to do it on their calculators. Finally we discussed about the examinations that rule out most calculators but not the 32. It felt good but it wasn’t the end of it.
The 32SII’s owner was amazed at the power of his machine. After finishing the class, when I gave him his calculator back, he told me that he got it from his father, a retired engineer who received it as a gift (how many of us would like such a gift) with no manual. His father himself had a 41C with some peripherals and had found the 32 of little interest. The kid had managed to learn about RPN and the stack but did not know how to work through complex expressions without using parentheses, among other things. I had to recall the Mach number equation from memory (by that time we were sitting on the grass below a tree) and explained about the fourlevel stack and how to start from the inside out. The benefit of knowing intermediate answers showed by itself. “This expression would need a lot of parentheses if entered in another calculator,” was all he managed to say, adding later “but on the HP it is much easier to solve.”
Then came the next question, “how can I integrate a function?” After making it clear that the 32SII does numerical integration only, we discussed the integral of cos(x) between 1 and 2. The kid understood easily how to enter a function in program memory and then integrate it; later he checked it doing the integral by hand. He didn’t believe his eyes. As most of us did when numerical integration was not standard on calculators.
The next day he approached to me to ask some more things and comment on the 32’s functions. And he had confirmed that his dad’s machine was 41C. “The best scientific calculator family ever made, the 41 series,” I said, mentioning how the 41 had been used on the Space Shuttle when there were no laptops as a backup for the main computer. He found it interesting and said he will get his dad’s 41 to see what it can do. Hopefully he will start to use it. But for the moment he’s been “converted” to RPN. I was happy.
It felt good to see that RPN does not scare users as most marketing experts and similar fauna are inclined to say. And it was encouraging to see the same emotions when discovering it in a college freshman of today that I (and most other users and Forum contributors) felt back when I was his age. I was also amazed that the 32SII could be so fine a teaching aid.
