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"La mathematica l'alfabeto nel quale DIO ha scritto l'universo"
"Mathematics is the alphabet with which God has written the universe."
 --  Galileo Galilei --
Donald in Mathmagic Land.  I saw this for the first time in 6th or 7th grade.  It enthralled me.  Math was everywhere.  It took my high school math teachers to temporarily ruin it all for me.  I was ready and eager, but their presentation was of this hugely complex and un-understandable topic that only intellectual giants, such as themselves, could comprehend.  It wasn't until I was in college that I again found enthusiasm for this topic.  The professors loved what they were teaching - it was a key to solving puzzles.  Better yet - it wasn't hard.  It was just sets of logic rules that NEVER changed.  My wife found a copy of this at Costco years ago and bought it.  I watch it at least once a year just to recapture the magic.  While it is currently out of print, it can be found on Amazon as a used item.

Mathcad - What is a great program for doing math, has recently become prohibitively expensive.  A stand-alone copy of version 12 will set you back $1200. An upgrade from a recent version will cost $300.  My wife originally bought me a copy (version 3) for $129 back in 1991.  I kept my personal copy up-to-date through version 9 (MathCad 2000), but have stopped the bleeding.  I do maintain my work copy current and will be upgrading to version 12 in the near future.

Now that all the negative has been said - let's concentrate on the positive.  I've used Mathematica, a variety flavors of Fortran, and Excel spreadsheets to conduct engineering calculations in support of work.  Nothing compares to the ease of use and flexibility of MathCad.  Calculations are self-documenting and easy to follow.  If the math is correct and the inputs check - then the results are right.  Easy to use, easy to check.  There are limitations in its ability to handle multi-dimensional arrays and differential equations.  When I hit these types of problems, I either look for another way to approach the issue or turn to other tools.

I've included some example worksheets on the website for working with water properties and heat exchangers.  There are now better add-ons available through MathSoft's partners for handling the steam tables, but I think these are still insightful.

HP-41.  Wahoo!  A calculator that thinks like we do.  If you haven't ever tried a RPN calculator - find one, do some math, and be amazed.  No parentheses, no entering the equations left to right.  The work is done the way you work with equations.  Order is maintained. (Okay, my wife and kids hate it - but I cannot even use a algebraic calculator anymore).  I got my first HP-41 when I was in college as a replacement for an old TI-30.  It was an eye-opening experience.  I was hooked.  It was my first real introduction into programming and I bit hard.  If there was ever an activity I might repeat more than once - it was programmed in my HP-41.

What is really cool is that while the HP-41 is no longer manufactured, emulators are available for most computing platforms at   This site not only has the emulators, but HP has released most, if not all, the application ROMs.  I have this on all my PCs and my PocketPC.  I've also included some of my own applications on this website.

Slide Rules  In my sophomore year in college I was taking a Mechanics and Material's class.  On the first couple of quizzes I totally screwed up my answers.  My approach was spot-on, but my answers were way out.  The instructor correctly surmised  I was just punching the numbers into my calculator and trusting the results.  I had no feel for what was going on in the equations.  He brought out a slide rule from his desk, presented it and an instruction book, and told me that was all I would be allowed to use the rest of the semester in his class.  Initially it seemed mean and unfair, but as my skills developed I found myself developing an understanding of the equations that had eluded me.  I still will periodically work through a problem with a slide rule just to make sure I understand what is going on. 

I had written up some information on slide rules, but then found a really great site devoted to the topic.  Check out "Eric's Slide Rule Site"

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This site was last updated 09/20/04