You’re not blind, I can’t find the about page on the curent layout either. I’ll probably switch to a different design when I get time.

Doug – Maybe I’ve become blind, but I couldn’t find the “about” page on your blog.

My first engineering-based programming I did was to reconstruct a model that took input from the user (temperature etc.), looked up materials parameters from a database (an Excel worksheet in my case), and spit out predicted values for mechanical behavior. I wrote the program in the old XLM language to automate Solver, because we had a value the model output and we needed the corresponding input. Manually it took two days to produce a dozen output values, and the program did it in a couple minutes. So it was a big deal. Up until I wrote the program, I had to submit my conditions to the engineers in another division and wait for them to process the values for me.

My colleague at the division noticed I’d stopped asking them for calculations and wondered how I got mine. I sheepishly admitted it was “only” an Excel solution. I was surprised to learn that they used Excel all the time for engineering work, because I’d envisioned large mainframes (Crays, really) to do the work. They liked my system and implemented it themselves. My first VBA project was to upgrade my XLM materials properties program.

I think your model is an excellent introduction to the sorts of things you can do with spreadsheets in science education. Also I totally agree with your “keep it simple” approach, whilst not forgetting the basics of good design; i.e separating data, analysis, and output.

I think the concept of not plotting #N/A might be somewhat easier for an inexperienced Excel user than the concept of a dynamic range name based on worksheet ranges. A Stephen Bullen-type ChtFrmla defined name is conceptually much more difficult to understand, technically more difficult to construct, and much harder to debug and maintain than a worksheet-based name.

The model as I’ve fashioned it would be more robust, if someone decided to insert a copy of the model worksheet into the same workbook. If the dynamic names were defined on a workbook level, the copied chart would refer to the name defined on the original sheet, not on the copied sheet. If the dynamic names were defined on a worksheet level, the chart on the copied sheet would contain hard-coded values.