Reference:"Spreadsheet Computer Models in Instrumental
Analysis", Symposium on Integrating Computers Into The
Undergraduate Curriculum, American Chemical Society Fall
Meeting, Washington, DC, 1992
First posted online in 1994. Last updated in July, 2020
Color Temperature of a Blackbody Source
Animated Diffraction Grating
Photomultiplier Light Measurement System
Comparison of Analytical Calibration Methods
Wavelength modulation system
Dual Wavelength Spectrophotometer
Instrumental Deviations from Beer's Law
Calibration Curve Fitting Methods in Absorption Spectroscopy
Signal-to-Noise Ratio of Absorption Spectrophotometry
Effect of Slit Width on Signal-to-Noise Ratio in Absorption Spectroscopy
Scanning Fluorescence Spectrometer
Fluorescence Spectroscopy Signal-to-Noise Ratio
Signal and Photon SNR of Atomic Emission Spectrometer
Effect of Slit Width on Emission Spectroscopy SNR
Line Wing Overlap
Calcium Ion Selective Electrode model
Resolution of Capillary
Triprotic Titration Data Analysis
Monoprotic Titration Curve model
This is a collection of free, downloadable, interactive computer
models of common analytical instruments and techniques. Most have
a point-and-click interface; you click buttons and drag sliders to
control variables and the model responds dynamically, often much
faster than real time. Note that these are not really
simulations of particular commercial instruments and were
not intended to train instrument operators. They are rather
interactively manipulable mathematical models that are essentially
sets of linked equations that describe various parts of or aspects
of each system. The advantage of linking these equations in
spreadsheet is that it gives the students and instructor an
opportunity to explore how these textbook relationships interact
with one another. My models give you the ability to change many of
the chemical and instrumental variables that effect the outcome,
including not only the variables that are conventionally
adjustable in the laboratory (such as the wavelength of a
spectrometer or the concentration of a chemical solution), but
also the instrumental design variables that are determined by the
instrument manufacturer and can not normally be adjusted by the
experimenter (such as the ruling density of a grating or the focal
length of a spectrometer).
Most of the spreadsheets produce graphs and charts that
illustrate the internal operation of, or mimic the output
generated by, these systems. Because they are just spreadsheets,
it's easy for instructors and students to inspect the equations
that drive these models. Unlike closed proprietary programs, the
mathematical basis of these models is not hidden but
rather easily accessible and can be viewed, modified, corrected,
or extended by any instructor who is familiar with the basics of
modern spreadsheet construction.
I originally designed these models for courses I used to teach
during the 1990's at the University of Maryland at College Park: Instrumental
Analysis (an upper-division undergraduate laboratory course)
and Spectrochemical Methods (a graduate lecture course).
The spreadsheets were based on the level of treatment in the
textbooks for those courses and were designed to be used by
individual students either as homework assignments, for in-class
use in a computer lab environment, in the laboratory for the
analysis of student-generated data, or as a supplement to
laboratory experiments, to allow investigations into the
fundamentals of system behavior for which time is not available in
the laboratory. The spreadsheets can also be used by the
instructor in lecture-demonstration environments.
Student-assignment handouts and suggested experiments are included
for most of them.
The mathematical basis for each model is described in PDF files,
including all cell definitions and equations that relate the
variables. The equations themselves are usually taken directly
from the typical textbook treatment for each topic, sometimes with
additions from other sources or with the addition of small amounts
of random variability to make the behavior closer to real
Instructors are able to, and are invited to, modify these
spreadsheets in any way for their students. See the unsolicited user comments below
from actual users of these spreadsheets.
Calc is the Open Document spreadsheet format, part of the OpenOffice Suite, which students and faculty can download and use without cost, from OpenOffice.org for Windows, Macintosh, and Linux. Calc is basically the same as Excel. To run these Calc spreadsheets, you have to first download the OpenOffice installer (download from openoffice.org), then install it (by double-clicking on the installer file that you just downloaded), and then download my spreadsheets from this site. Once OpenOffice is installed, you can run my spreadsheets just by double-clicking on them. The OpenOffice suits also includes a full-featured word processor, a presentation program, and other components. There is no need for students to buy the expensive Microsoft Office suite; the latest version of OpenOffice is always available for free download. Note: Downloading the individual spreadsheet .ods files with some versions of Interent Explorer will change the file types from ".ods" to ".zip"; you will have to edit the file names and change the extensions back to ".ods" for them to work properly. This problem does not occur in Firefox or in Chrome.
The Calc versions of these models will also run
Calc, for example running
on a Raspberry Pi 3.
These models were originally developed in the early 90's in WingZ (.WKZ) format, the first object-oriented spreadsheet with a built-in scripting language called HyperScript., but that program is now obsolete. This is still a useful format, because the HyperScript language has some has some unique capabilities that are useful in this sort of simulation and because the WingZ player program has a very modest memory footprint and runs very quickly even on older, smaller, or slower 32-bit computers (but not unfortunately on 64-bit Windows). I am gradually re-writing these models in the industry-standard, non-proprietary Open Document format (using OpenOffice Calc) and in Excel, but until that work is complete, some of them will be available only in the original WingZ format. To open the WKZ files you'll need the "player" application that is included in the following file archives for both PCs and Mac:
If you have suggestions for other models like these that you would like to see developed, please email me at firstname.lastname@example.org
"I was able to get everything working nicely and can promise you they will be helpful with my students."
"Today I had the first simulation experiment and the students were excited...."
"The [simulated] lab was much more interesting than the
lecture, this is for sure!...I had very
good feedback from students..."
"...thank you so much for your website!!! "
found [your worksheets] of great
use whilst working on my current project."
Nice work … and lots of it. Your stuff is wonderful!"
"I found your website very informative."
"What I like about your grating demo is that it clearly
shows how increased dispersion causes the different wavelengths
to have to travel different distances to the sensor...."
"Let me congratulate you on a fine web page! I'm a technical support engineer for Wingz ... and I rarely run across such sophisticated use of our products."