Posted in Spectroscopy

Excel Roller Coaster – Yes, my hobby is Excel

If you have FUN programming Excel, on a SATURDAY…You MIGHT be a Redneck I mean, you might be a PCHEMIST.


Years ago, I was at home on a Saturday fiddling with a wave function problem in Excel. The plot on the screen was of a couple of cosines, and my 8-year-old son said, “Hey that looks like a roller coaster”.

“It sure does.” I said. “Do you want to make a roller coaster in Excel?”

“Yes!”, he said.

So over the next four hours we had some quality father son time making a roller coaster in Excel. He learned something about cosine functions, and how to put custom backgrounds on a chart. Some of the finer details he did not care much for were anchoring cells, negative error bars, or the mod() function. But he really appreciated the custom look of a white wooden roller coaster and the looping macro that made the coaster run along the track.

You can download the macro-enabled (.xlsm) workbook file from my curiosities page to see how these functions and settings were used. Here is a time-lapse video of my creating the page from scratch. There are some fun tricks so I hope you enjoy it. the background loop is a bit annoying. Sorry.

The coaster uses an infinite loop. To kill it just click Ctrl+Break, and it will stop.

What Excel awesomeness to you have to share? What questions do you have about these functions and settings in this fun application?

Ask in the comments field, and subscribe for more fun in the future (like my Sudoku solving spreadsheet).

Posted in Spectroscopy

Fall Cleaning

Forget Spring. I just purchased a lot of optics, and before I rip them from their protective packaging, I had better review my handling and cleaning techniques.


Fortunately for me, Edmund Optics – the company that sold said optics – is savvy enough to send an email approximately 2 weeks after my purchase with guidelines and reminders about how to care for my optics. Here is their first paragraph followed by a link to the rest of their article. (This is not a sole endorsement of EO, but it is an acknowledgement that this 2-week email practice rocks.)

From EO:

“After purchasing an optical component, exercising proper care can maintain its quality and extend its usable lifetime. Choosing the proper cleaning products and using the proper methods are as important as cleaning the component itself. Improper cleaning practices can damage polished surfaces or specialized coatings that have been used on optics such as lenses, mirrors, filters, or gratings, degrading the performance in almost any application. Also, be aware of your clothing and your environment while cleaning optics; shirts with zippers and buttons can scratch your optics, likewise dirty or dusty environments are not well suited for optical applications.”

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Posted in Education, Physical Chemistry, Science Education, Spectroscopy

What is pchem?

Pchem is short for Physical Chemistry. It is hated by all. It is SO bad (the audience asks, “How bad is it?”), that it has it’s own bumper sticker!
Why is pchem so mistreated?
Like a scientific tax accountant, a P-chemist worries about the energetic balance sheet, the gains and losses of energy, the ratio of usable to unusable energy. We pull the thread through all states of matter – liquid, solid, gas, plasma, elastic, plastic, glass, etc.
My favorite subsection of pchem is symmetry and spectroscopy. Spectroscopy is the study of light interacting with matter. And symmetry is used to decipher these interactions. There is no better example of the mathematical beauty of our universe than the unexpected explanatory power of group theory as it applies to absorption and emission of light.
Fireworks, hair dye, crayons, ink, glow sticks, lightning bugs, and all the rest can be understood through pchem – specifically my field of spectroscopy.
There is much more to pchem. If you have made it this far, then you are truly curious. Therefore, I give you the table of contents to a typical pchem textbook. (You will have to “Look Inside” at the Amazon site to view the TOC.)
And, I ask you to share and subscribe to this blog. Comment below with suggestions for posts.
Posted in D L Williams, Education, NXT Robotics

Radiation-Sensing NXT Robot

I built this NXT robot and equipped it with a dream-gear wireless game controller from and a radiation sensor from This video shows it detecting the radiation coming from an old piece of Fiestaware that used uranium as a pigment. This was prepared for the Austin Science Festival 2010, but I also use it to teach object-oriented programming to my spring physical chemistry class at Sam Houston State University.

YouTube Video

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