Floral litmus solutions

April 08, 2022

Monday I began with an introduction to the periodic table. Some students have had chemistry in high school, others have not. For all of the students the periodic table was a long time ago and long forgotten.

I began as I usually do, covering hydrogen and the isotopes of hydrogen which relate to the development of the "hydrogen" bomb,the Castle Bravo test, and the legacy of radioactive waste in the Marshall islands.

I moved on to helium, lithium, and berylium.

And, yes, there are many misrepresentations in these diagrams from a quantum mechanically correct wave-particle model.

Wednesday I reviewed the basic coverage of Monday (erased from the board in the image below).

I moved from orbital diagram to electron dot diagrams. I wrapped up with an introduction to the idea of acids and bases. I opted to run with a naked hydrogen proton as explaining the H₃O hydronium ion overly complicates matters for non-majors.

Renay tests her floral solution for reaction to baking soda

On Thursday the class engaged in a floral litmus solution laboratory. Every term I forget something. This term I remembered to print out the labels, a common oversight. I brought scotch tape, but the tape was not necessary. I did use a new brand of baking soda, one in a plastic bag that I thought might be more reactive, but it wasn't. I need to consider using something that is perhaps more strongly basic. This term I forgot the remote control. I should also spend some time in perhaps the hardware store looking for new unknowns to add to the lab.

Jessie May loads her test tubes with her floral litmus solution

As I often do, I introduced the laboratory by noting the presence of glassware in the PICS chemistry classroom, but a lack of chemicals. I explain that with just glassware, laboratories can be done.

Darla Rose tests her floral litmus solution

Cyron and Richard have just finished boiling their flower

Cyron is testing Sphagneticola trilobata

Sphagneticola trilobata did change hue angle for the lime fruit, the known acid, but did not react with the baking soda. I did not test the flower against ammonia. Baking soda seems unreliable as a base in this laboratory. Hibiscus rosa-sinensis can detect bases but does not always react to the baking soda with a change in hue angle. That was the case this term as well. In the 11:00 class everyone would use the Spathoglottis plicata I had brought in.

Richard records results

Adelina tests an unknown substance

Jessie May

Heavy rain fell during the morning session

The Sansui was running a playlist.

I want the physical science laboratory to have a different, hopefully friendlier feel, so I run a automatically generated playlist in the background.

Board setup

Unknowns included vinegar, diluted bleach, and ammonia.

The bleach must be diluted or the bleach quickly bleaches out the color change.

Isopropyl alcohol and the sidewalk chalk both register as neutral. The shampoo is apparently not pH balanced as it is consistently strongly acidic. The laundry detergent is basic.

The hand soap is basic, the anti-bacterial hand soap was neutral however. And while many cleaning compounds are basic, this Lysol is strongly acidic. Citric acid is a primary ingredient.