Floral litmus solutions

In 2018 I ran the floral litmus solutions laboratory as a demonstration. I remembered that this felt unsatisfying - there is a magic in holding the test tube and watching the colors changes in front of your own eyes. This summer I brought along eye droppers and some smaller test tubes. I then modified the laboratory from the usual structure. The usual structure has been to have the students bring flowers to use, test to see if the flowers work, and then identify unknowns using a working litmus solution. 

Mary with a test tube

I found an old, battered periodic table on top of a cabinet.


The chart allowed me to being the day with an introduction to the periodic table of elements.


Including a crash and dash through electron orbitals through to hydrogen ions and hydroxide ions.


The modification was that I brought in Philippine ground orchid and red hibiscus rosa-sinensis. I boiled water and prepared the litmus solution at the start of the laboratory. The diagram above details the color changes for an acid and a base: this was given up front and moved lime fruit from being a known acid to an unknown substance. I didn't use baking soda because I knew that baking soda does not always react in a color changing way with the hibiscus solution. 


The pipes were so little used that they ran dirty at first. Most of the dirt seemed to be from the pipe, but some of the water color was due to heavy rain on campus. The water would go off at the start of the laboratory, complicating the rinsing of test tubes. I also had a shortage of eyedroppers, which led to some cross-contamination issues early in the laboratory.

Renee-Ann-Seshrue

The students adjusted to the make shift nature of the laboratory and it was much more fun than watching me run this as a demonstration. Lacking eye droppers some substances such as the vinegar were poured into test tube. The paper cups are beakers: the lab has dozens of erlenmeyer flasks and no beakers. Not single one. The paper cups proved worthy and capable.

Sue Malia Crystal

Mikey detects an acid

Elise with the ammonia source from Ace Hardware

All of the substances were purchased by me on island at either Ace Hardware or Ace Office.

Sue Malia Crystal found that the bleach went from green to yellow

Pine Sol and an ammonia based cleaning compound

Jeffan watches as Mikey adds ammonia to the orchid litmus solution


The ammonia was added directly due to the shortage of eye droppers.

Renee-Ann-Seshrue and CharlynRose take notes


With no running water, rinsing was via water from a clear plastic cup filled from the water dispenser on the porch. The students proved very resourceful in getting the laboratory done.

Renee, CharlynRose, Judah, Elise, Mary


A small beaker was used to bring over the eye droppers and small test tubes - I was unable to order beakers and eye droppers online. There were set available, but none would ship to the FSM. Those were the only items I brought over with me. 



This was an active laboratory and all of the students were actively engaged and exploring.

Judah shows Sina the change to an acid

Everyone was involved

CharlynRose, Sue Malia Crystal, Judah, Sina

This version of laboratory 13 was surprisingly successful and may be a useful model going forward for future iterations of the laboratory.

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