Floral pigments as litmus solutions

Laboratory thirteen in physical science had the students collect flowers from around campus, produce floral solutions by boiling in water, and then test to see which floral solutions changed color for both a known acid and a known base. Teaching in the tropics makes this laboratory possible in both November and April, or even in July.
Achimy pours hot water on  flower petals.
Sussy prepares petals for boiling.
Carlyne sorts out test tubes.
Adam with a floral litmus solution that turns magenta when an acid is added.
Rihter and Carlyne work with the known acid (lime fruit) and the known base (baking soda).
Elizabeth adds lime juice to a test tube held by Jason. Monaliza looks on.
Carlyne and Iumileen testing one of their floral solutions.
Loioshi and Evelyn work with the unknowns, attempting to determine whether they are acidic, basic, or neutral.
MaryHellan with a floral litmus solution.
Merlisa and Kioleen clean their flower petals for boiling.
Brian and Ceasar testing one their floral solutions for a color change as a result of lime juice being added.
A table full of flowers.
Iumileen with a color changing floral litmus solution.
Joshua working with a flower fluid that turns bright red in the presence of an acid.
 
Lupe with a floral solution that turns green in the presence of a base, magenta in the presence of an acid. 

This laboratory remains a favorite of the students. This term six of thirty-two picked laboratory thirteen as their favorite laboratory. Only one student chose thirteen as their least favorite laboratory. In the tropics we are blessed with many different flowers and colored leaves to try. For those in temperate climates, Fred Senese covers some of the options available. Senese also notes that onions and vanilla are olfactory pH indicators.

Comments

Post a Comment

Popular posts from this blog

Plotting polar coordinates in Desmos and a vector addition demonstrator

Image
In an earlier post I noted that Desmos did not directly plot polar coordinates. Not only was I incorrect, but Desmos responded to my blog to correct me! Although I had at some point seen that one could define a function f(x)=3x+5 and then have Desmos calculate f(6), I had not absorbed how this might be used to plot polar coordinates. The above works beautifully . Realizing that I could effectively program Desmos, I applied this thinking to demonstrating how to add two vectors when given the magnitudes m and the direction angles theta. The graph calculates the i and j components for the two vectors and then adds the vectors, graphically displaying the result while also providing information on the magnitude and direction of the vector sum. m1 and theta1 are the magnitude and direction angle for one of the two vectors, m2 and theta2 are the magnitude and direction for the other vector. All four are dynamically interactive and can be changed. The diagram purports to illustra...
Read more

Setting up a boxplot chart in Google Sheets with multiple boxplots on a single chart

Image
The  Google Statistics  add-on for Google Sheets can display multiple boxplots in a single chart. The key is the layout of the data. One column should be the variable by which the data is to be grouped, the other column should be the data to be box plotted. Set up the Statistics add-on with the data to be plotted as the variable, and the grouping column as the "by" variable. In this image I had deselected all but the boxplot option, the result was the appearance of the Moment, Standard errors, and Confidence intervals options. The default is apparently a 95% confidence interval for the mean. The result is multiple boxplots on a single chart with a common scale. The new tab that is created also quotes 95% confidence intervals for the mean. Note that as of 2018 the Google Statistics add-on cannot be found by search in the add-ons. In addition, as of May 2018 the add-on no longer verifies, possibly due to the add-on not having been updated since August 2017. One may ha...
Read more

Traditional food dishes of Micronesia

Image
Clara, Jennette, and Joanie presented ground hard taro cooked in an umw, effectively a hot rock oven. Pohnpeian: rotama. Pingelapese: sero. Mwoakillese: rodma. Mortlockese: Amahd. Kosrae: rodoma. After cooking in an umw the rotama is pounded with the petiole of a palm frond. Rotama is made from hard or swamp taro, known as mwahng on Pohnpei, mweian on Pingalap, pula in Mortlockese, and pahsruhk on Kosrae. In traditional times on the outer islands the women had primary responsibility for tending the taro while the men handled fishing and climbing tasks. Joesen and Noeleen presented fermented breadfruit from the outer islands of Yap such as Woleai and Eauripik. The raw ingredients were actually brought in from Yap, Noeleen prepared the maare.  The leaf wrap is ti leaf - Cordyline fruticosa. Pauleen, Barnson, Trisha, Verginia, Con-ray, and Maylanda from Kitti, Pohnpei brought in mahi umw, koahpnoair koakihr, and uht sukusuk. Above is breadfruit umw, mahi umw, o...
Read more