29 October 2018: We wrote up all the details of the experiment of the previous two weeks, exploring the chemical reaction of beautiful, rose-red phenolphthalein dye (not misspelled!  It’s fen-ohl-thay-leen), for which we ranged beyond chemistry to electronics, light transmission, construction, data analysis, experimental design, and more.  We hope you may find this interesting, illuminating, and fun.  Thanks for reading this!

(From the link on the first line, you’ll get a thumbnail of the first page; click on it to read the whole story, as a PDF file – 16 pages, 1.5 MB.)