After 24 years, I can honestly recommend the time and effort involved in putting up this colorful holiday classroom decoration — pictured on front cover. The first two years I took the tree apart after the holidays, put away all of the clamps and reassembled the tree the following year. After the third year, I decided to simply store the tree and remake some of the solutions. The choice ended up a relatively expensive one — I had to replace almost my entire supply of clamps. I had used almost all of them on the tree.
This chemis-tree is not just decoration but offers an opportunity to cover some chemistry concepts, particularly solutions. I emphasize that recognizing the color associated with particular ions is a key to identifying some solutions. The colors of the solutions are aqua blue (dilute copper(II) sulfate), deep blue (copper(II) ammonia complex), green (nickel(II) nitrate), yellow (sodium chromate), orange (potassium dichromate), pinks and purples (varying concentrations of potassium permanganate).I don’t currently have a red solution, but I am considering an acid/base indicator, providing another chance to use the chemis-tree to introduce chemistry concepts.
If you look carefully at the tree pictured on the front cover, you can also see a silvered flask and separatory funnel. These are from my first tree, made in class over 24 years ago. The sealed flask and funnel are unchanged from the day I silvered them. The mirror silvering recipe is a very old one dating back to the late 1920s and one of my favorites. The solutions are shelf stable and very small volumes are needed to silver containers. Those interested in this lab activity can contact Jean Hein at Chem 13 News to have a copy emailed to them.
One interesting anecdote about the tree: When my mother-in-law was still alive, she visited my classroom and fell in love with my chemis-tree. I ended up setting it up in her living room window during the Christmas break. She considered the tree a fine work of art. I also have trained my students to politely correct visitors who comment on the Christmas tree, “that it isn’t a Christmas tree it is a chemis-tree”.
