Balloon Blow Up Lab

I use this lab as an introduction to the basic chemistry portion of the living environment curriculum. It is a pretty elementary experiment that many children have done in one form or another (Volcanoes!) but they may not have measured the results and considered the chemical reactions taking place or used a graph to estimate the equivalence point (the mass of baking soda at which the number (moles) of both reactants would be equal and hence used up). I calculated their molar masses and figured out that with 50 mL vinegar, that point should be somewhere between 5 and 10 grams of baking soda, unless I made an error somewhere. Please let me know if you find a mistake.

I also added the bromthymol blue piece to the lab, which I haven't done before. It’s optional if you don’t have any. It is added in the initial test (1 gram) only, just because I like to introduce indicators as early as possible to use as an example later on when I get the inevitable, “how do scientists know…?” It illustrates one example of the ingenuity that goes into seeing things that can’t be seen.

I've done this lab for a long time, back to my middle school days, but in writing it up this summer I took some of the introductory text from K-12 Outreach: NSF & Science and Technology Center for Environmentally Responsible Solvents and Processes (CERSP)

Here's my version. I'm getting a little fatigued from all the summer work. I am busily working on flashcards, curriculum mapping, etc., and writing these labs is mentally draining - this may be the last one for a while.

Chemical Reactions: Balloon Blow Up