Yesterday we were at the RAF Cosford Museum to run activities as part of the Chemistry at Work event for schools. We’ve been before and it remains a spectacular venue for outreach.
Again we took our ‘Is Faster Better?’ activity, looking at catalysis through the catalysed decomposition of hydrogen peroxide. We introduced a new catalyst that introduced a degree of unpredictability to the whole experiment.
Keeping the test tubes at arms length!
We adapted this prep to use iron trichloride powder and 0.1M solution. During testing, the tiny quantities of powder and drops of solution created a fairly satisfactory result, compared to solid/aqueous KI and yeast. But ‘in reality’ both were fairly unpredictable. Clearly better catalysts provided your aim was good and the bulk of the stuff got into the peroxide-soap mixture, but if not, quite bizarre and unreliable. The good thing about comparing a microspatula tip of solid with three drops of 0.1 M FeCl3 (or 2M KI) is you can discuss quantity and dissolution as factors. You do have to be adaptable however when one set of reagents does something different every time!
Richard with a school group
The museum is still a wonderful place to do science outreach of any sort, surrounded by the planes, tanks, cars and missiles!