David
 
Your request reminded me of an excercise we did in early high school (a long
time ago) I don't remember all the details, but it had a satisfactory
impression, perhaps you can reinvent it.
 
I think it used dialysis tubing, dissolved starch (or sucrose) and a (starch?)
indicator (iodine?). I remember a "sausage" of the dialysis tubing, filled with
a test liquid, immersed in a clear jar of another liquid, perhaps with the
indicator. Some of the test liquids (starch?) sat inert in the liquid, while
others (with invertase?) showed a slow cascade of colour, as the (sugar?)
diffused through (into the indicator?). I remember I got a particularly good
result by adding honey.
Good luck
 
Kerry Clark, Apiculture Specialist
B.C. Ministry of Agriculture
1201 103 Ave
Dawson Creek B.C.
        V1G 4J2  CANADA          Tel (604) 784-2225     fax (604) 784-2299
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