It really depends on the age group... I had good fun with first and
second graders, running sharpie marker Thin Layer Chromatography using
coffee-filters and vinegar for the mobile phase. We also ran through a
strawberry DNA extraction... I feel like they would have totally been
up for running agarose gels on some sort of dye, or even sheared
DNA... but I didn't have gel boxes and didn't think to use clear
plastic straws (
http://openwetware.org/wiki/DIYbio:Notebook/Keiki_Gels)
since I thought they might not give a clear enough view... but in
hindsight it probably would have been interesting enough to see the
color move via application of a battery (i.e. 9V). I think I also did
a module on spectroscopy, using diffraction glasses
(
http://www.scitoyscatalog.com/product/RAINBOW.html) and maybe
something similar using polarized glasses.
--
-Nathan