sure!
so I bought a pack of both candies... and then sort of took 2 of each of the basic colours out (you know, red, blue, yellow etc)... try to choose the candies of relatively the same size to be accurate.
then dip them in water just for a few seconds, like really quickly...
then rub the candy on filter paper or coffee filter paper... ask the science faculty for some if you don't have this.... yeah, so rub the candy so that the wet colour can be transferred onto the paper. then place the paper suspended (vertically) in a glass of water with a pinch of salt, but so that the water doesn't quite touch the bit of colour.
wait a few minutes and then... hopefully....the colour should have travelled up the paper.... give it like 20-30 minutes though....
(the black candies work especially well, as you are able to see the various sub-colours that make it up...)
then compare the colour rising of the MnMs and Skittles candies and see which one travelled more and give possible reasons why etc...
maybe even talk about what colours made up other colours...the black one for example, had bits of red, blue and yellow colour...
this is just off the top of my head...
I actually got the idea off this website:
http://scifun.chem.wisc.edu/homeexpts/candy.htm
its actually really helpful!!
hope this helps!!!
Good luck!!