I did a fun little science experiment with Timmy the other day (I ran across it on another scrapbooker's blog!). Anyway, basically you put about a 1/2 inch of milk in a shallow dish, then drop a couple of drops each of 3 or 4 colours of food colouring into opposite ends of the dish, so that the colours are as far apart as possible. Next, drop a few drops of liquid dishwashing soap into the centre. The colours come alive, and continuously swirl all over the whole dish making a beautiful kaleidoscope effect for about 10 minutes. It's lovely to watch and provokes lots of "ooohs" and "aaahs". Best of all clean up is a snap, and everything is already in the house!