When M&M’s are placed in water, the outer shell, which is made of sugar, dissolves. The sugar moves from a place of high concentration (the M&M) to a place of low concentration (the water away from the M&M). When the sugar shell dissolves and moves outward, it takes the layer of food dye with it. When more than one M&M is placed into a petri dish the colors do not mix because the concentration of sugar at the interface is approximately the same. Also, around the bottom of the M&M water appears cloudy because the partially dissolved sugar is more dense than the water, so it sinks.
– petri dish
– white paper
1. Place the petri dish on white paper
2. Add a small amount of water to the petri dish
3. Place M&Ms at the edges of the petri dish, equally spaced around the dish
This demo would work great on an overhead. Different patterns can be made by placing the M&Ms in different places around the dish and by using different colors.
Safety goggles should be worn at all times.
Meerman, Ruben. “Cool Colour Experiment.” Posted 20 June 2007. Accessed 17 June 2010. http://www.abc.net.au/science/surfingscientist/pdf/lesson_plan15.pdf