Since Peeps are on sale for pennies right now, we went and bought lots of them just so we could do this experiment over and over again. It is so fun to watch them grow and grow and grow! The science of it is that Peeps are basically water and sugar. When the water heats up, it begins to melt the sugar and the combination creates a gas inside of the contained microwave causing them to grow. If you have left over Peeps you should give this a try. These were the best pictures I could get of our experiment. We tried different times, different colors and different amounts of the Peeps.