A simple science project can be made with a cup of water and several M&Ms or Skittles. Students can drop the candies into the water letter-side-up and observe the reaction between the water and the edible-ink letters on the candies. After about a minute, an "M" or an "S" letter will peel off and float toward the surface of the water in the cup. Have student discuss water as a substance and how it has the potential to react with other substances.
It takes more than a minute for the "m" and "s" to come off the candy but it definitely did happen. Here are some pics of the project, I only uploaded some that were distorted with the funky lens but you get the idea.