I love this experiment! I learned it in an Early Childhood inservice. You place different colors of m&m's in a clear cup with enough water to cover them, and, after some time the students can see what happens with the different colors.
Hot or cold? A simple science experiment for kids: We measured the temperature at the beginning of the day, and at the end of the day.Students found out at the end of the day that the temperatures were the same in all cups.