heart shaped tray or cups
In a bowl mix water with the food coloring you choose, then slowly add in baking soda till you have a mixture you can pick up and pack into a mold. Top with glitter and let it dry. I suggest you do not put it in the freezer, I did and the fizzing reaction took awhile to happen and was not as big as it would have been if not frozen. When me and my kids did this experiment we just talked about Valentines day and what they thought about it. I would have explained this reaction between the baking soda and vinegar but this is a experiment we do in all different ways and they are well aware of the reaction between the two.