Spoon baking soda into each cookie cutter on the baking sheet.
Sprinkle glitter on top of the baking soda-filled cookie cutters.
Place a small container of vinegar (colored with a couple of drops of food coloring) and an eyedropper nearby.
Help your child fill the eyedropper with vinegar and squeeze it onto the baking soda-filled cookie cutters.
Encourage your child by saying something like, "Look! What's happening? What do you hear? What do you see?" Explain that baking soda and vinegar together make a chemical reaction that you can see, hear, feel, and even smell (vinegar).
Fizzy Hearts - Valentine's Day Science or Kids https://b-inspiredmama.com/fizzy-hearts-science-for-kids/