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In honor of Valentine’s Day, today I’m sharing my love of chemistry on the blog. Chemistry and math were my favorite subjects in High School, and the main reason I loved chemistry so much were the experiments. Chemical reactions are always fascinating to watch and I had so much fun in chemistry lab every week.

Valentine’s Day is a day to celebrate love, so I thought it was a great time to introduce my kids to one of my loves: chemistry. I hope this will start a life-long love affair with the subject for them too!

I am going to introduce my kids to chemistry with the classic chemical reaction of baking soda and vinegar. This is the good ol’ combo that makes lots of foam and bubbles (you probably made volcanoes erupt using these ingredients in elementary school).

We’re going to use the baking soda and vinegar combo in three Valentine’s Day themed experiments: Foaming hidden colors, foaming ice cubes, and foaming “rocks” with hidden prizes.

Let’s talk about the science behind the baking soda and vinegar chemical reaction

Baking soda is the common name for the base sodium bicarbonate (NaHCO3). Vinegar is a mixture of acetic acid and water known as dilute acetic acid (CH3COOH). The baking soda and vinegar reaction is an acid-base reaction. The baking soda (base) wants a proton, and the vinegar (acid) wants to get rid of a proton.

When baking soda and vinegar are mixed together in water they form sodium acetate – a salt (CH3COONa), water (H2O), and carbon dioxide (CO2). This happens quickly and the carbon dioxide is released as a gas, which is what creates the fizz, foam and bubbles that are observed in the experiments.

The chemical reaction is written as:

NaHCO3(s) + CH3COOH(l) -> CH3COONa(aq) + H2O(l) + CO2(g)


Now let’s do some chemistry experiments…but first let’s have a safety talk. The following safety talk is applicable to all three experiments presented below and should be read and understood before attempting any of the experiments.

A chemical reaction occurs in the following experiments which creates CO2 bubbles. There is very small chance that the bubbles can rise out of the dish and if you are watching too closely can splash into your eyes. If this happens, immediately flush the eyes with water until they are no longer irritated.

To prevent this unlikely event from happening, don’t observe the reaction too closely, and/or wear eye protection. We have fun colored small safety glasses that fit my kids’ heads well. They wear them for our experiments and just for fun!

The food coloring is optional. The colors make the experiment more fun for children, but it’s also messier. Food coloring can stain clothing, furniture, and skin.

If you chose to use food coloring, it’s a good idea to protect your work surfaces by covering them with newspapers or paper towels and wear clothes you don’t mind getting stained. It’s always a good idea to read the labels on the food coloring and choose a brand that has ingredients you are comfortable with using in your home.

Finally, I recommend these fun experiments for children aged 18 months+. My 3-1/2 year old son was fully participating and engaged in the experiments. My 15 month old daughter had fun observing the experiments (and we helped her participate whenever possible).

Foaming hidden colors

In this experiment your children will learn about chemical reactions, work on fine motor skills by using the squeeze bottle, and identify colors.

Materials needed:

  • Baking soda
  • Vinegar
  • 3 small clear dishes
  • Food coloring (optional, but recommended)
  • Small squeeze bottle
  • Safety Glasses (optional)


(Tip: Do steps 1-4 without your children present so the colors are a surprise!)

  1. Drop 6 drops of food coloring at the bottom of each clear dish. I hid “Valentine” colors red, purple, and magenta, here’s how: red – 6 drops of red, purple: 3 drops red and 2 drops blue, magenta: 5 drops red and 1 drop blue.
  2. Cover the food coloring in each of the 3 dishes with a thin layer of baking soda (about 1-2 tablespoons per dish).
  3. Place the 3 dishes on a tray (this is to prevent accidental spillage onto your table).
  4. Fill the squeeze bottle with vinegar.
  5. Have your child squeeze the vinegar slowly into each dish one at a time to reveal the hidden color and watch it foam.
  6. Ask your child the identify each color as it is revealed.

Baby sister was able to participate in the experiment with our help (but we couldn’t get her to leave on her safety glasses…)

What happened:

When the vinegar was poured onto the baking soda the chemical reaction immediately began. Carbon dioxide gas was released creating the foam. As the foam created by the chemical reaction dissipated, the hidden color was revealed.

Foaming ice cubes

In this experiment your children will learn about measurement, change of state, and chemical reaction.

Materials needed:

  • Baking soda
  • Water
  • Food coloring (optional, but recommended)
  • Ice cube tray
  • Squeeze bottle
  • Vinegar
  • Small glass bowls and/or tray with high sides
  • Safely glasses (optional)


  1. Mix 1/2 cup baking soda, 1/2 cup water and 10 drops food coloring of your choice.

My son loves to help measure the ingredients
  • Pour mixture into ice cube trays and freeze overnight (or until they’re frozen solid).
    Note: the baking soda will not fully dissolve in the water so you will have to continually stir as you pour into the ice cube tray to ensure each ice cube will have lots of baking soda in it.

  • It just takes a little chemistry experiment to get my son to look at me with that much love! 😉
  • Once completely frozen, remove the ice cubes from the mold.
  • Place the ice cubes in a small bowl filled with vinegar…
    …or on a tray with high edges and use the squeeze bottle to pour vinegar over the ice cubes and watch them foam as they melt.
    We did both methods and both were fun!
  • What happened:

    Your children are learning about measurement, changes of state, and chemical reactions in this experiment. Your child learned about counting and measurement while creating the colored water-baking soda mixture used to form the ice cubes.

    When your child made the mixture and poured it into the ice cube tray it was a liquid, but when you pull the ice cube tray from the freezer the mixture is a solid. The water changed state from liquid to solid in the freezer because the temperature dropped below water’s freezing point. As the room temperature vinegar is poured into the frozen ice cubes, the temperature begins to rise back to room temperature and the ice cubes begin to melt and change state back to liquid.

    As the ice cubes melted the baking soda and vinegar combined in a chemical reaction and carbon dioxide gas was released creating the foam that was observed.

    Foaming “rocks” with hidden prizes

    In this experiment your child will learn about chemical reactions, and get a fun surprise!

    Materials needed:

    • Baking soda
    • Water
    • Food coloring (optional, but recommended)
    • Small toy (such as bouncy ball, penny, etc)
    • Small clear glass bowls
    • Vinegar
    • Safety glasses (optional)


    (Tip: The first time you do this experiment prepare Steps 1-3 without your children so the toy reveal will be a surprise! If they like this experiment, you can do the experiment again and let them help prepare Steps 1-3 so they can practice measuring and have fun molding the “rocks”)

    1. Combine 1 cup baking soda, 1/4 cup water, and 10 drops food coloring of your choice until a thick moldable dough forms. Add more baking soda if it’s too wet or more water if it’s too dry.
    2. Hide toys inside golf ball sized pieces of dough.
      I put the dough in my hand, made a well in the center, added the toy, and then molded the dough around the toy.
    3. Mold the filled dough into round balls (to form the “rock”) or into hearts for Valentine’s Day, and place on parchment paper to dry overnight.
    4. Fill small clear bowls with vinegar.

    My “rocks” turned gray when they were dry!
  • Have your kids drop the rocks into the bowl.

  • My son dropped a round rock into the first bowl

    They will see the rocks dissolve with lots of fizzing and foaming, and then find the hidden surprise in the bowl!

    The first surprise was a ball hidden inside the round rock!
    Next he placed a heart shaped rock into the second bowl of vinegar (baby sister is finding this experiment fascinating too!)
    He found a penny hidden inside the heart rock!

    What happened:

    The baking soda and water do not react with each other because the baking soda is a base and water is neutral. They can however create a dough because of the combination of liquid and solid. The dough will solidify as it dries because some of the water evaporates and is absorbed in the baking soda.

    When the “rocks” are dropped into the vinegar a chemical reaction takes place that releases carbon dioxide gas. This CO2 gas creates the bubbles that are observed as foam in the experiment. The “rocks” quickly dissolve in the liquid and the toy is revealed.

    I hope you and your children enjoy these Valentine’s Day themed chemistry experiments as much as my kids and I did!

    I wish you Happy Valentine’s Day with your loves (whether that be your significant other, children, chemistry, or maybe all the of the above like me!). <3


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