Fizzy Homemade Valentines Cards

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About a year ago I made some homemade valentines cards for my youngest son to give out to his class at preschool. We made valentine’s cards that included a small baking soda heart glued on, and made them a few days in advance, just to make sure they had time dry. The day of his valentine’s day class party, we carefully placed his cards in a box, and headed off to school. But when we got there, I realized several of the baking soda hearts had broken apart. Thankfully, my son didn’t notice, and he cheerfully delivered his cards to his teacher. I, on the other hand, was deteremined to find a way to re-engineer the handmade valentines cards to prevent the hearts from breaking again.

Create explosive homemade valentines cards! Using materials at home, your kids will love passing out these valentines to their friends.

Re-engineered Homemade Valentines Cards

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After spending some time thinking about our broken hearts, I realized what we needed was a binder. In chemistry, a binder is a substance that makes things stick together. The simplest example of a binder is glue, so I added some white glue to my heart mixture, and voila! I had a much stronger heart!


Step 1: Pour 4T of hot water into small bowl.

Step 2: Add 1/2 Tablespoon of glue to the hot water, and stir until the glue is mixed well.

Step 3: Add 10 drops of red food coloring to the glue/water mixture.

Step 4: Add 9T of baking soda into the red glue/water mixture, a little bit at a time. Mix well.

Baking soda, glue, water mixture.

Step 5: Place the heart cookie cutter on a piece of wax paper, and pour a little bit of the mixture from step 4 into the heart. Leave the cookie cutter in place for 5 minutes.

Pouring mixture into cookie cutter.
Mixture in cookie cutter.

Step 6: Remove the cookie cutter, place it on a new place on the wax paper, and repeat step 5 until you have the number of valentines you would like to make. Leave the hearts to dry overnight.

Making lots of explosive hearts!

Step 7: Fold the red construction paper in half, then in fourths. Unfold the paper.

Red piece of paper folded into 8 sections.

Step 8: Cut along the creases of the paper to make eight rectangles.

Step 9: Print the valentines below onto white cardstock paper. Cut out all eight valentines.

Front of homemade valentines card.

Step 10: Glue each valentine from step 9 onto one side of a piece of cut construction paper from step 8.

Step 11: Print the instructions for the hearts, below:

Back of homemade valentines card.

Step 12: Cutout the printed instructions from step 11, and glue them onto the back of each valentine.

Back of homemade valentines card.

Step 13: Glue the dried hearts on the front of the card.

Finished homemade valentines card!

We made 33 valentines for my boys’ classes, and each one was so excited to give them to their friends!

Back at home, we decided to try out some of our leftover hearts, and boy were we in for a surprise! The binder in our hearts (the glue) seem to prevent the bubbles from our baking soda and vinegar reaction from popping! In other words, the addition of a binder to our mixture increased the surface tension of the bubbles in the reaction! Our unexpected result gave us bigger and longer lasting bubble explosions!

First we filled a cup with 1/2 cup of vinegar then dropped a heart in to see what would happen.

We wanted a bigger reaction, so we experimented with starting more vinegar. For our second reaction, we started with 3/4 cup of vinegar.

Wow! The reaction was so much bigger with a little more vinegar. We even learned we could help the reaction by swirling the cup. I love that our homemade valentines cards don’t include any candy, and show kids the fun of chemistry!

For other valentine’s day ideas, try some of these!

35 Valentine’s Day Science Experiments!
Heart Themed STEAM/STEM Activities
DIY Valentine using Water Science
Make a Light up Card with a Simple Circuit!

Or if you would like more chemistry activities, here’s a fun list!

Brown Egg in Vinegar Experiment
Grow Gold Overnight! A fun experiment for kids
Grow a Pot of Gold! Crystal Science Experiment
Crystal Science Experiment at Home
The Anti-Climatic Volcano Experiment