Do you love seasonal science experiments? You’ll love this science experiment for kids featuring Valentine science. If you are doing this experiment at home, focus on the science of chemical reactions when doing the dancing candy hearts science experiment.
If you are doing this STEM activity in the classroom, this experiment is fifth grade NGSS aligned and fits into the chemical reaction theme. If you are learning about chemical reactions and properties of matter in February, this is the perfect Valentine science experiment!
The dancing candy heart experiment is the ultimate Valentine science project!

If your kids aren’t in fifth grade, they can still do this experiment. Even preschoolers will love completing the dancing conversation hearts science experiment.
Don’t forget to check out all of our Valentine science experiments and Valentine STEM activities!
VALENTINE SCIENCE NEXT GENERATION SCIENCE STANDARDS CHEMICAL REACTIONS TIE-IN
5-PS1-1. Develop a model to describe that matter is made of particles too small to be seen.
5-PS1-3. Make observations and measurements to identify materials based on their properties.
5-PS1-4. Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
Get our science experiment worksheet to make this activity even easier!

THE SCIENCE BEHIND THE DANCING CONVERSATION HEARTS EXPERIMENT
Unsweetened soda contains water and carbon dioxide gas to make the soda bubbly. When the bottle is sealed, you can’t see these gas bubbles. Why not? Soda is pressurized during manufacturing which prevents the gas from escaping the liquid.
But when the soda is exposed to air, the CO2 gas tries to escape because CO2 is lighter than water and air.
Even though conversation hearts are denser than the water and gas in the soda, they still contain a lot of air.
When the carbon dioxide bubbles get stuck on the edges of the candy, eventually, the gas builds up so that the candy is brought to the surface of the jar along with the CO2 gas.
When the gas releases, the candy falls back to the bottom of the jar and the process is repeated.
The dancing candy hearts stop once the CO2 has escaped from the soda.

DANCING CONVERSATION HEART SCIENCE ACTIVITY
This Valentine science activity is the perfect way to use up conversation hearts! Any brand of conversation hearts or candy hearts will work!
WHAT YOU NEED FOR THE DANCING CONVERSATION HEARTS EXPERIMENT
You will need the following supplies when doing this activity (the following links are affiliate links):
Ball Glass Mason Jar with Lid and Band, Regular Mouth, 12 JarsThe Mason Jar Scientist: 30 Jarring STEAM-Based Projects
Brachs Conversation Hearts, 16oz Bag
LaCroix Sparkling Water, Pure, 12oz Cans, 8 Pack, Naturally Essenced, 0 Calories, 0 Sweeteners, 0 Sodium
MARATHON Adanac 3000 Digital Sports Stopwatch Timer with Extra Large Display and Buttons, Water Resistant- Yellow
HOW TO DO THE CANDY HEART EXPERIMENT

Fill a jar about 3/4 of the way full with sparkling soda.
Drop in a few conversation hearts.

Start the timer.
Watch as the candy hearts start to rise to the top of the jar, then fall back to the bottom of the jar.

Calculate how long it takes each conversation heart to rise and fall in the jar, and how long it takes before the CO2 gas escapes and can no longer lift the candies to the top of the jar.

MORE SCIENCE QUESTIONS TO ASK

What other materials create CO2 when mixed?
Does altering the amount of soda or candy change what happens?
How long does it take before the converstaion hearts start dancing?
Does the reaction change if the soda is heated or cooled to nearly freezing temperatures?