Say “I love You” with Gas Balloons!
In this simple Valentine's Day experiment, little scientists use chemistry to say "I love you!"
Simple explanation: combining baking soda (a solid) and vinegar (a liquid) creates carbon dioxide gas (the gas we breathe out) through a chemical reaction. By catching the gas, the balloon lets you see how much gas was created.
Scientists commonly describe things as being a solid, a liquid, or a gas. Solids hold their shape, liquids flow into the shape of a container, and gases, which you usually can’t see, expand out in all directions to fill a container – such as a balloon!
When an acid and base are combined, a chemical reaction occurs as each tries to neutralize the other. A byproduct of the chemical reaction is a gas. The gas is lighter than the liquid and so bubbles up through the solution – which is what causes the fizzing.
How quickly a reaction occurs is called the "reaction rate." Heat increases the reaction rate; cold decreases it.
Don’t overdo the vinegar or baking soda, as the gas could build up too quickly and send the balloon flying. This could result in vinegar and baking soda spraying into kids’ eyes. If this happens, immediately rinse with cool water. Kids should wear goggles if doing this experiment without adult supervision.
- Balloon - 1+ per student
- Empty water bottle - 1+ per student
- Vinegar - 1/2+ cup per student
- Baking soda - 1+ teaspoon per student
- Sharpie marker - class set
- Food coloring - class set
To write messages on the balloons, inflate them partially and pinch closed with your fingers. Use a permanent marker to write the message, then let the air out.
Use a funnel to add about 1 tsp. of baking soda to each balloon. In a pinch, cutting the top off of a water bottle makes a great funnel. You can also carefully scoop the baking soda directly into the balloon.
Add about 1 cup of vinegar to each empty water bottle. Adding a fill line can be helpful, especially with younger scientists.
Add food coloring to make the vinegar match the color of the balloon. (You can use this step to teach about color mixing!)
Carefully attach a baking soda balloon to each bottle. Be careful not spill any of the baking soda into the bottle, or to rip the bottom as you attach it. Try to center the balloon as much as possible. Be sure it is attached well! Younger scientists will need a lot of help with this step.
When everything is set up, have the kids tip their balloon up and shake gently to make the baking soda fall into the vinegar. The balloon will quickly inflate from the gas created. Please see the safety note above -- if you see the balloon start to over-inflate, or the bubbling liquid start to spray out, quickly remove the project from any little ones who might get the spray into their eyes.
Extension: Try changing the amounts of vinegar and baking soda, or change the temperature of the vinegar. Use the balloon to gauge how much gas is produced, and/or how quickly it is produced. Kids should wear goggles if doing this without adult supervision.