If the children in your life are anything like mine, they LOVE to experiment! It is so fun to watch their facial expressions, as they experience the chemical reactions that take place, such as in this self-inflating balloon experiment. It’s a mixture of pure joy and wonder!
In this self-inflating balloon experiment, children use an acid-base reaction to inflate a balloon. However, there are countless variations that can be done, which I list below.
In addition, this experiment can be performed by children of all ages. Even my 2½ year old had a blast inflating her balloon several times! Simply increase or decrease the difficulty or comparisons being made in this experiment, depending on the age of the child.
Supplies Needed
Chances are, you have all you need to perform this experiment right in your own home! The equipment and materials lists are super simple.
The equipment recommended for this experiment includes:
The only two materials needed for this experiment are:
The chemicals in this experiment are non-toxic and inexpensive. Therefore, this is a great project for scientists of all ages to perform repeatedly!
The Experiment
To begin the experiment, first add about ¼ cup of vinegar to an 8 to 12 ounce bottle with a narrow opening. Refrain from adding too much vinegar, as this will cause the reaction to fizz up into the balloon.
Next, pour 1 tablespoons of baking soda into a balloon. It helps to use a funnel to perform this step. We also found it helpful to use a toothpick to stir the baking soda into the funnel and break up any clumps that may have occurred.
Once the baking soda is in the balloon, affix the balloon to the mouth of the bottle, being careful not to get any baking soda into the bottle, just yet.
Finally, lift the balloon up into the air, emptying the baking soda into the bottle. Watch the balloon inflate, as the baking soda mixes with the vinegar!
Tip: Have your little scientist perform this experiment on a tray or in a shallow baking dish of some sort, just in case the bottle tips over and the mixture spills.
The Science
The balloon inflates as a result of a chemical reaction between baking soda (sodium bicarbonate, a base) and vinegar (acetic acid), which produces an unstable carbonic acid. The carbonic acid immediately separates into water and carbon dioxide (CO2). As pressure builds up in the bottle, the CO2 bubbles out of the bottle and into the balloon, causing it to expand. The more CO2 that is created, the larger the balloon will expand!
Another interesting thing to mention is that the acid-base reaction is endothermic, which means the chemical reaction makes the mixture feel colder.
Self-Inflating Balloon Experiment Variations
Children will have a blast testing all sorts of variations to this experiment. Try these variations to see which chemical reaction is best at inflating a balloon! To make the self-inflating balloon experiment even more educational, record your hypotheses and analyze the effects.
1. Size
Consider measuring the size of the balloon before and after it has inflated. Draw a 1 cm long black line on the balloon with a marker before adding the baking soda. After performing the experiment, record the time it took for the line to expand to 5 cm in length.
2. Change the Acid
Predict what will happen if you change the amount of vinegar. (i.e. 2 tablespoons, ½ cup, etc.) Does this effect how long it takes the line to get to 5 cm in length?
Does it change the reaction if you use lemon juice, soda, or citric acid dissolved in water as an acid, instead of distilled white vinegar?
Predict what will happen if you use hot water instead of distilled white vinegar. (Be sure to have an adult handle the hot water for little ones!)
3. Change the Base
Predict what will happen if you change the amount of baking soda. (i.e. 1 teaspoon, 2 tablespoons, etc.) Does this effect how long it takes the line to get to 5 cm in length?
Does it change the reaction if you use laundry detergent, an Alka-Seltzer tablet or a Mentos tablet as a base, instead of baking soda?
4. Temperature
Consider taking the temperature of the liquid in the bottle before and after the reaction. What has happened?
Predict what will happen if you change the temperature of the vinegar or other acid. (i.e. refrigerated vs. room temperature, etc.) Does this effect how long it takes the line to get to 5 cm in length?
5. Other Ways?
In what other way(s) can you change the amount of CO2 emanating from the chemical reaction to make the balloon inflate even more? Consider changing the chemicals, the size of the bottle, and the size of the balloon.
Tip: While performing this self-inflating balloon experiment, remember to keep all other variables the same.
Acid-base experiments are fun to experiment with at any time of the year. Fortunately, baking soda and vinegar are so inexpensive, children can experiment again and again and again! So, stock up on these supplies. You never know when you will need them for easy entertaining and loads of learning! Good luck!
Self-Inflating Balloon Experiment
Equipment
- Balloon
- Funnel
- Small measuring cup
- 8 – 12 oz. Bottle
Materials
- ¼ Cup White Vinegar
- 1 Tbsp Baking Soda
Instructions
- Pour white vinegar into a bottle.
- Use a funnel to pour baking soda into a balloon.
- Attach the balloon to the mouth of the bottle. Be careful not to get any baking soda into the bottle until you are ready to proceed with the experiment.
- Hold the balloon up and let the baking soda pour down into the bottle. Watch the balloon expand, as gasses fill the balloon!
Have you made a balloon self-inflate with your kids or grandkids? Please share below.
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