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Learn how to inflate a balloon in this fun science experiment using these common kitchen ingredients! Balloons inflated this way are filled with carbon dioxide produced by the two ingredients reacting. They do not contain helium, so they will not float.

Part 1
Part 1 of 2:

Inflating the Balloon

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  1. Choose a plastic water bottle, or another bottle with a narrow neck. Pour 1–2 inches (2.5–5 cm) of vinegar into the bottle, using a funnel if you have one. Use white vinegar, also called distilled vinegar, for the best result.[1]
    • You can try this with any kind of vinegar, but the inflation might take longer or require more vinegar to work. Other types of vinegar tend to be more expensive as well.
    • Vinegar can damage metal containers, potentially adding an unpleasant taste to food and drink stored in that container. If you have no plastic bottles, use a high-quality stainless steel bottle to minimize the chance of this happening. Weakening the vinegar with an equal amount of water might also help, and won't prevent the balloon from inflating.[2]
  2. You can use any shape and color of balloon. Hold it loosely by the neck, with the open side of the balloon facing towards you. Fit a funnel into the neck if you have one, then pour about two tablespoons (30 mL) baking soda into the balloon, or just fill the balloon about halfway full.[3]
    • If you don't have a funnel, you can place a plastic straw into a pile of baking soda, put your finger over the top hole of the straw, then poke the straw into the balloon and lift your finger. Tap the straw to get the baking soda to fall out, and repeat until the balloon is at least 1/3 of the way full.[4]
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  3. Be careful not to spill the baking soda while you do this. Hold the balloon's neck with both hands and stretch it over the top of the plastic bottle containing vinegar. Have a friend keep the bottle steady if the table or bottle is wobbly.[5]
  4. The baking soda should fall out of the balloon, through the neck of the bottle, and into the vinegar at the bottom. Here, the two chemicals will fizz and react, turning into other chemicals. One of these is carbon dioxide, a gas, which will rise up and inflate the balloon.[6]
    • Shake the bottle gently to mix the two ingredients if there's not much fizzing.
  5. If the fizzing has stopped and the balloon still hasn't inflated after you count to 100, empty out the bottle and try again with more vinegar and baking soda. The stuff left in the bottle has turned into other chemicals, mostly water, so it can't be used again.
    • Don't go overboard. The bottle should never be more than about 1/3 full of vinegar.
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Part 2
Part 2 of 2:

Grasping how the Process Works

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  1. Just about everything around you is made up of molecules, or different types of substances. Often, two kinds of molecules react with each other, breaking up and forming different molecules out of the pieces.
  2. The reactants, or substances that reacted with each other in the fizzy reaction you saw, are baking soda and vinegar. Unlike many ingredients in your kitchen, both of these are simple chemicals, not complicated mixtures of many chemicals:[7]
    • Baking soda is another word for the molecule sodium bicarbonate.
    • White vinegar is a mixture of acetic acid and water. Only the acetic acid reacts with the baking soda.
  3. Baking soda is a type of substance called a base. Vinegar, or acetic acid, is a type of substance called an acid. Bases and acids react with each other, partially breaking apart and forming different substances. This is described as "neutralization" because the end result is neither a base nor an acid. In this case, the new substances are water, a kind of salt, and carbon dioxide.[8] Carbon dioxide, a gas, leaves the liquid mixture and expands throughout the bottle and the balloon, inflating it.
    • Although the definition of acid and base can get complicated, you can compare the differences between the original substances and the "neutralized" result to see there are obvious changes. For instance, vinegar has a strong smell and can be used to dissolve grime and dirt. After being mixed with baking soda, it smells much less strongly and is no more effective at cleaning than water is.
  4. If you're familiar with some chemistry, or curious about how scientists describe reactions, the formula below describes the reaction between sodium bicarbonate NaHCO3 and acetic acid HC2H3O2(aq). Can you figure out how each molecule splits apart and reforms?
    • NaHCO3 + HC2H3O2(aq) → NaC2H3O2(aq) + H2O(l) + CO2(g)
    • The letters in parentheses show the state the chemicals are in during and after the reaction: (g)as, (l)iquid, or (aq)ueous. "Aqueous" means the chemical is dissolved in water.
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Community Q&A

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  • Question
    What happens if I change the bottle size?
    Community Answer
    Community Answer
    If you reduce the bottle size (volume) without changing the amount of soda and vinegar, then the balloon will blow faster and bigger.
  • Question
    Does it matter how much baking soda I put in the bottle?
    Community Answer
    Community Answer
    Yes, because if you put too much it will pop and if you put too little, it will not inflate.
  • Question
    If the balloon is thick and difficult to blow up, will this still work?
    Community Answer
    Community Answer
    Yes, it should still work correctly.
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Tips

  • This method can also be used in homemade cardboard or plastic rockets and you can make them go a long way if ingredients are out right. The reason it blows up is because the reaction creates gas, and the pressure builds up.
  • You can use lime juice instead of vinegar.
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Warnings

  • If the balloon is fully inflated and the liquid is still fizzing, the balloon might be about to explode. Decide whether you have time to pull off the balloon, or whether you should just cover your face before it gets spattered!
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Things You'll Need

  • Balloon
  • Vinegar
  • Baking Soda
  • Bottle with narrow neck
  • Funnel (optional)
  • Towel

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About This Article

Tested by:
wikiHow Video Team
wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 50 people, some anonymous, worked to edit and improve it over time. This article has been viewed 413,170 times.
17 votes - 65%
Co-authors: 50
Updated: February 2, 2024
Views: 413,170
Categories: Science for Kids
Article SummaryX

To blow up a balloon with baking soda and vinegar, pour 1–2 inches of white vinegar into a plastic bottle. Next, hold a balloon loosely by the neck, fit a funnel or plastic straw into it, and pour 2 tablespoons of baking soda through it into the balloon. Then, stretch the neck of the balloon over the top of the bottle before lifting the balloon up over the bottle. The baking soda will fall out of the balloon, through the neck of the bottle, and into the vinegar. The 2 ingredients will fizz and react to create carbon dioxide, which will then inflate your balloon! If you want to learn more about the chemical reaction that occurs, keep reading!

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