Ever wonder what makes drinks like soda (or is it pop?) bubbly? And why don’t they stay bubbly all the time?

The secret to soda and other “bubbly” drinks is carbonation. Carbonation occurs when carbon dioxide gas — CO2 — is dissolved in water. Carbonation requires high pressure and low temperatures.

Drink makers add carbonated water to various flavorings to make the wide variety of carbonated drinks sold around the world today. When a carbonated drink is in a sealed container, such as a can or a bottle, there are few bubbles because the contents are under high pressure.

High pressure keeps the carbon dioxide that is dissolved in the water in the drink. When the bottle or can is opened, however, this pressure is reduced quickly. This allows the carbon dioxide to escape from the water and return to a gas.

When this happens, the gas carbon dioxide escapes from the liquid in the form of fizzy bubbles. The sound you hear when you pop open a soda is the sound of carbon dioxide gas molecules rushing back into the air.

When carbon dioxide is dissolved in water, it also produces a weak acid called carbonic acid. Carbonic acid gives bubbly drinks their characteristic tangy flavor that you notice is missing when, for example, a soda goes flat.

After you open a carbonated drink, carbon dioxide continues to escape from the liquid and returns to the air. Over time, most of the carbon dioxide escapes and the drink goes totally flat.

That’s why you should recap soda bottles after you open them to keep the soda from going flat too soon. Recapping a soda bottle increases pressure and slows the speed with which carbon dioxide escapes.

Carbonated water has been around for a long time. Hundreds of years ago, scientists learned that it was carbon dioxide that was responsible for the bubbles in natural mineral water. In 1767, Joseph Priestly created the first drinkable man-made glass of carbonated water.

Soda fountains became popular fixtures in American pharmacies in the mid-19th century. Drinking either natural or man-made carbonated mineral water was thought to promote health. Eventually, pharmacists began to add flavorings to mineral water and the drinks we know as sodas (or pops!) soon followed.

Carbon dioxide has another unique use. You’ve already learned about its liquid and gas forms that exist in the process of carbonation. Carbon dioxide can also be frozen into a solid. When this happens, it’s called dry ice!


36 Join the Discussion

1 Star2 Stars3 Stars4 Stars5 Stars  (16 votes, avg. 4.75 out of 5)
  1. Dear Wonderopolis,
    Me and Rahul got it again! Yeah us! I think tomorrow’s wonder will be why do we drop the big ball on New Year’s Eve? Happy New Year, wonderopolis!

    • You guys are GREAT guessers, Paige! Thank you for visiting this Wonder of the Day® and for leaving us this awesome comment. Happy New Year to you, too! :-)

  2. This is a great topic and a great clue I have no idea what it will be about!! I cant wait until next year’s new wonders!! Happy New years!! :-)

    • We like your enthusiasm for Wonderopolis, Rebecca! We’re really happy to hear that you’ll be hanging out with us and exploring lots of Wonders in the new year! We hope you have an AMAZING 2012! :-)

  3. Hi, my name is Jack from Mrs. Caplin’s class. I always wondered if you guys were going to write about a wonder on Why Are Some Drinks Bubbly and sure enough you did! I have been thinking about this for a long time and now I just learned why. How come when you put ice in the drink makes it more bubbly? I think this is one of the best wonders yet! Keep up with the fantastic wonders!!!!!

    • Hello, Jack! Thanks for visiting this Wonder of the Day®! Did you know that your comment is the FIRST Wonderopolis comment of 2012? Way to go! We like your question about the ice, but we’re not sure about the answer. Looks like we’ll all have to do some more WONDERing to find out, won’t we? Happy New Year! :-)

    • Hey, Missy! We see you visited this Wonder of the Day® to learn what makes certain drinks bubbly! Thank you for hanging out in Wonderopolis and for leaving us this COOL comment! :-)

    I love Diet Coke, and I’ve also done the experiment last year with the Mentos! It was so cool!

    • The video with all the coordinated sprays of Diet Coke and Mentos was really cool, wasn’t it, Ninja Girl? Those guys were GREAT! :-)

  5. This is such a phenomenal wonder! I think that it is so cool that carbonation can make a whole drink fizzy and bubbly! Also, I had no idea that the sound that you hear when you open a can of soda is the sound of the carbon dioxide molecules rushing back into the air! That was so cool! You added so many other facts including that carbonic acid gives bubbly drinks their delicious flavor! I was so surprised while watching the video, because it was so cool that they could do all of those amazing explosions with Diet Coke and Mentos! It almost seemed like fireworks!!!!! It was really cool that they could use 101 2-liter bottles of Diet Coke and 523 Mentos in all of those fascinating explosions! This wonder was TERRIFIC!!!!!

    • We really appreciate your BUBBLY personality and enthusiasm for this Wonder of the Day®, Jack! It sounds like you learned a LOT about carbonation! Thanks for leaving us a comment to share! :-)

  6. I have actually wondered why pop is bubbly and you answered my “wonder”. I am glad I read this wonder! This wonder answered my question and I even learned some new and interesting things, too! I really thought it was interesting that there is a such thing as a soda fountain, I never knew there was a such thing as that!!!


    • Thanks for leaving us this comment today to let us know some of the cool things you learned by visiting this Wonder of the Day®, Hannah! YOU ROCK! :-)

    • We’re pretty sure they had to practice a LOT before they could perform the whole start-to-finish routine we saw in the video, Cole! It was so coordinated and sooooooo cool (and minty fresh)! :-)

  7. I think this wonder of the Day is super interesting because in the video, they do really cool things such as they shoot that stuff everywhere and they have an experiment in there. I learned some things, too. One of things that I learned is the pop (or soda!!) is carbonated water that has flavored stuff inside it.

    • We LOVE hearing all the cool things our Wonder Friends (like you!) learn when they visit the Wonders of the Day, Abby! Thank you for sharing what YOU learned today! :-)

  8. Wonderopolis,

    WOW this is so interesting! I was very curious about this wonder the first minute I saw it! I have a soda machine at home and thought that it was the Carbon dioxide because when we insert the bottle and press the button to put in carbon dioxide, when we take it out it makes that fizzy noise!! To newly learned vocabulary words that I learned are carbonation and tangy! That is interest that when you open the pop bottle it releases the carbon dioxide! I just recently learned that! It may be smarter to buy the pop with lids on it! To go even farther… Who do you think invented pop machines for our homes?


    • WOW! It’s so cool that you have a soda machine at home, Team Unger #12! It must be SUPER fun to make your own sodas and create your own flavor combinations! We think that may be why someone invented the in-home soda machine. Those machines give people more choices over the types of sodas they make and drink. They allow people to control the amount of sugars or flavorings they add to their sodas, and lots of people see a benefit in having that choice! Thanks for sharing your GREAT comment with us! :-)

  9. I once tried this experiment with the diet coke and the mentos at science camp. It
    was like a diet coke fountain!

    • COOL, Julie! Thank you for sharing that you have tried the experiment! We appreciate hearing about that personal connection you have to this Wonder of the Day®! :-)

    • Aliya,

      As you will discover in today’s Wonder, Motown is actually Detroit, Michigan! It’s a city with a very interesting musical history. :)

    • Aliya,

      That’s great! We love to hear that our Wonder Friends are experimenting, learning and WONDERING every day! :)

    • Hi Eriaunna! Thanks for WONDERing with us! It’s a chemical reaction with the soda so you have to WONDER about other types of chemical reactions! :)

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>


  • Wonderopolis on Facebook
  • Wonderopolis on Pinterest
  • Print

Have you ever wondered…

  • Why are some drinks bubbly?
  • What is carbonation?
  • Why do sodas go flat?

Wonder Gallery

Try It Out

Ready to see carbon dioxide in action? There’s no better way to put what you’ve learned into action than by doing some fun and simple science experiments.

Take a look at the experiments linked to below. Pick one or two and give them a try. Ask a friend or family member to help you.

  • Diet Coke and Mentos

Have you ever seen a Diet Coke and Mentos experiment? Watch the linked video and see if you can talk an adult into helping you replicate the experiment at home!

  • Soda Balloon

To see firsthand how carbon dioxide will continue to escape from an open soda bottle, try the Soda Balloon experiment. Watch the linked video and then give it a try in your own kitchen!

  • Burp Trap

This last experiment is just a good excuse to drink soda and burp. Who says science can’t be fun? All you need to do is drink a can of diet soda quickly — without burping. As soon as you’re finished, lie down on your back and try to burp. You’ll find that it’s not that easy. If you sit up, though, you’ll be burping in no time. This is because carbon dioxide gas rises. When you’re lying down, the gas rises to the top of your stomach, near your belly button. To burp, the gas needs to be near the top of your throat…which is exactly where it goes as soon as you sit up!


Still Wondering

In Illuminations’ Beverage Sharing and Serving lesson, children determine, using a nonstandard cup or plastic drinking container, the minimum amount of fruit drink needed to serve class members.


Wonder Categories/Tags

Wonder What’s Next?

Tomorrow’s Wonder of the Day is a secret. You’ll just have to wait until next year to find out!

Upload a Photo or Paste the URL of a YouTube or SchoolTube Video.