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From Fizz To Flat: The Science Of Soda Pop

"Soda", "pop", or "cola." There's a lot of science behind the fizz no matter what we call our beloved drink.

cold diet coke can

Photo: Tom (Flickr)

Soda Pop tastes better when it's been in the refrigerator.

While it might be socially acceptable for food lovers to discuss the care of the finest wines, or the best way to brew gourmet coffee, what if your favorite beverage happens to be soda pop?

Chances are a gourmet wouldn’t have a lot to say about this topic. Well, don’t worry. It’s A Moment of Science to the rescue, as we take a practical approach to the chemistry of fizz.

What Is Soda?

Soda is fizzy because the gas carbon dioxide, or CO2, is dissolved into the sweet, syrupy liquid. Without this carbon dioxide your drink would be flat and unpleasant.

Unfortunately, carbon dioxide molecules have a natural tendency to leave any liquid, popping through the surface and escaping forever as a gas. The trick to preparing the perfect pop, therefore, is to keep as much of this dissolved CO2 inside the liquid as possible.

Why Do We Put Soda In The Fridge?

One way to do this is to refrigerate your soda as cold as possible, although you don’t want to freeze it. When soda is cold, the carbon dioxide molecules have less energy to escape, and cold soda can hold more CO2.

That’s why soda that you buy cold will be fizzier than soda that’s been sitting unrefrigerated on the store’s shelves.

Extra Carbon Dioxide

Another strategy, which the soda bottler might do at the factory, is to load up the air at the top of the container with extra carbon dioxide, or increase the pressure of this gas.

This will make it harder for the CO2 to escape, and also increase the rate at which these molecules are returned to the soda.

  • Francisco

    Also, Soda Pop has carbon dioxide so when you open it for the first time, the pressure difference makes it loose some temperature. Funny how physics works

  • Ally

    I agree with the author. Soda without CO2 will definitely make the drink plain. Diet coke is amazing since it is not only give you great taste like other carbonated drinks but also good at keeping you healthy. Another same type soda drinks by coca cola is coke zero. Both drinks are the 90% same to each other, low calories and good for health but what differentiate these two diet coke and coke zero is just the name. Diet coke tends to target the old generations and coke zero tends to target young generation and also man because you know, with name of DIET man will think it is girly and not so cool to them. whatever. The things diet coke and coke zero are good for health. Cheers~


  • Guest

    You should use fizz saver!!!!!!!!This is only $5 and fit into your fridge. more info. here:

  • Guest


  • Ruka Yan

    You definetly should use fizz saver!!!!!!!!This is only $5 and fit into your fridge. more info. here:

  • im not a hater, just a comment

    whatever, i think this was completely useless

  • Lorrenzita

    Ally, you have obviously had more than your share f diet products. You should have a brain scan for cancer. Diet products are good for you? Really? After your brain scan, you should go do some research that doesn’t include propaganda, real research. Then, if you believe in God, you need to go pray for forgiveness for saying that man-made things (Aspartame, for one) are better than things (real sugar) that God made.

  • Natalie W

    There is nothing healthy about Diet Coke …. it is worse for you than regular pop. I drink kombucha or sparkling water when I need a fizzy drink. If you are desperate for a pop try Hansens or Blue Sky or if you must have diet pop due to diabetes or other conditions drink pop sweetened with stevia.

  • DeltaBrane

    Does the content or concentration of a liquid change how quickly CO2 (under otherwise identical conditions) comes out of solution? For instance does seltzer water go flat quicker than Coke?

  • Alexa Navas

    Hi i’m doing a science fair project and I need help.My question is which soda has fizz that last longer? So can you help me?

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