Soda Can Shake-Up
Have you ever wondered why shaking a soda results in a great explosion when it’s opened? What causes a 2-liter bottle of soda to go flat? Is there anything that can be done to keep fizz in a bottle of soda? Get ready to uncover some amazing soda secrets that will change your soda drinking habits.
- Cans of unopened soda. It's best to practice with clear liquids! Try club soda. It's not sticky.
- Vigorously shake a sealed can of soda.
- Invite a dinner guest to immediately open the can! Of course, most sane people will refuse the offer.
- With a little science know-how, you’ll be able to open the can without spilling a drop. The secret is to use your finger to snap the side of the can. Turn the can a quarter turn and snap again. Snap the side of the can at least 6 times before opening it.
- Here's the true test... open the can. Pssst! That sound should be music to your ears. When the can is opened, the gas simply escapes (no liquid explodes from the can), and you bow to tremendous applause.
Once you've mastered the technique, try your newly discovered skill on different kinds of soda... but watch out for diet sodas. There's no guarantee that snapping the side of a can of diet soda will keep you from getting sprayed when you open the can of shaken soda. Some scientists speculate that diet sodas contain more carbon dioxide gas while others believe that there is a unique interaction that goes on between the artificial sweetener, the preservatives, and the carbonated water. No one fully understands the reason. So, if you choose to shake up a can of diet soda... well, you're on your own.
How Does It Work?
Since the fizz in the soda is actually dissolved carbon dioxide gas, the goal is to keep as much of the gas in the bottle as possible. Soda fizzes when dissolved carbon dioxide gas is released in the form of bubbles. At the bottling plant, carbon dioxide molecules are forced into the soda in an amount that is greater than would ordinarily dissolve under atmospheric conditions. As soon as you open the bottle, most of the excess gas escapes into the room – that’s a given! So, it’s your job to find a way to keep the remaining gas in the liquid.
Shaking the unopened can of soda causes bubbles of carbon dioxide to line the inside walls of the can. When you open the can, the pressure in the can goes down and the volume of each bubble goes up (Boyle’s Law). Whoosh! The quickly expanding bubbles force the liquid that rests above it out of the can.
Most people have learned to tap the top of the can before opening it. Scientifically speaking, this does nothing. The trick is to dislodge the bubbles from the side walls and bottom of the can so they can float to the top of the can (because gas is lighter than a liquid). Once the bubbles are at the top of the can there will only be a small amount of liquid blocking their escape when you open the can. As a result, the soda doesn't spray. Remember, snap the side instead of tapping the top.
- Absolutely misleading Review by Dre
This is not science. It is hearsay. Tapping the can does not dislodge enough bubbles to affect anything. On the contrary, if you're tapping hard enough to dislodge the bubbles, you are more than likely creating more in the process.
The reason that it works is that the entire process takes a long time. Since it normally takes around 20-30 seconds for the bubbles to rise up on their own, tapping the can from 12 different directions accomplishes the same thing as waiting...with the added effect that you look like an idiot doing it.
You might very well be correct about the tapping of the can not accomplishing anything. But, you may also be wrong, as well. The truth is that there is no proof either way. If you do some experimenting with it, share it with us in a video! Keep experimenting!
-Steve Spangler Science Web Team
(Posted on August 8, 2012)
- kewl Review by asdasd
it was a really easy for last minute people like me. it also gives you the excuse of drinking the soda. ;)
(Posted on March 24, 2010)
- Good Review by Teri Withers
I tried this experiment after seeing it in a training class video and it work to a point the soda still exploded but not as bad as if I wouldnt have tapped the can.
(Posted on April 2, 2013)
- Great Experiment and Helpful Information! Review by Susanne Nichols
My daughter loved doing this experiment for her science fair project. We tried it with regular Pepsi and diet Pepsi as well. It worked great with the regular soda but not as well with the diet. (as projected) But even the diet soda exploded much less after the tapping method was applied. The diet soda just fizzed up a bit without spraying or dripping down the sides of the can like the first two diet sodas. (We had just opened the first and tapped the top of the second one.) I will remember this the next time my four year old drops a soda. lol Thanks!
(Posted on April 18, 2013)