What's the Deal With Pop Rocks?

Ever since Pop Rocks have been introduced to the candy market in 1995, they have mystified children and candy eaters alike with the wonderful crackling feeling as the candy pops in your mouth. So what causes this mysterious crackling sensation?

The answer is tiny pockets of carbon dioxide (CO2). The sugar, corn syrup, and artificial flavoring is heated in a pressure cooker until boiling, then CO2 is injected at 600 psi, and the whole mixture is cooled to 25 degrees Celsius, causing small pockets of CO2 to form. When the pressure is released, the candy shatters into rocks, but the little bubbles of CO2 stay trapped in these rocks. We wanted to find out exactly how much CO2 was trapped in these little candies, so we conducted an experiment to find exactly how much there was.

Our procedure was simple, a sample of 2.001g of Pop Rocks was measured, and dissolved into a beaker with 100 mL of water. A magnetic stirring rod was placed in the mixture, and the beaker was placed on the magnetic stir plate. The stir rod mixed until the solution was properly dissolved.

The temperature was taken with a temperature probe, and the beaker was weighed and recorded. The barometric pressure was taken with an app from a phone.

Beaker Mass Before Solution is Formed

186.471 g

Beaker Mass After Solution is Formed

186.400 g

Mass of CO2 Lost

0.07 g

As you can see we lost about 0.07g of CO2.

When we put our numbers into the ideal gas law formula, we come out with .05 L of CO2.

If we take our .05 L of CO2 and divide it by our original 2.001 grams of Pop Rocks, we end up with .02 L of CO2 to grams of Pop Rocks.