Experiment: Pop Rocks Expander

By Mei Yee

For this weeks experiment, we are doing “Pop Rocks Expander.” This one only requires four things; balloons, bottles of soda, Pop Rocks candy, and a funnel. You can see we are not using the Pop Rocks brand itself, as I couldn't find any. However, this brand is just as good, or that is what my kids tell me.

I did look up the ingredients list as I was worried about any differences that could affect the experiment. The only difference between the two was that the Pop Rocks brand contains lactose and the Tiltay brand does not.

I’m not very knowledgeable when it comes to science. So I was curious as to how adding Pop Rocks to soda could inflate the balloon.

While looking it up, we found that carbon dioxide gas (CO2) is in both the candy and the soda. Some of the gas in the soda collects on any imperfections, dents, or bumps on the candy. Some of the gas escapes from the water and corn syrup that holds it and moves upward. It fills the space at the top of the bottle and then moves up into the balloon as the volume of CO2 increases.

So we decided to try this and see how well the balloon inflates. The steps are below!

First, take the funnel and insert it into the balloon.

Next, take one pack of Pop Rocks, open it, and dump it into the balloon using the funnel.

Then (with an adult's help), wrap the balloon's opening over the opening of the soda bottle. (The balloon should hang to the side until you’re ready for the next step.)

Grab the end of the balloon (the lowest hanging point) and lift it to allow the Pop Rocks to fall into the soda.

Watch as the balloon expands!

The balloons didn't blow up as much as the ones in the experiment we saw, but the girls still had fun testing it out.

(The balloons we used didn't seem to be very stretchy to begin with, that might have had something to do with it. We also noticed the sour pop rocks (the one in the middle) seemed to have the best result. Not sure it being sour had anything to do with it or not but just wanted to make a note of it for everyone!)

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