I have found that it is pretty hard to find Pop Rock candy nowadays, which is a shame! But, if you ever come across it, pick up a packet and a 1 liter bottle of soda and you can really see some cool stuff!
Here is what you do:
Pop Rock Experiment
Step 2: Removed the lids from our four soda bottles and put the balloon over the opening being careful not to pour the pop rocks in until all the bottles were ready.
Step 3: Lift the balloon from its side so it is able to pour the pop rocks into the soda and take a step back.
Step 4: Watch your balloon to see what happens!
The Science Behind it:
Pop Rocks have small carbon dioxide bubbles inside. That is what makes the candy “pop”. Carbonated Beverages also have carbon dioxide in them (that is what makes them carbonated). When the pop rocks are dropped into the soda the carbon dioxide is able to separate from the high fructose corn syrup (which sweetens the soda). Because the carbon dioxide has no where to go it rises up, filling up the balloon.
Want to see where I got the idea? Here it is! www.123homeschool4me.com/2015/03/pop-rock-science-experiment-for-kids.html?m=1