Here's why:
Physical Change: A physical change involves a change in the form or appearance of a substance without changing its chemical composition. In the case of Pop Rocks and soda, the reaction results in the formation of carbon dioxide gas bubbles, which causes the candy to fizz and erupt. This change is physical because the chemical composition of the candy and soda remains the same.
No Chemical Reaction: A chemical reaction, on the other hand, involves the transformation of one or more substances into one or more different substances. Chemical reactions are characterized by the breaking and forming of chemical bonds, which results in a change in the chemical composition of the substances involved. In the case of Pop Rocks and soda, there is no chemical reaction taking place. The candy and soda do not chemically react with each other to form new substances.
Therefore, the reaction between Pop Rocks candy and soda is a physical change, specifically the formation of carbon dioxide gas bubbles, rather than a chemical change.