1. Dissolution of Pop Rocks: When Pop Rocks are dropped into Coca-Cola, they quickly begin to dissolve. The candy coating of Pop Rocks contains tiny pockets of carbon dioxide gas trapped inside. As the coating dissolves in the soda, these pockets are released.
2. Nucleation Sites: The dissolved sugar in Coca-Cola acts as nucleation sites for the released carbon dioxide gas. Nucleation sites are tiny particles or surfaces on which gas bubbles can form and grow. The sugar molecules in the soda provide these nucleation sites, allowing the carbon dioxide bubbles to form and expand rapidly.
3. Rapid Bubble Formation: The released carbon dioxide gas forms numerous tiny bubbles on the surface of the Pop Rocks and within the soda. The formation of these bubbles creates an effervescent effect, causing the liquid to foam and fizz.
4. Surface Tension and Expansion: The carbon dioxide bubbles trapped within the dissolving Pop Rocks candy pieces expand rapidly due to the high concentration of dissolved gas inside. This expansion causes the bubbles to push against the surface tension of the soda, creating an upward force.
5. Explosive Eruption: As more and more carbon dioxide bubbles are released and expand, the upward force becomes stronger, eventually overcoming the surface tension of the soda. This leads to a sudden and explosive release of the trapped gas, causing a fountain-like eruption of the liquid.
In essence, the combination of rapidly expanding carbon dioxide bubbles and the dissolved sugar in Coca-Cola creates an explosive reaction that results in the characteristic fizzing and eruption when Pop Rocks are added to the soda.