Which is heavier a bottle of fizzy cola or flat cola?

Here's why:

* Carbon dioxide (CO2): Fizzy cola contains dissolved carbon dioxide gas. This gas contributes to the weight of the bottle.

* Density: The dissolved CO2 makes the liquid in the fizzy cola denser than flat cola.

Therefore, even though the volume of the liquid is the same, the fizzy cola will weigh slightly more due to the added weight of the dissolved CO2.