This is how so much gas is trapped. A can of fizzy drink has enough gas dissolved in it to blow up a small balloon. When you open a bottle or can of fizzy drink, the pressure on the liquid suddenly ...

When you open a can of fizzy drink, the refreshing 'hiss' is the result of gas bubbles escaping from the liquid as a result of a change in the solubility of the carbon dioxide (CO2) in it.