It’s fizzy because the gas carbon dioxide is pumped into it. Before you open the bottle, most of the gas is trapped invisibly in the drink. But when you unscrew the top, the gas is released and forms thousands of bubbles.
Making a fizz
Why not try your own fizzy experiment? Add baking powder to water and watch what happens. When it mixes with water, it makes bubbles of carbon dioxide, too.
When you breath out, carbon dioxide is one of the gases in your breath.
What do you give a sick lemon?