Why does soda fizz?
The bubbles were already hiding in the drink — as dissolved carbon dioxide.
What is happening?
Manufacturers dissolve carbon dioxide in the drink under pressure. While the bottle or can stays closed, that pressure helps keep a large amount of gas dissolved.
Opening the container lowers the pressure above the liquid. Carbon dioxide then escapes from solution. Tiny scratches, fibres and particles provide places where bubbles can start to grow.
What changes it?
Warmer soda generally loses carbon dioxide more readily. Shaking does not create extra gas; it helps gas collect into bubbles and makes the pressure release much more dramatic when the container opens.
The useful idea
Everyday objects make the mechanism visible because several effects happen at once. Separating temperature, pressure, material and surface effects helps explain what you actually observe.
Try to notice this
Everyday science becomes clearer when one variable is changed at a time. Compare warm and cold conditions, a smooth and a rough surface, or a closed and an open container. Small differences often reveal which mechanism matters most.
The point is not to turn daily life into an experiment, but to connect what is visible with particles, energy, pressure and materials.