What causes the reaction of a cork to fly off a bottle filled with soda?

Answer 1

It's not a reaction, it's what happens when you have a build up of pressure. In a carbonated drink like soda the carbon dioxide is dissolved in the water under pressure. If the pressure is released then you see bubbles. If the dissolve gas particles are given enough energy to become gas they can increase the pressure enough to blow a cork out.

Here's an analogy that might help:

Imagine you are on a plane. Every seat is taken and no more people can get on board. The plane is sealed up. The people are the dissolved gas particles. They stay in their seats and none can 'escape'. At the airport a door is opened and people start to get off. It's a controlled release and once outside they all wander off in different directions. Eventually the plane will empty - or the drink become flat.

If, however, at some point during the exiting someone blocks the end of the stairway, then you'll have some 'escaped' people, some people still in the plane (dissolved) and some on the steps, neither escaped or dissolved. These are the carbon dioxide particles that are stuck in the gas space above the drink in the bottle. The people on the stairs stop anyone else in the plane from getting out - so the drink is still fizzy.

If you give the people a really strong desire to leave the plane, like a fire alarm, then they will leave by any exit possible, like an emergency exit. If the only available exit is the blocked stairway then they'll rush at it and push past as hard as possible. Like our energised bubbles pushing past the cork.