If I shake up a bottle of drink why does the pressure increase?

Question

In other words why does the gas come out of the drink

Answer 1

I think "Robert *" has got the best answer to this question. However, I'd like to add the following:
If you've just put the cap back on the bottle, shaking it causes the build-up of pressure to happen faster. Basically, CO2 will be released from the drink until the pressure of CO2 in the drink equals the (partial) pressure of CO2 in the mixture of gases. Normally this takes a while, but once you've reached that pressure, you won't be able to exceed it by shaking (which is why Robert * answered the way he did). Actually the pressure will slowly start to drop because of leaking through the cap.

An interesting aside is that if you try those "keep my fizziness" pumps you will find they don't work very well. This is because, even though you are increasing the total pressure in the gas above the drink, you are not adding much CO2 and hence not really affecting the partial pressure due to CO2 in the gas. It just makes the gases leak out of the bottle faster (because the total pressure is higher).

Answer 2

According to Ask Science Theatre, the pressure in the bottle does not increase when you shake it, but is still to blame for the phenomonon. In an unshaken bottle, soda occupies the bottom nine-tenths of the container, with a pocket of gas siting on top; this gas escapes with a pfffffft when you open the bottle, leaving the soda undisturbed. When you shake up the bottle, though, some of that carbon dioxide is mixed into the liquid and forms tiny bubbles. The gas still wants to escape when you open the bottle, though, but now has to muscle its way up through the soda toward the spout. In doing so, it pushes the liquid upwards, causing it to gush out of the bottle. The more you shake the bottle, the more thoroughly the carbon dioxide mixes with the soda, the greater the subsequent explosion.

Answer 3

I don't think the pressure does increase as that should be constant from the day the bottle is sealed. What you do by shaking it is start off the process of releasing the CO2 gas from the drink, hence all the bubbles, then when you take the top off or open the can the free gas, in its efforts to escape, ejects the drink too.

Answer 4

Regardless of whether it is a carbonated drink or not, the pressure will increase for three reasons:

1. If it IS carbonated, then the dissolved CO2 comes out of the liquid, creating more pressure (that one's obvious).
2. The extra kinetic energy from shaking is turned into heat energy which also increases temperature/pressure (but this is negligible, just fun to think about)

3. The shaking of any liquid even slightly viscous, will create foam, increasing the space that the liquid takes up, decreasing the amount of space left for the gases, increasing pressure.

Answer 5

The pressure does not increase when you shake it. What happens is that little bubbles of gas become entrained in the liquid. When the top is opened these gas bubbles 'seed' rapid release of dissolved carbon dioxide throughout the liquid and the consequent spurting of bubbling liquid out of the bottle.

Answer 6

The formula for sodas specifies that they be carbonated to get that fizzy taste. They use carbon gas to do this, but for the carbon gas to escape out of the liquid, they must pressurize the container so that the carbon stays in the liquid, or else you'll have "flat" soda. When you shake it, you are upsetting the equilibrium between pressure and gas, and the gas rises, causing the container to "explode" when you open it...

Answer 7

I believe it has something to do with the shaking increasing the carbonation in the drink, making less room between it and the liquid, therefore causing the violent reaction when you open it.

Answer 8

Becouse when u shake it, the molecules of the drink collides with each other quickly & strogely, so the reactions between them increase, which make the temprature of them increases so the pressure increases too

Answer 9

ymingy has it right. The CO2 coming out of solution does increase the pressure. If you let it sit for a long time, the CO2 will go back into solution and the pressure will decrease.

Answer 10

because of the gas in it