A simple experiment to show that there are really gases dissolved in water.

Luckily, my parents like to play at least as much as I do. So when I got back from doing “real science” in Bergen the other day, they picked me up at the airport and showed me their latest toys: Vacuum pumps! [edit: Not really vacuum vacuum, but at least much lower than atmospheric pressure. And apparently those pumps are sold with the original purpose of re-sealing wine bottles]

Vacuum pumps are great to show that there are actually gases dissolved in water, because oftentimes that isn’t all that obvious. But when the pressure of the head space of a bottle is decreased, gases that were happily dissolved under atmospheric pressure start coming out of solution.

Gas being bubbled out of water by decreasing the pressure of the head space of the bottle.

Here is a comparison of normal tap water and sparkling water (sparkling water obviously containing much more dissolved CO2 than tap water, hence more bubbling).