Have you ever considered Henry's Law?
Maybe if you are taking first year chemistry or employed at a bottling plant you have. Henry's Law mathematically describes the relationship between the pressure of a gas and the amount that can be dissolved in a liquid.
It is actually quite a simple linear relationship provided that the gas doesn't react with the liquid. The more pressure applied, the more gas will dissolve. The amount of pressure and the concentration of gas stay in a direct relationship.
There are a series of Henry's Law constants for calculating the relationship. They vary from gas to gas and with temperature. For example, oxygen is much more soluble in cold water than in hot which is the reason for the little bubbles in water just before it boils.
It is also why distilled water tastes flat. No oxygen.
Carbon dioxide, on the other hand, behaves in a very different way.
It is still less soluble in hot water than cold but gaseous carbon dioxide reacts with water to form carbonic acid. A glass of water can hold a lot more carbon dioxide than oxygen. Carbon dioxide does not obey Henry's Law.
The results have been delighting consumers for years.
Carbonated water occurs naturally in a number of springs around the world. Perhaps the most famous naturally carbonated water is Perrier if the commercials are to be believed. Many of these springs form the basis for shrines or spas as sparkling water has long been credited with medicinal properties.
In 1767, Joseph Priestley invented artificially carbonated water. (He is also given co-credit for the discovery of oxygen.)
Priestley had been working with a brewery and noted that the air above the beer vat would not sustain life. Mice and other small animals exposed to the gas would suffocate so the gas was called "fixed air".
Priestley captured some of the gas by the simple method of pouring water back and forth between two bowls held above a vat. As the stream of water passed through the gas, some of the carbon dioxide dissolved. Once in the water, it reacted to give carbonic acid which allowed more carbon dioxide to dissolve.
He found that the water thus treated had a pleasant taste - a cool, refreshing drink. In 1772, he published a paper entitled: "Impregnating Water with Fixed Air" in which he described a process for making carbonated water by dripping sulphuric acid onto chalk and capturing the released gas.
As carbonated water was a remedy for a number of ailments, it didn't take long for commercial exploitation to occur. Here was a method of artificially generating the same material. In 1783, J.J. Schweppe developed a manufacturing process and Schweppes Tonic Water has born.
Nowadays, carbonated water is the basis for various pops such as Coca Cola and Pepsi. It is the fizz when you open a bottle of Mountain Dew. The rapid release of carbon dioxide through nucleation is the basis of many YouTube videos featuring soda pop fountains. (By the way, the pop doesn't have to be Diet Coke and there are many things that can facilitate the reaction besides Mentos.)
However, the original soda fountains were something completely different. The trick to carbonating water requires the introduction of carbon dioxide. This can be done with a pressurized canister. If done right, the release of the pressurized water results in a fountain. Add a little syrup and some sugar and you have a soda fountain.
The effervescence of carbonated water and its relationship to a variety of naturally carbonated spring waters resulted in the long standing association between tonic water and health.
Tonic waters and soda pops were a mainstay of pharmacies in the late 1800s as they were sold as health food. Indeed, Coca Cola was invented by a pharmacist and was originally sold as a cure for whatever ails you.
To this day, tonic water is still used to treat mild stomach discomfort. The carbonation neutralizes excess stomach acid and the result burps help to relieve any pressure.
The really interesting side of tonic water and soda pop, though, is why we enjoy drinking it. Neurologists have determined that it activates the same pain sensors in our nasal cavity as mustard and horseradish.
The fizz in water invokes two distinct sensations. The acidity results in the water tasting sour and in making the throat burn. Scientists have even isolated the enzymes involved.
No doubt about it, drinking pop is painful but it has also been shown to control bacteria which is why it is good for you. It can cure an upset stomach.
Carbonation may not follow Henry's Law but carbonated water is definitely a tonic for all sorts of stomach maladies.
