A soft drink (also called soda, pop, coke, soda pop, fizzy drink, or carbonated beverage) is a non-alcoholic beverage that typically contains carbonated water, a sweetening agent, and a flavoring agent. The sweetening agent may be sugar, high-fructose corn syrup, or a sugar substitute(in the case of diet drinks). A soft drink may also contain caffeine or fruit juice. Products such as energy drinks, Kool-Aid, and pure juice are not considered to be soft drinks. Other beverages not considered to be soft drinks are hot chocolate, hot tea, coffee, milk, milkshakes, and schorle. Soft drinks are called "soft" in contrast to "hard drinks" (alcoholic beverages). Small amounts of alcohol may be present in a soft drink, but the alcohol content must be less than 0.5% of the total volume if the drink is to be considered non-alcoholic. Widely sold soft drink flavors are cola, lemon-lime, root beer, orange, grape, vanilla, ginger ale, fruit punch, sparkling lemonade, squash, and flavored water. Soft drinks may be served chilled or at room temperature. They are rarely heated.
Soft drinks displayed on supermarket shelves.
In late 18th century, scientists made important progress in replicating naturally carbonated mineral waters. In 1767, Englishman Joseph Priestley first discovered a method of infusing water with carbon dioxide to make carbonated water which has 3.4 mg in the drink  when he suspended a bowl of distilled water above a beer vat at a local brewery in Leeds, England. His invention of carbonated water, (also known as soda water), is the major and defining component of most soft drinks. Priestley found water thus treated had a pleasant taste, and he offered it to friends as a refreshing drink. In 1772, Priestley published a paper entitled Impregnating Water with Fixed Air in which he describes dripping oil of vitriol (or sulfuric acid as it is now called) onto chalk to produce carbon dioxide gas,...