Jars and bottles are distinguished by their openings. A jar has a wide mouth, typically of the same width of the jar or very close to it. A bottle, on the other hand, has a neck which is much narrower than the body of the bottle, with a lipped mouth to facilitate pouring without spilling. Both jars and bottles have a wide range of uses, and they have been around for centuries in their basic forms.
Jars are used to store liquids or solids and are classically cylindrical, although they may also be made in the form of squares and other shapes. Like bottles, jars can be sealed in a wide variety of ways, and their design allows people to either pour out the contents, or scoop them out, depending on personal taste and the contents of the jar. Jars are also easier to stack than bottles, as they classically have flat tops, taking up less space than bottles, which must be stacked in large racks.
Bottles, on the other hand, can be used primarily to store liquids. They are not effective for solid storage because of the narrow neck, which makes it difficult to pour out the contents of the bottle, let alone get something inside. Thick liquids such as ketchup and other sauces may also be packaged in bottles, and there are a wide variety of bottle designs available, from bottles designed to keep their contents carbonated to bottles with traps for sediment. Bottles may be corked, stoppered, or sealed in other creative ways, like with a marble which pushes against a rubber gasket as long as the contents of the bottle stay carbonated.
The primary disadvantage of a bottle is its narrow neck, which makes it unsuitable for thick or chunky solids.
A jar, on the other hand, is not ideally suited to liquids, because the wide neck makes it easy for the liquid to slop out. For drinking, many people prefer to use bottles, because jars can slop their contents onto the consumer when he or she tries to take a sip.
Historically, bottles and jars were made from porcelain and glass. Many cultures have a rich tradition of ornamental containers, some of which can be seen on display in museums. Today, materials like plastic may be used as well, with plastic bottles and jars being less prone to breakage. Metal, wood, and natural materials like gourds can also be fashioned into bottles and jars.
Generally, a jar has a cylindrical shape with a mouth about the same diameter as the cylinder, and a bottle has a tapered neck leading to a mouth much smaller than the cylinder. Bottles and jars can have non-cylindrical shapes, but can still be distinguished by wide mouth verses narrow mouth.