Overview
The name is derived from the general resemblance to a bowl used for food or liquids. In size, material and shape, bowls vary greatly, from one-hitters no larger in interior diameter (at the top) than a cigarette to commercial bowls the diameter of a nickel, which are widely promoted but tend to burn too hot when an impatient user sucks too hard. Usually the depth (before narrowing to a shaft) is a little less than the diameter. Often a fine metal screen is embedded inside, helping prevent drawing small particles down to clog the channel; this permits using finely sifted grades of herb or kief which vaporize out maximum cannabinoids. The material of construction is usually glass or metal, sometimes wood or clay. Bowls can be made of a different material than the device that they are attached to, such as a bong made of heat-sensitive materials like plastic that would melt or otherwise be ruined by direct contact with a heating source.
The bowl of a bong (water-pipe) is mounted on a slide or stem, depending upon the type. A stem is a singular piece that fits into a hole in the bong's chamber whereas a slide fits into a special attachment built into the bong. Some stems can be fixed or removable, while slides are always removable.
People have also been known to make homemade bowls out of numerous household items. Due to health risk it is not suggested to use aluminum foil, cans or bottles.
In Australia and New Zealand the 'bowl' is usually referred to as the 'cone' or 'conepiece'.
Read more about this topic: Bowl (smoking)