A bong or water pipe is a device that is usually used for smoking herbs, typically Cannabis [1], tobacco, and much less frequently other substances such as methamphetamine. Because many countries have laws against owning drug paraphernalia a bong being sold openly is likely sold for tobacco use but this can vary according to location. Bongs are often used by students who are should be in lectures. During operation the user inhales through the device which causes smoke to fill a chamber; this smoke is usually first bubbled through water. The bong enables the operator to smoke in a manner very different to what is possible with a simple smoking pipe or joint (spliff). Most bongs are designed to either cool the smoke before it enters the operator's lungs, build up a large buffer of smoke which the user inhales quickly, or both. The word bong derives from the Thai word baung [2] (บ้อง) which refers to a cut off section of bamboo.

Bongs also vary greatly in their shape, materials, colors, and sizes. Commonly constructed from acrylic, ceramic, or glass, bongs can also be fabricated from materials as diverse as pykrete or even from household objects. Some people make bongs out of fruits and vegetables, discarding them once they start to decompose. Many bongs are regarded for their style, distinct vivid colors, or customizations such as stickers, and become a personalized signature of that particular bong owner.

Operation

Principles of operation

When using a bong, one inhales with his or her mouth sealed over an opening at the top. This reduces the air pressure in the chamber of the bong above the water level in the bottom of the bong. To equalize the pressure, the atmosphere pushes air through the combustible matter releasing smoke in the bowl travelling down the stem. The smoke then bubbles through the water, into the chamber and into the users' mouth and lungs. This bubbling action leads to a characteristic noise. For example, if you 'bubble' a glass of milk with a drinking straw, by placing the straw beneath the surface of the milk and blowing, you are demonstrating the same physics, except that you are assuming the role of the atmosphere and not the bong user.

Some bongs have a carburetor or carb, also called a shotty (from shotgun); choke; or rush (hole); a small hole or bleed valve that the user places his finger over when first inhaling allowing the chamber to fill up with smoke. When the user releases the carb while still inhaling, fresh air is allowed to rush in through the hole, "clearing" it of smoke. The fresh air forces the smoke into the users lungs more rapidly than just breathing will do. In other bongs, the bowl-piece is removable. This piece is then called a 'slide' or 'pull', and is similar to the carb in function. When the slide is removed, fresh air instead of smoke bubbles through, and acts to clear the chamber. An audio recording of a bong with a slide style carb being used is available (see media help).

Motivations for operation

The characteristics of the bong enable the material to be smoked in ways not possible with a simple pipe or spliff. Because the chamber on most bongs can be up to 6 inches (15 cm) in diameter the speed of the air moving through the chamber is reduced and the chamber now acts as a large buffer of smoke. Depending on the length of the bong a considerable amount of smoke can be built up in this way. On the larger bongs, about 4 ft (1.2 m) tall, the operator must stop drawing on the bong when the smoke reaches their lips. At this point the operator must exhale deeply, open the carb, and use the entire contents of their lungs to clear the chamber of the charge of smoke. This high concentration of smoke in the lungs enables the operator to transfer much higher quantities of the chemicals in the smoke into their lungs but also tends to waste large amounts of the smoke. The longer the operator can hold the hit in, the more chemicals he will extract from it, but this becomes more difficult as the smoke gets more dense and the quantity increases. Individuals in the Cannabis culture who can hold in a monster hit are typically held in high regard.

Bubbling the smoke through water also serves to cool down the smoke, which is typically very hot, and to trap some of the heavier and more water-soluble particulate matter, keeping it from entering the smoker's lungs. Most smokers believe that bongs are healthier than other smoking devices; however, a 2000 NORML-MAPS study found that "waterpipes filter out more psychoactive THC than they do other tars, thereby requiring users to smoke more to reach their desired effect"[3]. The analysis used smoke from NIDA-supplied marijuana drawn through a smoking machine adjusted to mimic the puff length of marijuana smokers. The apparatus, comparing smoke from a standard bong, a small portable device with a folding pipestem, a battery-operated model with a motorized paddle to thoroughly mix the smoke in the water, and two different types of vaporizers, found that the unfiltered joint outperformed all devices except the vaporizers, with a ratio of about 1 part cannabinoids to 13 parts tar.

Bong water

Used bong water is a notoriously disgusting fluid. In many movies and even in company of others stories are told of bong water's ability to stain anything and make it smell awful. Bong water ranges from clear when it is fresh, to a slightly used green, yellow or brown tint, which will get worse as the water is used more. A practice of some bong users is to turn the bowl around backwards and suck the remaining ash and unburned material down the stem into the water when the bowl is empty. While this is convenient it rapidly degrades the quality of the bong water. If this is done bong water can go from dark green or grey, to black, and will usually have chunks of dark unburned material floating around. As the quality of the water degrades so does the taste of the smoke. Over a long enough time the bong will develop a distinct unpleasant odor and the smoke drawn through it will acquire that taste as well. Bong water is extremely unpleasant to ingest. Drinking bong water will produce minimal psychoactive effect, since THC and other cannabinoids are minimally soluble in water. It is posible to use alcohol-based liquids as bong water. Even though THC and other cannabinoids are alcohol-soluble, such a small area of the smoke (i.e. the surface of the bubbles)comes into contact with the bong water that it is negligable. This includes using mouthwash, liquor, beer and anything else with alcohol.

Description

A typical bong is made of few components, as noted on the picture:

1. A mouthpiece, where the user's mouth is placed over, sealing out air through that hole. Thus the bong is airtight (providing there is also an airtight seal around the stem. If a "carb" is present, it must also be covered). When "airtight" it has but one small source of air, which comes into effect when the user inhales through the mouth piece. If all the smoke isn't removed from the bong in a single hit, the user can place their mouth again over the bong to again inhale, or hover their mouth closely over the bong to slowly inhale the smoke.
2. A chamber, where smoke collects. When enough smoke has accumulated it is finally inhaled. This is accelerated by using a "carb" or by removing the bowl, which allows air to enter the chamber when inhalation takes place. The height and width of the chamber can vary, this changes the volume.
3. A base, which holds the water, is usually wider than the chamber so it can stand-alone without tipping (see the consequences of a spillage.) The bottom of the "stem" sits in the water, on an angle. The opening at the bottom of the stem must be underwater to bubble the water. The water temperature will affect the temperature of the smoke inhaled (e.g. a bong with water and crushed ice as a filter will allow the user to inhale cooler smoke, providing a less harsh experience). Some bongs also have a removable, water-tight base, for easy changing of the bong water.
4. A stem (a.k.a. female piece) sits in the base and pokes out of the chamber at a degree higher than the water level. It holds the conepiece/bowl and enables smoke to pass through the water when in use. The stem collects "resin" over time which can clog the stem, and reduce the air flow through the water.
5. A bowl (sometimes called a conepiece or a male piece) is usually a removable cup or cone shaped container, where the cannabis is packed and ignited. In rare occasions the bowl is not removable. Made of metal, glass, or ceramic, a bowl can be joined to the stem, or can just sit in the stem. The bowl forms a seal around the stem so that the only inlet of air is through the bowl. Over time burnt residue will collect on parts of the bowl.

Additional parts

• A carb allows for an accelerated removal of smoke from the chamber. It is often a simple hole in the wall of the chamber(covered by a finger or removable seal). When smoke is inhaled through the mouthpiece and the carb is uncovered, air enters through the carb and pushes the present smoke out through the mouthpiece. This extra hole is not usually present in a bong with a removable bowl, as removing the bowl also allows more air to flow in to displace the smoke, eliminating the need for a carb.
• A second (or more) chamber(s) can be attached to a bong to multiply the filtration, for a smoother intake of smoke. Such an apparatus may be referred to as a "double bubbler".
• A diffuser is a down pipe/tube or down stem that has a capped end with small holes in it. This makes the smoke bubbles coming out of the downpipe and into the water smaller, and as a result, the filtration is more effective.
• An ice catcher, usually present as an indentation in the chamber, serves to hold ice in the chamber of the bong. This ice will further cool the smoke which some users find to be more pleasurable.

Materials

Since the bong is such a simple device it can be constructed out of nearly anything that is at least semi-rigid and can be made airtight. This includes, but is not limited to bamboo, plastic bottles, soda-pop cans, buckets, vases, beer bottles, hollow plastic and ceramic statues, chemistry beakers, snorkels, and many other common items. A clever bubbler can be constructed out of fruit such as apples and potatoes. The simplicity of bong construction has led people to consider constructing bongs with materials as outlandish as Pykrete. Most bongs purchased will be made out of glass (either hand blown or cast in molds) or clear acrylic tubing. Most of these bongs will include or otherwise utilize glass stems and bowls. However, cheaper bongs (nearly all made out of acrylic) may be designed with metal stems and bowls.

A common home-built bong is made from a bowl and stem purchased either from a head shop or fabricated from supplies around the house or from a hardware store; this could be out of tinfoil and a short length of garden hose for instance. The rest of the design needs nothing more than a knife or scissors, a 20 oz to 1 liter empty plastic bottle, and some duct tape. Just because a bong can be constructed this way does not indicate it is a good idea; to avoid dangerous fumes and chemicals all bowls and stems should be made of glass or metal.

Using materials such as PVC, plastic, rubber or garden hoses will emit toxic chemicals when heated. Aluminum foil releases toxic chemicals while heated, and its use should be avoided as high aluminum levels have been found in the brains of some patients with neurological diseases. Plastic can release fumes which may induce asthma. Little has been documented on the inhalation of these fumes but the practice should be avoided. Soda cans are widely used, but release aluminum fumes along with paint fumes when heated, which have been shown to cause brain damage. While duct tape may release rubber, metal and aluminum fumes, apples are toxin free.

Variety

Offshoots from the simple bong concept do exist. These devices either bubble the smoke through water to cool it or have very large chambers. Some of the devices are designed to allow slower and more controlled draw through the bowl which causes the smoke to be much denser.

Bubbler

A bubbler is a small bong that can be operated with only one hand (aside from having to provide an ignition source). In these devices the stem is internal and the bowl is at the very top. A majority of the bong is enclosed with only a hole in the side to act as the carb and the hole the smoke will exit on its way to the operator. These operate very much like a pipe since their internal chamber is so small but they have identical parts to a common bong. They are more pleasant to smoke out of than a regular pipe, becuase the smoke is cooled through the water.

Gravity bong