A water pipe is a device that filters smoke before it is inhaled, clearing it of impurities. Although many people strongly associate water pipes with illegal drugs, they are commonly used to smoke tobacco and other legal substances. You can usually tell somebody’s intentions by how they refer to their water pipe in private: if they have a “hookah” or a “water pipe,” they will probably be smoking tobacco, perhaps flavored. However, if they refer to their “piece” or a “bong,” it’s a good bet that they will be smoking something illegal. I cannot recommend the use of illegal drugs, so please, use this information for something legal. Let’s assume for the duration of this writeup that we will be smoking harmless tobacco.
The basic concept behind a water pipe is that many of the impurities and toxic chemicals in smokable substances are water-soluble, while the chemical that the smoker is most interested in is not. This works for, say, nicotine and delta-9-THC, but is not a universal guarantee.
Most water pipes have a central reservoir full of water, with two pipes connected to it: one which has an opening below the water level of the reservoir, and the other which does not. The pipe that empties below the water level has the tobacco placed in it. Here’s a picture:
\ \ __| |__
\ \_/ | | \
\ | | \
| 3 | | |
| |4| |
Now, imagine that you press your lips around the opening (1), forming a seal. By inhaling, you will begin to form a partial vacuum within the central chamber (3). Physics being what they are, the pipe will attempt to equalize the internal pressure by drawing air through the other pipe. If you light the tobacco (2), a strong air current will be pulled through it, with the dual effect of quickly burning the tobacco and drawing the resulting smoke down into the reservoir.
Because the pipe with the tobacco in it has its other opening below the water level (4), the smoke will necessarily have to enter through the water, then bubble out of it, in order to equalize the air pressure. Elementary chemistry tells us that the water-soluble chemicals in the smoke will begin to dissolve into the water. The chamber will begin to fill with smoke. Although the smoker will begin to inhale some smoke at this point, the real point of the water pipe is that making a clean opening into the chamber, whether through a carburetor or by removing the top of the tobacco pipe, exposing it to the air, will allow the smoker to inhale the entire contents of the chamber, which will most likely be quite dense at this point.
Smoke filtered in this way will feel much smoother to a smoker used to unfiltered smoke, as many of the harmful chemicals in smoke are water-soluble. However, because, as I mentioned, the smoke in the chamber is usually pretty dense, it will be a significantly larger amount of smoke than most people are used to inhaling. This can be overwhelming to people unused to the strength of a water pipe.
Eventually, the water will need to be cleaned out. Keep in mind that this water is going to be full of all of the stuff that you didn’t want to have in your lungs in the first place; the water will be toxic, foul-smelling, and in other ways unpleasant. Don’t spill it on anything you care about, unless you want that object, person, or animal to smell disgusting for a long, long time.
Other variations on the design make it unnecessary to let air into the chamber in order to get the smoke out: many hookahs have several hoses connected to the chamber instead of the second pipe, and do not require the chamber to be “cleared” in order to get a dose of smoke. Although many water pipes are large, smaller ones, the size of standard pipes, are readily available.
As I mentioned above, because “water pipe” is a generic term for these devices, and “bong” usually refers specifically to devices used illegally, most stores that sell water pipes will have no qualms about kicking out customers who ask for bongs. A store has no good reason to seem to be condoning drug use, as the legal repercussions for selling drug paraphernalia are usually hefty.
And make no mistake: it is dangerous to own a water pipe. Even if you use it legitimately, many common illegal drugs (including cannabis, crack cocaine, and methamphetamines) can be successfully smoked through a water pipe. Police may assume that your water pipe is used illegally until it can be verified in a lab; many universities have a policy that any water pipe is considered paraphernalia. If you are worried, you may find it safer to own a smaller water pipe, or not own one at all.