clay, ceramic, corncob, glass, meerschaum, metal, gourd, stone, wood, bog oak and various combinations thereof, most notably, the classic English calabash pipe. The size of a pipe, particularly the bowl, depends largely on what is intended to be smoked in it. Large western-style tobacco pipes are used for strong-tasting, harsh tobaccos, the smoke from which is usually not inhaled. Smaller pipes such as the midwakh or kiseru are used to inhale milder tobaccos such as dokha and kizami or other substances such as cannabis and opium. Water pipes Water pipes bubble smoke through water to cool and wash the smoke. The two basic types are stationary hookahs, with one or more long flexible drawtubes, and portable bongs. Spoon pipes Spoon pipes (glass pipes or glass bowl pipes) have become increasingly common with the rise of cannabis or other narcotics smoking. Spoon pipes are normally made of borosilicate glass to withstand repeated exposure to high temperatures. They consist of a bowl for packing material into, stem for inhaling, and a carbureter (carb) for controlling suction and airflow into the pipe. These pipes utilize a two step process. First, the user inhales while lighting the smoking material and holding down the carb, allowing smoke to fill the stem. Then, the user releases the carb while inhaling to allow air to enter the stem and smoke to be pulled into the user's mouth. Health effects The overall health risks are 10% higher in pipe smokers than in non-smokers. However, pipe or cigar smokers who are former-cigarette smokers might retain a habit of smoke inhalation. In such cases, there is a 30% increase in the risk of heart disease and a nearly three times greater risk of developing COPD. In addition, there is a causal relationship between pipe smoking and mortality due to lung and other cancers, as well as periodontal problems, such as tooth and bone loss. However, all tobacco products deliver nicotine to the central nervous system, and there is a confirmed risk of dependence. Many forms of tobacco use are associated with a significantly increased risk of morbidity and premature mortality due to tobacco-related diseases. Culture The customs, vocabulary and etiquette that surround pipe smoking culture vary across the world and depend both on the people who are smoking and the substance being smoked. For example, in many places in Europe and North America, tobacco pipe smoking has sometimes been seen