A bath, bathtub (AmE), or tub (informal) is a large container for holding water in which a person may bathe (take a bath). Most modern bathtubs are made of acrylic or fiberglass, but alternatives are available in enamel over steel or cast iron, and occasionally waterproof finished wood. A bathtub is usually placed in a bathroom either as a stand-alone fixture or in conjunction with a shower. Modern bathtubs have overflow and waste drains and may have taps mounted on them. They may be built-in or free standing or sometimes sunken. Until recently, most bathtubs were roughly rectangular in shape but with the advent of acrylic thermoformed baths, more shapes are becoming available. Bathtubs are commonly white in colour although many other colours can be found. The process for enamelling cast iron bathtubs was invented by the Scottish-born American David Dunbar Buick. Two main styles of bathtub are common: Western-style bathtubs in which the bather lies down. These baths are typically shallow and long. Eastern style bathtubs in which the bather stands up. These are known as ofuro in Japan and are typically short and deep. Clawfoot tub: The clawfoot tub or claw-foot tub was considered a luxury item in the late 19th century, originally made from cast iron and lined with porcelain. Modern technology has contributed to a drop in the price of clawfoot tubs, which may now be made of fiberglass, acrylic or other modern materials. Clawfoot tubs usually require more water than a standard bathtub. While true antique clawfoot tubs are still considered collectible items, new reproduction clawfoot tubs are chosen by remodellers and new home builders and much like the Western-style bathtubs clawfoot tubs can also sometimes include showers. Clawfoot tubs come in 5 major styles: Classic Roll Rim, Roll Top, or Flat Rim tubs as seen in the picture above. Slipper tubs - where one end is raised and sloped creating a more comfortable lounging position. Double Slipper Tubs - where both ends are raised and sloped. Double Ended Tubs - where both ends of the tub are rounded. Notice how one end of the classic tub is rounded and one is fairly flat. Pedestal Tub - Pedestal tubs, unlike all the styles listed above, do not have claw feet. The tub rests on a pedestal in what most would term an art deco style. Evidence of pedestal tubs dates back to the Isle of Crete in 1000 BC. Baby bathtub: A baby bathtub is one used for bathing infants, especially those not yet old enough to sit up on their own. These can be either a small, stand-alone bath that is filled with water from another source, or a device for supporting the baby that is placed in a standard bathtub. Both types are designed to allow the baby to recline while keeping its head out of the water. Hot tubs: Hot tubs are common heated pools used for relaxation and sometimes for therapy. The "hippie" era (1950–1970) popularized them in America in songs and movies. Whirlpool tubs: Whirlpool tubs first became popular in America during the 1960s and 70s. A spa or hot tub is also called a "jacuzzi" since the word became a generic after plumbing component manufacturer Jacuzzi introduced the "Spa Whirlpool" in 1968. Air bubbles may be introduced into the nozzles via an air-bleed venturi pump.
Source:
http://en.wikipedia.org/wiki/Bathtub