A water bed consists of a heated, water-filled mattress inside either a "hard-sided" rectangular wooden frame or a "soft-sided" robust foam frame. Both types rely on a strong metal platform to bring the mattress to a convenient height. Early models had only one water chamber within the mattress, making it very bouncy, but later designs incorporated fiber blocks and several interconnected water chambers to reduce the wave action. Some modern water beds comprise a mixture of water and air chambers. Thermostatically controlled electrical heating pads usually maintain the water at body temperature, at around 86°F (30°C).
In 1883 Dr. William Hooper of Portsmouth, England, obtained a British patent for a water bed designed for patients at risk of developing bedsores. However, his model lacked the technologies to ensure that the beds were watertight, and he was unable to control the water temperature, so his invention was not a commercial success.
Charles Prior Hall (b. 1943) designed the modern water bed in 1968, when he was a student of design at San Francisco State University in California. He originally planned to design a chair, using a vinyl bag filled initially with liquid cornstarch and then jelly, but the resulting structure was not particularly comfortable with either filling. Hall then turned his attention to designing a water-filled bed. He was unable to obtain a patent for his design, though, because similar water beds had already been described in considerable detail in the science fiction novels of Robert A. Heinlein. However, Heinlein never attempted to construct his design.
