Atmosphere (unit) for the purposes of specifying the physical properties of substances, “"standard pressure"” should be precisely . A pressure of 1 atm can also be stated as: Scuba divers and others use the word "atmosphere" and "atm" in relation to pressures that are relative to mean atmospheric pressure at sea level (1.013 bar). For example, a partial pressure of oxygen is calibrated typically using air at sea level, so is expressed in units of atm. The old European unit technical atmosphere (at) is equal to 1 kilogram-force per square centimetre (kgf/cm), Pa. Atmosphere (unit) The standard atmosphere (symbol: atm) is a
Sixteen-bar blues Sixteen-bar blues The sixteen-bar blues can be a variation on the standard twelve-bar blues or on the less common eight-bar blues. Sixteen-bar blues is also used commonly in ragtime music. Most sixteen bar blues are adapted from a standard twelve-bar progression. The standard twelve-bar blues progression is where each cell in the table represents one measure (or "bar"), "I" represents the tonic chord, "IV" the subdominant chord, and "V" the dominant chord. Twelve-bar progressions are formed by applying one of several formulae, including the following. One adaptation extends the first section of tonic chords (bars 1–4) by doubling or repeating