joule

just some handy conversions:
joule = 23.73042 x foot-poundal
joule = 684.9315 x lumen-second
joule (absolute) = 0.000948 x British Thermal unit
joule (absolute) = 9.43E-04 x British Thermal unit (39 F)
joule (absolute) = 9.48E-04 x British Thermal unit (60 F)
joule (absolute) = 0.23895 x calorie (gram) @ 15 C
joule (absolute) = 0.23918 x calorie (gram) @ 20 C
joule (absolute) = 0.23889 x calorie (gram; mean)
joule (absolute) = 0.000239 x calorie (kilogram; mean)
joule (absolute) = 3.78E-07 x cheval-vapeur heure
joule (absolute) = 9.869233 x cubic centimeter (atmosphere)
joule (absolute) = 0.000349 x cubic foot (atmosphere)
joule (absolute) = 10000000 x dyne-centimeter
joule (absolute) = 10000000 x erg
joule (absolute) = 0.73756 x foot-pound
joule (absolute) = 723.3 x foot-poundal
joule (absolute) = 10200 x gram-centimeter
joule (absolute) = 3.73E-07 x horsepower-hour
joule (absolute) = 0.99968 x joule (International)
joule (absolute) = 0.10197 x kilogram-meter
joule (absolute) = 2.78E-07 x kilowatt-hour
joule (absolute) = 0.009869 x liter (atmosphere)
joule (absolute) = 683.0601 x lumen-second
joule (absolute) = 1 x newton-meter
joule (absolute) = 0.000278 x watt-hour
joule (absolute) = 1 x watt-second
joule (International) = 1.00032 x joule (absolute)
joule per centimeter = 10000000 x dyne
joule per centimeter = 10200 x gram
joule per centimeter = 100 x joule per meter
joule per centimeter = 10.19716 x kilogram
joule per centimeter = 22.48 x pound
joule per centimeter = 723.3 x poundal
joule per meter = 100000 x dyne
joule per meter = 101.968 x gram
joule per meter = 0.01 x joule per centimeter
joule per meter = 0.101972 x kilogram
joule per meter = 0.22482 x pound
joule per meter = 7.23275 x poundal
joule per second = 1 x watt
joule per square meter = 2.39E-05 x langley


Bet you didn't know we had that many measurements, eh?
Sources: Chemistry 5th Ed. Textbook; TrapperKeeperNotes

Joule (commonly pronounced "jew'l") is the SI unit for energy or work in all forms, and it is one of the derived SI units. It is also the unit for quantity of heat, where it replaces the calorie whenever possible. The symbol for joule is J and the unit is defined as

the work done when the point of application of 1 MKS (meter, kilogram, second) unit of force (newton) moves a distance of one metre in the direction of the force

It is worth pointing out that 1 J = 1 Nm - which follows directly by the above definition - and the educated reader will immediately notice that newton meter (Nm) is the SI unit for torque. Torque and energy are however two different physical phenomena, which is why joule should be used only for energy, and newton meter should only be used for torque.

Furthermore, since the unit newton also is a derived SI unit, we can write

1 J = 1 Nm = 1 m² kg/s²

This makes possible another definition of the unit expressed only in the base SI units. Keeping in mind that kinetic energy is defined as

E_k = m v²/2

we now can define the energy unit joule directly as

the kinetic energy of two kilograms moving at a velocity of one meter per second

which is pretty much like a small cat walking at a steady pace.

The unit is named in honor of James Prescott Joule (pronounced "jowl"), a British physicist who in addition to formulating Joule's law also helped Robert Mayer and Hermann von Helmholtz in developing the principle of energy as being indestructible.

Joule (?), n. [From the distinguished English physicist, James P. Joule.] Physics.

A unit of work which is equal to 107 units of work in the C. G. S. system of units (ergs), and is practically equivalent to the energy expended in one second by an electric current of one ampere in a resistance of one ohm. One joule is approximately equal to 0.738 foot pounds.

Joule's equivalent. See under Equivalent, n.

 

© Webster 1913.