<P> Although these units relate to the metric system , all of them have been considered obsolete in science since the adoption of the SI system . The unit of energy in the International System of Units is the joule . One small calorie is approximately 4.2 joules ( so one large calorie is about 4.2 kilojoules ) . The factor used to convert calories to joules at a given temperature is numerically equivalent to the specific heat capacity of water expressed in joules per kelvin per gram ( or per kilogram , for kilocalories ) . The precise conversion factor depends on the definition adopted . </P>
<P> Although these units relate to the metric system , all of them have been considered obsolete in science since the adoption of the SI system . The unit of energy in the International System of Units is the joule . One small calorie is approximately 4.2 joules ( so one large calorie is about 4.2 kilojoules ) . The factor used to convert calories to joules at a given temperature is numerically equivalent to the specific heat capacity of water expressed in joules per kelvin per gram ( or per kilogram , for kilocalories ) . The precise conversion factor depends on the definition adopted . </P>
how many joules is equal to one calorie
how many joules is equal to one calorie
approximately 4.2
approximately 4.2