| 1.77 | measurand | ||
| Quantity intended to be measured. | |||
| Note 1: | The specification of a measurand requires knowledge of the kind of quantity, description of the state of the phenomenon, body, or substance embodying the quantity, including any relevant component, and the chemical entities involved. | ||
| Note 3: | The measurement, including the measuring system and the conditions under which the measurement is carried out, might change the phenomenon, body, or substance such that the quantity being measured may differ from the measurand as defined. In this case, adequate correction is necessary. | ||
| Example 1: | The electric potential difference between the terminals of a battery decreases when using a voltmeter with a significant internal conductance to perform the measurement. The open-circuit potential difference can be calculated from the internal resistances of the battery and the voltmeter. | ||
| Example 2: | The length of a steel rod in equilibrium with the ambient Celsius temperature of 23 °C will be different from the length at the specified temperature of 20 °C, which is the measurand. In this case, a correction may be applied. | ||
| Note 4: | In chemistry, analyte, or the name of a substance or compound, are terms sometimes used for ‘measurand’. This usage is erroneous because these terms do not refer to quantities. | ||
| Note 5: | The measurand may be operationally defined by reference to a documented measurement procedure to which only quantity values obtained by the same procedure can be compared.40 | ||
| Source: [VIM 2.3] with Note 2 omitted, minor clarification to Example 1, and added Note 5. | |||
| 1.77 | measurand | ||
| Quantity intended to be measured. | |||
| Note 1: | The specification of a measurand requires knowledge of the kind of quantity, description of the state of the phenomenon, body, or substance embodying the quantity, including any relevant component, and the chemical entities involved. | ||
| Note 3: | The measurement, including the measuring system and the conditions under which the measurement is carried out, might change the phenomenon, body, or substance such that the quantity being measured may differ from the measurand as defined. In this case, adequate correction is necessary. | ||
| Example 1: | The electric potential difference between the terminals of a battery decreases when using a voltmeter with a significant internal conductance to perform the measurement. The open-circuit potential difference can be calculated from the internal resistances of the battery and the voltmeter. | ||
| Example 2: | The length of a steel rod in equilibrium with the ambient Celsius temperature of 23 °C will be different from the length at the specified temperature of 20 °C, which is the measurand. In this case, a correction may be applied. | ||
| Note 4: | In chemistry, analyte, or the name of a substance or compound, are terms sometimes used for ‘measurand’. This usage is erroneous because these terms do not refer to quantities. | ||
| Note 5: | The measurand may be operationally defined by reference to a documented measurement procedure to which only quantity values obtained by the same procedure can be compared.40 | ||
| Source: [VIM 2.3] with Note 2 omitted, minor clarification to Example 1, and added Note 5. | |||