William Thomson Lord Kelvin
1824 - 1907
Unit and Symbol: kelvin (K)
Quantity Measured: Thermodynamic Temperature
Definition: The kelvin is used to measure temperature based on the absolute scale. It is the SI unit of thermodynamic temperature. One kelvin (1 K) is defined as 1/273.16 (3.6609 x 10
-3) of the thermodynamic temperature of the triple point of pure water H
2O.
Significance: British mathematical physicist and engineer Lord Kelvin, the namesake of this unit, wrote a paper in 1848 on the need for a scale wherein the null point would be 'absolute zero', and the increment of temperature would be measured in degree Celsius. Lord Kelvin also calculated the value of absolute zero to be -273°C.
Blaise Pascal
1623 - 1662
Unit and Symbol: pascal (Pa)
Quantity Measured: Pressure
Definition: The pascal is defined as one newton per squared meter (1N/m
2). It is the SI derived unit for the measurement of pressure, internal pressure, stress, Young's modulus, and ultimate tensile strength.
Significance: Blaise Pascal, a French mathematician, physicist, inventor, writer, and Christian philosopher, made important contributions in the field of fluid mechanics, especially the concepts of pressure and vacuum. The unit of pressure has been named pascal in his honor.