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First mercury-in-glass thermometer
Daniel Gabriel Fahrenheit (1686–1736) designs a mercury-in-glass thermometer and develops a temperature scale now named after him. The three calibration points used are a freezing mixture of ice/salt (0°F), a water/ice mixture (32°F) and human body temperature (96°F) -
Dalton’s Law
John Dalton’s (1776–1844) He is the first to observe that the pressure of a mixture of gases is the sum of the pressures of the various gases in the mixture. Dalton’s Law takes the form PT=P1+P2+P3+... -
Graham’s Law
Thomas Graham (1805–1869) studies the way gases mix by diffusion as well as how they effuse through a semi-permeable barrier. He was able to show that the rate of effusion is inversely proportional to the square root of the molecular mass of the gas. -
Kinetic-molecular theory
Rudolf Clausius (1822–1888) He introduces the concept of mean free path and links temperature to gas particle speed. Physical properties of gases can now be explained in particle terms. -
Equation of state
Johannes van der Waals (1837–1923) realises gas laws and kinetic-molecular theory are based on an idealised gas. He develops an equation based on real gas behaviour that takes account of attractive forces between gas particles and the volume occupied by each particle.
