The History of
Cloud Physics
It has not been until very recently (since the 1940s) that significant advances have been made in cloud physics that have really begun to cement a solid understanding of key processes, but some of the groundwork was laid way back in the 17th century as scientific minds pondered the fundamental concepts. Otto von Guericke (1602-1686), a German physicist, came up with the idea that clouds were comprised of water bubbles, an idea that was later proven incorrect over a century later by Augustus Waller (1816-1870), whose observations were confirmed by Richard Assmann (1845-1918). However, Guericke had come up with the right idea that water and air are not the same substance in different forms, a concept that took analytical chemists until after 1760 to demonstrate.
In the 18th and 19th centuries, considerable effort was Image courtesy:
put into the analysis of individual cloud particles, but it Smithsonian Institute Libraries
took many years to come up with quantitative
explanations for their formation. It was P.J. Coulier (1824-1890) and John Aitken (1839-1919) who first demonstrated through the use of expansion chambers that dust particles in the atmosphere were necessary for the formation of water droplets from water vapor. This tied into earlier ideas on how clouds cultivate water drops which eventually fall to the ground as precipitation. James Hutton (1726-1797) theorized that precipitation is brought about by mixing humid air masses of different temperatures. This was only partially correct, as it ignored the physical consequences of converting water vapor to liquid. It was not until almost a century later that cooling by expansion of rising, humid air was shown to be the process that would give rise to enough condensed water in a cloud to produce amounts of precipitation that agreed with observations on the ground. This formulated the ideas of adiabatic cooling, which were set up by Benjamin Franklin's (1706-1790) observations that air heated by the sun would rise, creating a convective cell.
It has not been until very recently (since the 1940s) that significant advances have been made in cloud physics that have really begun to cement a solid understanding of key processes, but some of the groundwork was laid way back in the 17th century as scientific minds pondered the fundamental concepts. Otto von Guericke (1602-1686), a German physicist, came up with the idea that clouds were comprised of water bubbles, an idea that was later proven incorrect over a century later by Augustus Waller (1816-1870), whose observations were confirmed by Richard Assmann (1845-1918). However, Guericke had come up with the right idea that water and air are not the same substance in different forms, a concept that took analytical chemists until after 1760 to demonstrate.
In the 18th and 19th centuries, considerable effort was Image courtesy:
put into the analysis of individual cloud particles, but it Smithsonian Institute Libraries
took many years to come up with quantitative
explanations for their formation. It was P.J. Coulier (1824-1890) and John Aitken (1839-1919) who first demonstrated through the use of expansion chambers that dust particles in the atmosphere were necessary for the formation of water droplets from water vapor. This tied into earlier ideas on how clouds cultivate water drops which eventually fall to the ground as precipitation. James Hutton (1726-1797) theorized that precipitation is brought about by mixing humid air masses of different temperatures. This was only partially correct, as it ignored the physical consequences of converting water vapor to liquid. It was not until almost a century later that cooling by expansion of rising, humid air was shown to be the process that would give rise to enough condensed water in a cloud to produce amounts of precipitation that agreed with observations on the ground. This formulated the ideas of adiabatic cooling, which were set up by Benjamin Franklin's (1706-1790) observations that air heated by the sun would rise, creating a convective cell.