Editing Pitch drop experiment (section)

{{Short description|Long-term experiment measuring the flow of pitch}}
{{Distinguish|oil drop experiment}}
{{Use Australian English|date=June 2020}}
{{Use dmy dates|date=September 2020}}
[[Image:University of Queensland Pitch drop experiment-white bg.jpg|thumb|right|upright|The [[University of Queensland]] pitch drop experiment, demonstrating the [[viscosity]] of [[bitumen]].]]
A '''pitch drop experiment''' is a [[long-term experiment]] which measures the flow of a piece of [[Pitch (resin)|pitch]] over many years. "Pitch" is the name for any of a number of highly [[Viscosity|viscous]] liquids which appear solid, most commonly [[bitumen]], also known as asphalt. At room temperature, tar pitch flows at a very low rate, taking several years to form a single drop.