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The pitch drop experiment is a long-term experiment that measures the flow of a piece of pitch over many years. Pitch is the name for any of a number of highly viscous liquids that appear solid, most commonly bitumen. At room temperature, tar pitch flows at a very low rate, taking several years to form a single drop. == University of Queensland experiment == The best known version〔 of the experiment was started in 1927 by Professor Thomas Parnell of the University of Queensland in Brisbane, Australia, to demonstrate to students that some substances that appear to be solid are in fact very-high-viscosity fluids. Parnell poured a heated sample of pitch into a sealed funnel and allowed it to settle for three years. In 1930, the seal at the neck of the funnel was cut, allowing the pitch to start flowing. A glass dome covers the funnel and it is placed on display outside a lecture theatre. Large droplets form and fall over a period of about a decade. The eighth drop fell on 28 November 2000, allowing experimenters to calculate that the pitch has a viscosity approximately 230 billion (2.3) times that of water. This is recorded in Guinness World Records as the world's longest continuously running laboratory experiment, and it is expected that there is enough pitch in the funnel to allow it to continue for at least another hundred years. This experiment is predated by two other still-active scientific devices, the Oxford Electric Bell (1840) and the Beverly Clock (1864), but each of these has experienced brief interruptions since 1937. The experiment was not originally carried out under any special controlled atmospheric conditions, meaning that the viscosity could vary throughout the year with fluctuations in temperature. Some time after the seventh drop fell in 1988, air conditioning was added to the location where the experiment takes place. The lower average temperature has lengthened each drop's stretch before it separates from the rest of the pitch in the funnel. In October 2005, John Mainstone and the late Thomas Parnell were awarded the Ig Nobel Prize in Physics, a parody of the Nobel Prize, for the pitch drop experiment.〔(The 2005 Ig Nobel Prize Winners ). Improbable Research. Retrieved 6 July 2013.〕 Professor Mainstone subsequently commented: The experiment is monitored by a webcam〔http://www.theninthwatch.com/feed/〕 but technical problems prevented the November 2000 drop from being recorded.〔(University of Queensland page on the Pitch Drop experiment )〕 The pitch drop experiment is on public display on Level 2 of Parnell Building in the School of Mathematics and Physics at the St Lucia campus of the University of Queensland. Hundreds of thousands of Internet users check the live stream each year.〔 Professor John Mainstone died on 23 August 2013, aged 78, following a stroke.〔(【引用サイトリンク】url=http://www.nypost.com/p/news/international/professor_never_charge_event_famous_AKmMGqJi1lfJ0J3xbxW8fJ?utm_source=SFnewyorkpost&utm_medium=SFnewyorkpost )〕 The ninth drop touched the eighth drop on 17 April 2014.〔(【引用サイトリンク】 title=Pitch drop touches down – oh so gently )〕 However, it was still attached to the funnel. On 24 April 2014, Pitch Drop custodian Andrew White decided to replace the beaker holding the previous eight drops before the ninth drop fused to them. While the bell jar was being lifted, the wooden base wobbled and the ninth drop snapped away from the funnel. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「pitch drop experiment」の詳細全文を読む スポンサード リンク
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