[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.76,0:00:11.23,Default,,0000,0000,0000,,Aristotle famously said,\N"Nature fears of empty space"
Dialogue: 0,0:00:11.23,0:00:16.02,Default,,0000,0000,0000,,when he claimed that a true vacuum, \Na space devoid of matter, could not exist
Dialogue: 0,0:00:16.02,0:00:19.10,Default,,0000,0000,0000,,because the surrounding matter\Nwould immediately fill it.
Dialogue: 0,0:00:19.10,0:00:21.99,Default,,0000,0000,0000,,Fortunately, he turned out to be wrong.
Dialogue: 0,0:00:21.99,0:00:25.01,Default,,0000,0000,0000,,A vacuum is a key component\Nof the barometer,
Dialogue: 0,0:00:25.01,0:00:27.49,Default,,0000,0000,0000,,an instrument for measuring air pressure.
Dialogue: 0,0:00:27.49,0:00:30.11,Default,,0000,0000,0000,,And because air pressure \Ncorrelates to temperature
Dialogue: 0,0:00:30.11,0:00:32.03,Default,,0000,0000,0000,,and rapid shifts in it can contribute to
Dialogue: 0,0:00:32.03,0:00:35.64,Default,,0000,0000,0000,,hurricanes, tornadoes \Nand other extreme weather events,
Dialogue: 0,0:00:35.64,0:00:38.16,Default,,0000,0000,0000,,a barometer is one of the\Nmost essential tools \N
Dialogue: 0,0:00:38.16,0:00:41.84,Default,,0000,0000,0000,,for weather forecasters and scientists alike.
Dialogue: 0,0:00:41.84,0:00:44.77,Default,,0000,0000,0000,,How does a barometer work,\Nand how was it invented?
Dialogue: 0,0:00:44.77,0:00:46.45,Default,,0000,0000,0000,,Well, it took awhile.
Dialogue: 0,0:00:46.45,0:00:49.74,Default,,0000,0000,0000,,Because the theory of Aristotle \Nand other ancient philosophers
Dialogue: 0,0:00:49.74,0:00:54.99,Default,,0000,0000,0000,,regarding the impossibility of a vacuum\Nseemed to hold true in everyday life,
Dialogue: 0,0:00:54.99,0:00:59.04,Default,,0000,0000,0000,,few seriously thought to question it\Nfor nearly 2,000 years --
Dialogue: 0,0:00:59.04,0:01:01.54,Default,,0000,0000,0000,,until necessity raised the issue.
Dialogue: 0,0:01:01.54,0:01:05.55,Default,,0000,0000,0000,,In the early 17th century,\NItalian miners faced a serious problem
Dialogue: 0,0:01:05.55,0:01:08.44,Default,,0000,0000,0000,,when they found that their pumps\Ncould not raise water \N
Dialogue: 0,0:01:08.44,0:01:10.82,Default,,0000,0000,0000,,more than 10.3 meters high.
Dialogue: 0,0:01:10.82,0:01:14.88,Default,,0000,0000,0000,,Some scientists at the time,\Nincluding one Galileo Galilei,
Dialogue: 0,0:01:14.88,0:01:20.31,Default,,0000,0000,0000,,proposed that sucking air out of the pipe\Nwas what made water rise to replace the void.
Dialogue: 0,0:01:20.31,0:01:25.61,Default,,0000,0000,0000,,But that its force was limited and could lift\Nno more than 10.3 meters of water.
Dialogue: 0,0:01:25.61,0:01:28.52,Default,,0000,0000,0000,,However, the idea of a \Nvacuum existing at all
Dialogue: 0,0:01:28.52,0:01:30.73,Default,,0000,0000,0000,,was still considered controversial.
Dialogue: 0,0:01:30.73,0:01:33.65,Default,,0000,0000,0000,,And the excitement over \NGalileo's unorthodox theory,
Dialogue: 0,0:01:33.65,0:01:38.23,Default,,0000,0000,0000,,led Gasparo Berti to conduct a simple\Nbut brilliant experiment
Dialogue: 0,0:01:38.23,0:01:40.21,Default,,0000,0000,0000,,to demonstrate that it was possible.
Dialogue: 0,0:01:40.21,0:01:42.40,Default,,0000,0000,0000,,A long tube was filled with water\N
Dialogue: 0,0:01:42.40,0:01:46.32,Default,,0000,0000,0000,,and placed standing in a shallow pool \Nwith both ends plugged.
Dialogue: 0,0:01:46.32,0:01:48.95,Default,,0000,0000,0000,,The bottom end of the tube \Nwas then opened
Dialogue: 0,0:01:48.95,0:01:51.43,Default,,0000,0000,0000,,and water poured out into the basin
Dialogue: 0,0:01:51.43,0:01:56.10,Default,,0000,0000,0000,,until the level of the water remaining \Nin the tube was 10.3 meters.
Dialogue: 0,0:01:56.10,0:02:00.02,Default,,0000,0000,0000,,With a gap remaining at the top,\Nand no air having entered the tube,
Dialogue: 0,0:02:00.02,0:02:04.40,Default,,0000,0000,0000,,Berti had succeeded in\Ndirectly creating a stable vacuum.
Dialogue: 0,0:02:04.40,0:02:08.50,Default,,0000,0000,0000,,But even though the possibility \Nof a vacuum had been demonstrated,
Dialogue: 0,0:02:08.50,0:02:11.41,Default,,0000,0000,0000,,not everyone was satisfied \Nwith Galileo's idea
Dialogue: 0,0:02:11.41,0:02:14.46,Default,,0000,0000,0000,,that this empty void \Nwas exerting some mysterious
Dialogue: 0,0:02:14.46,0:02:16.94,Default,,0000,0000,0000,,yet finite force on the water.
Dialogue: 0,0:02:16.94,0:02:20.97,Default,,0000,0000,0000,,Evangelista Torricelli, \NGalileo's young pupil and friend,\N
Dialogue: 0,0:02:20.97,0:02:23.68,Default,,0000,0000,0000,,decided to look at the problem\Nfrom a different angle.
Dialogue: 0,0:02:23.68,0:02:27.02,Default,,0000,0000,0000,,Instead of focusing on the \Nempty space inside the tube,
Dialogue: 0,0:02:27.02,0:02:30.39,Default,,0000,0000,0000,,he asked himself,\N"What else could be influencing the water?"
Dialogue: 0,0:02:30.39,0:02:34.33,Default,,0000,0000,0000,,Because the only thing in contact \Nwith the water was the air surrounding the pool,
Dialogue: 0,0:02:34.33,0:02:38.16,Default,,0000,0000,0000,,he believed the pressure from this air\Ncould be the only thing preventing
Dialogue: 0,0:02:38.16,0:02:41.25,Default,,0000,0000,0000,,the water level in the tube\Nfrom dropping further.
Dialogue: 0,0:02:41.25,0:02:45.15,Default,,0000,0000,0000,,He realized that the experiment \Nwas not only a tool to create a vacuum,
Dialogue: 0,0:02:45.15,0:02:47.29,Default,,0000,0000,0000,,but operated as a balance
Dialogue: 0,0:02:47.29,0:02:50.68,Default,,0000,0000,0000,,between the atmospheric pressure\Non the water outside the tube
Dialogue: 0,0:02:50.68,0:02:53.90,Default,,0000,0000,0000,,and the pressure from the\Nwater column inside the tube.
Dialogue: 0,0:02:53.90,0:02:58.53,Default,,0000,0000,0000,,The water level in the tube decreases\Nuntil the two pressures are equal,
Dialogue: 0,0:02:58.53,0:03:02.34,Default,,0000,0000,0000,,which just happens to be\Nwhen the water is at 10.3 meters.
Dialogue: 0,0:03:02.34,0:03:04.66,Default,,0000,0000,0000,,This idea was not easily accepted,
Dialogue: 0,0:03:04.66,0:03:07.55,Default,,0000,0000,0000,,as Galileo and others \Nhad traditionally thought
Dialogue: 0,0:03:07.55,0:03:12.06,Default,,0000,0000,0000,,that atmospheric air has no weight\Nand exerts no pressure.
Dialogue: 0,0:03:12.06,0:03:14.90,Default,,0000,0000,0000,,Torricelli decided to \Nrepeat Berti's experiment\N
Dialogue: 0,0:03:14.90,0:03:16.85,Default,,0000,0000,0000,,with mercury instead of water.
Dialogue: 0,0:03:16.85,0:03:20.17,Default,,0000,0000,0000,,Because mercury was denser, \Nit fell farther than the water
Dialogue: 0,0:03:20.17,0:03:23.99,Default,,0000,0000,0000,,and the mercury column stood\Nonly about 76 centimeters tall.
Dialogue: 0,0:03:23.99,0:03:28.24,Default,,0000,0000,0000,,Not only did this allow Torricelli to make\Nthe instrument much more compact,
Dialogue: 0,0:03:28.24,0:03:32.34,Default,,0000,0000,0000,,it supported his idea that weight\Nwas the deciding factor.
Dialogue: 0,0:03:32.34,0:03:37.89,Default,,0000,0000,0000,,A variation on the experiment used two tubes\Nwith one having a large bubble at the top.
Dialogue: 0,0:03:37.89,0:03:42.14,Default,,0000,0000,0000,,If Galileo's interpretation had been correct,\Nthe bigger vacuum in the second tube
Dialogue: 0,0:03:42.14,0:03:45.80,Default,,0000,0000,0000,,should have exerted more suction\Nand lifted the mercury higher.
Dialogue: 0,0:03:45.80,0:03:48.84,Default,,0000,0000,0000,,But the level in both tubes was the same.
Dialogue: 0,0:03:48.84,0:03:53.08,Default,,0000,0000,0000,,The ultimate support for Torricelli's theory\Ncame via Blaise Pascal
Dialogue: 0,0:03:53.08,0:03:56.31,Default,,0000,0000,0000,,who had such a mercury tube\Ntaken up a mountain
Dialogue: 0,0:03:56.31,0:03:58.28,Default,,0000,0000,0000,,and showed that the mercury level dropped
Dialogue: 0,0:03:58.28,0:04:02.03,Default,,0000,0000,0000,,as the atmospheric pressure\Ndecreased with altitude.
Dialogue: 0,0:04:02.03,0:04:05.45,Default,,0000,0000,0000,,Mercury barometers based on \NTorricelli's original model
Dialogue: 0,0:04:05.45,0:04:10.37,Default,,0000,0000,0000,,remained one of the most common ways\Nto measure atmospheric pressure until 2007
Dialogue: 0,0:04:10.37,0:04:13.62,Default,,0000,0000,0000,,when restrictions on the use of\Nmercury due to its toxicity
Dialogue: 0,0:04:13.62,0:04:16.85,Default,,0000,0000,0000,,led to them no longer\Nbeing produced in Europe.
Dialogue: 0,0:04:16.85,0:04:18.93,Default,,0000,0000,0000,,Nevertheless, Torricelli's invention,\N
Dialogue: 0,0:04:18.93,0:04:22.08,Default,,0000,0000,0000,,born of the willingness to question\Nlong accepted dogmas
Dialogue: 0,0:04:22.08,0:04:25.80,Default,,0000,0000,0000,,about vacuums and the weight of air,\Nis an outstanding example
Dialogue: 0,0:04:25.80,0:04:29.08,Default,,0000,0000,0000,,of how thinking outside of the box\N-- or the tube --
Dialogue: 0,0:04:29.08,0:04:30.59,Default,,0000,0000,0000,,can have a heavy impact.