How does math guide our ships at sea? - George Christoph

422,893 views ใƒป 2012-10-11

TED-Ed


ืื ื ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ืœืžื˜ื” ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ.

00:00
Transcriber: tom carter Reviewer: Bedirhan Cinar
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ืชืจื’ื•ื: eviatar edlerman ืขืจื™ื›ื”: Ido Dekkers
00:15
As you can imagine, 400 years ago,
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ื›ืžื• ืฉืืชื ื™ื›ื•ืœื™ื ืœื“ืžื™ื™ืŸ, ืœืคื ื™ 400 ืฉื ื”
00:19
navigating the open ocean was difficult.
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ื ื™ื•ื•ื˜ ื‘ืื•ืงื™ื™ื ื•ืก ื”ื™ื” ืงืฉื”.
00:21
The winds and currents pushed and pulled ships off course,
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ื”ืจื•ื—ื•ืช ื•ื”ื–ืจืžื™ื ื“ื—ืคื• ื•ืžืฉื›ื• ืืช ื”ืกืคื™ื ื” ื”ืจื—ืง ืžื”ืžืกืœื•ืœ,
00:25
and so sailors based their directions on the port they left,
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ื•ืœื›ืŸ ืžืœื—ื™ื ื‘ื™ืกืกื• ืืช ื”ื›ื™ื•ื•ืŸ ืฉืœื”ื ืขืœ ืคื™ ื”ื ืžืœ ืžืžื ื• ื”ื ื™ืฆืื•,
00:29
attempting to maintain an accurate record of the ship's direction and the distance sailed.
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ืชื•ืš ื ืกื™ื•ืŸ ืœืฉืžื•ืจ ืขืœ ืจื™ืฉื•ื ืžื“ื•ื™ืง ืฉืœ ื›ื™ื•ื•ืŸ ื•ื”ืžืจื—ืง ืฉื”ืกืคื™ื ื” ื”ืคืœื™ื’ื”.
00:35
This process was known as dead reckoning,
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ื”ืชื”ืœื™ืš ื”ื–ื” ื ืงืจื ื ื™ื•ื•ื˜ ืžื ืงื•ื“ื” ืœื ืงื•ื“ื”,
00:38
because being just half a degree off could result in sailing right past the island that lay several miles just over the horizon.
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ืžื›ื™ื•ื•ืŸ ืฉืกื˜ื™ื™ื” ืงื˜ื ื” ืฉืœ ื—ืฆื™ ืžืขืœื” ื™ื›ื•ืœื” ืœื’ืจื•ื ืœืคืกืคื•ืก ืฉืœ ืื™ ืฉื ืžืฆื ื›ืžื” ืง"ืž ืžืขื‘ืจ ืœืื•ืคืง.
00:46
This was an easy mistake to make.
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ื–ืืช ื˜ืขื•ืช ืฉืงืœ ืœืขืฉื•ืช.
00:49
Thankfully, three inventions made modern navigation possible:
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ืœืžืจื‘ื” ื”ืžื–ืœ, ืฉืœื•ืฉ ื”ืžืฆืื•ืช ืื™ืคืฉืจื• ืืช ื”ื ื™ื•ื•ื˜ ื”ืžื•ื“ืจื ื™:
00:53
sextants, clocks and the mathematics necessary to perform the required calculations quickly and easily.
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ืกืงืกื˜ื ื˜, ืฉืขื•ื ื™ื ื•ื”ืžืชืžื˜ื™ืงื” ื”ื“ืจื•ืฉื” ืœื‘ื™ืฆื•ืข ื”ื—ื™ืฉื•ื‘ื™ื ื”ื“ืจื•ืฉื™ื ื‘ืงืœื•ืช ื•ื‘ืžื”ื™ืจื•ืช.
01:00
All are important. Without the right tools, many sailors would be reluctant to sail too far from the sight of land.
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ื›ื•ืœื ื—ืฉื•ื‘ื™ื. ื‘ืœื™ ื”ื›ืœื™ื ื”ื“ืจื•ืฉื™ื, ืžืœื—ื™ื ืจื‘ื™ื ื”ื™ื• ืžื”ืกืกื™ื ืœื”ืชืจื—ืง ืžื ืžืœ ืžื‘ื˜ื—ื™ื.
01:08
John Bird, an instrument maker in London,
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ื’'ื•ืŸ ื‘ื™ืจื“, ื™ื•ืฆืจ ืžื›ืฉื™ืจื™ื ืžืœื•ื ื“ื•ืŸ,
01:11
made the first device that could measure the angle between the sun and the horizon during the day,
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ื™ื™ืฆืจ ืืช ื”ืžื›ืฉื™ืจ ื”ืจืืฉื•ืŸ ืฉืžื“ื“ ืืช ื”ื–ื•ื™ืช ื‘ื™ืŸ ื”ืฉืžืฉ ื•ื”ืื•ืคืง ื‘ืžื”ืœืš ื”ื™ื•ื,
01:16
called a sextant.
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ื”ืžื›ืฉื™ืจ ื ืงืจื ืกืงืกื˜ื ื˜.
01:19
Knowing this angle was important, because it could be compared to the angle back in England at the exact same time.
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ื™ื“ื™ืขืช ื”ื–ื•ื•ื™ืช ื”ื–ืืช ื”ื™ืชื” ื—ืฉื•ื‘ื” ืžื›ื™ื•ื•ืŸ ืฉื ื™ืชืŸ ื”ื™ื” ืœื”ืฉื•ื•ืช ืื•ืชื” ืœืื•ืชื” ื”ื–ื•ื™ื™ืช ืฉื ืžื“ื“ื” ื‘ืื•ืชื• ื”ื–ืžืŸ ื‘ืื ื’ืœื™ื”.
01:26
Comparing these two angles was necessary to determine the longitude of the ship.
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ื”ืฉื•ื•ืื” ื‘ื™ืŸ ืฉืชื™ ื–ื•ื•ื™ืช ืืœื” ื”ื™ืชื” ื”ื›ืจื—ื™ืช ืœืงื‘ื™ืขืช ืงื• ื”ืื•ืจืš ืฉื‘ื• ื ืžืฆืืช ื”ืกืคื™ื ื”.
01:31
Clocks came next.
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ืฉืขื•ื ื™ื ื‘ืื• ืื—"ื›
01:33
In 1761, John Harrison, an English clockmaker and carpenter,
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ื‘ืฉื ืช 1761, ื’'ื•ืŸ ื”ืจื™ืกื•ืŸ, ื™ื•ืฆืจ ืฉืขื•ื ื™ื ื•ื ื’ืจ,
01:38
built a clock that could keep accurate time at sea.
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ื‘ื ื” ืฉืขื•ืŸ ืฉื ืชืŸ ืฉืขื” ืžื“ื•ื™ืงืช ื‘ื™ื.
01:41
The timepiece that could maintain accurate time while on a pitching, yawing deck in harsh conditions
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ื”ืฉืขื•ืŸ ืฉื”ื™ื” ืฆืจื™ืš ืœืชืช ืฉืขื” ืžื“ื•ื™ืงืช ื’ื ื‘ืžื”ืœืš ื”ื ื“ื ื•ื“ ื•ื”ืกื‘ืกื•ื‘ ืฉืœ ื”ืกื™ืคื•ืŸ ื‘ืชื ืื™ ื™ื ืงืฉื™ื
01:48
was necessary in order to know the time back in England.
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ื”ื™ื” ื”ื›ืจื—ื™ ื‘ื›ื“ื™ ืœื“ืขืช ืืช ื”ืฉืขื” ื‘ืื ื’ืœื™ื”.
01:52
There was one catch though:
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ื”ื™ื” ืžืœื›ื•ื“ ืื—ื“ ื‘ืขื ื™ื™ืŸ:
01:54
since such a timepiece was handmade, it was very expensive.
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ืžื›ื™ื•ื•ืŸ ืฉื›ืœ ืฉืขื•ืŸ ื›ื–ื” ื ื‘ื ื” ื‘ื™ื“, ื”ื•ื ื”ื™ื” ื™ืงืจ ืžืื“.
01:58
So an alternate method using lunar measurements and intense calculations was often used to cut costs.
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ืฉื™ื˜ื” ื—ืœื•ืคื™ืช ืฉื‘ื” ืžืฉืชืžืฉื™ื ื‘ืžื“ื™ื“ื•ืช ื”ื™ืจื— ื•ื—ื™ืฉื•ื‘ื™ื ืืจื•ื›ื™ื ื”ื™ืชื” ื‘ืฉื™ืžื•ืฉ ื‘ืื•ืคืŸ ืฉื›ื™ื— ื‘ื›ื“ื™ ืœื”ื•ืจื™ื“ ืขืœื•ื™ื•ืช.
02:05
The calculations to determine a ship's location for each measurement could take hours.
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ื”ื—ื™ืฉื•ื‘ื™ื ื”ื“ืจื•ืฉื™ื ื‘ื›ื“ื™ ืœืงื‘ื•ืข ืืช ืžื™ืงื•ื ื”ืกืคื™ื ื” ืžื›ืœ ืžื“ื™ื“ื” ื™ื›ืœื• ืœืงื—ืช ืฉืขื•ืช.
02:10
But sextants and clocks weren't useful unless sailors could use these tools to determine their position.
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ืื‘ืœ ื›ืœื™ื ื›ืžื• ืกืงืกื˜ื ื˜ ื•ืฉืขื•ื ื™ื ืœื ื”ื™ื• ืฉื™ืžื•ืฉื™ื™ื ืœื•ืœื ื™ื›ืœื• ืžืœื—ื™ื ืœืงื‘ื•ืข ื‘ืขื–ืจืชื ืืช ืžื™ืงื•ื ื”ืกืคื™ื ื”.
02:17
Fortunately, in the 1600s, an amateur mathematician had invented the missing piece.
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ืœืžืจื‘ื” ื”ืžื–ืœ, ื‘ 1600 ืžืชืžื˜ื™ืงืื™ ื—ื•ื‘ื‘ ืžืฆื ืืช ื”ื—ืœืง ื”ื—ืกืจ.
02:24
John Napier toiled for more than 20 years in his castle in Scotland to develop logarithms, a calculation device.
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ื’'ื•ืŸ ื ืคื™ื™ืจ ืขืžืœ ื‘ืžืฉืš ื™ื•ืชืจ ืž 20 ืฉื ื” ื‘ื˜ื™ืจื” ืฉืœื• ื‘ืกืงื•ื˜ืœื ื“ ื‘ื›ื“ื™ ืœืคืชื— ืœื•ื’ืจื™ืชืžื™ื, ื›ืœื™ ื—ื™ืฉื•ื‘ื™.
02:32
Napier's ideas on logarithms involved the form of one over E and the constant 10 to the seventh power.
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ืจืขื™ื•ื ื•ืชื™ื• ืฉืœ ื ืคื™ื™ืจ ืขืœ ืœื•ื’ืจื™ืชืžื™ื ื›ื•ืœืœื™ื ืืช ื”ืฆื•ืจื” ืฉืœ 1 ื—ืœืงื™ e ื•ืืช ื”ืงื‘ื•ืข ืฉืœ 10 ื‘ื—ื–ืงืช 7.
02:41
Algebra in the early 1600s was not fully developed,
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ืืœื’ื‘ืจื” ื‘ืชื—ื™ืœืช ื”ืžืื” ื” 17 ืœื ื”ื™ื™ืชื” ืžืคื•ืชื—ืช ื‘ืžืœื•ืื”,
02:45
and Napier's logarithm of one did not equal zero.
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ื•ื”ืœื•ื’ืจื™ืชื ืฉืœ 1 ืขืค"ื™ ื ืคื™ื™ืจ ืœื ื”ื™ื” ืฉื•ื•ื” ืœ 0.
02:49
This made the calculations much less convenient than logarithms with a base of 10.
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ื–ื” ื’ืจื ืœื—ื™ืฉื•ื‘ื™ื ืœื”ื™ื•ืช ื”ืจื‘ื” ืคื—ื•ืช ื ื•ื—ื™ื ืžืืฉืจ ื‘ืœื•ื’ืจื™ืชืžื™ื ืขืœ ื‘ืกื™ืก 10.
02:55
Henry Briggs, a famous mathematician at Gresham College in London,
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ื”ื ืจื™ ื‘ืจื™ื’ืก, ืžืชืžื˜ื™ืงืื™ ืžืคื•ืจืกื ืžืงื•ืœื’' ื‘ื’ืจื™ืฉื - ืœื•ื ื“ื•ืŸ,
02:59
read Napier's work in 1614, and the following year made the long journey to Edinburgh to meet Napier.
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ืงืจื ืืช ื”ืขื‘ื•ื“ื” ืฉืœ ื ืคื™ื™ืจ ื‘ 1614 ื•ื‘ืฉื ืช 1615 ืขืฉื” ืืช ื”ื“ืจืš ื”ืืจื•ื›ื” ืœืื“ื™ื ื‘ื•ืจื• ื‘ื›ื“ื™ ืœืคื’ื•ืฉ ืืช ื ืคื™ื™ืจ.
03:07
Briggs showed up unannounced at Napier's castle door
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ื‘ืจื™ื’ืก ื”ื’ื™ืข ืœืœื ื”ื–ืžื ื” ืœื˜ื™ืจื” ืฉืœ ื ืคื™ื™ืจ
03:11
and suggested that John switch the base and form of his logarithms into something much simpler.
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ื•ื”ืฆื™ืข ืœื’'ื•ืŸ ืœื”ื—ืœื™ืฃ ืืช ื”ื‘ืกื™ืก ื•ื”ืฆื•ืจื” ืฉืœ ื”ืœื•ื’ืจื™ืชืžื™ื ืฉืœื• ืœืžืฉื”ื• ืคืฉื•ื˜ ื”ืจื‘ื” ื™ื•ืชืจ.
03:18
They both agreed that a base of 10 with the log of one equal to zero
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ื”ื ืฉื ื™ื”ื ื”ืกื›ื™ืžื• ืฉืœื•ื’ืจื™ืชื ืฉืœ 1 ื‘ื‘ืกื™ืก 10 ื™ื”ื™ื” ืฉื•ื•ื” 0
03:23
would greatly simplify everyday calculations.
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ื“ื‘ืจ ืฉื™ืขืฉื” ืืช ื”ื—ื™ืฉื•ื‘ื™ื ื”ื™ื•ืžื™ื•ืžื™ื ืœืคืฉื•ื˜ื™ื ื”ืจื‘ื” ื™ื•ืชืจ.
03:26
Today we remember these as Briggs Common Logarithms.
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ื”ื™ื•ื ืื ื—ื ื• ื–ื•ื›ืจื™ื ืืช ื”ืœื•ื’ืจื™ืชืžื™ื ื”ืืœื• ื›ืœื•ื’ืจื™ืชืžื™ื ืฉืœ ื‘ืจื™ื’ืก.
03:30
Until the development of electric calculating machines in the 20th century,
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ืขื“ ืฉื”ื•ืžืฆืื• ืžื›ืฉื™ืจื™ ื—ื™ืฉื•ื‘ ืืœืงื˜ืจื•ื ื™ื™ื ื‘ืžืื” ื” 20,
03:35
any calculations involving multiplication, division, powers, and extraction of roots with large and small numbers
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ื›ืœ ื—ื™ืฉื•ื‘ ืฉื›ืœืœ ื›ืคืœ, ื—ื™ืœื•ืง, ื—ื–ืงื•ืช ื•ื—ื™ืœื•ืฅ ืฉืœ ืฉื•ืจืฉื™ื ืžืžืกืคืจื™ื ื’ื“ื•ืœื™ื ื•ืงื˜ื ื™ื
03:44
were done using logarithms.
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ื ืขืฉื” ื‘ืขื–ืจืช ืฉื™ืžื•ืฉ ื‘ืœื•ื’ืจื™ืชืžื™ื.
03:46
The history of logarithms isn't just a lesson in math.
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ื”ื”ื™ืกื˜ื•ืจื™ื” ืฉืœ ืœื•ื’ืจื™ืชืžื™ื ืื™ื ื” ืจืง ืฉื™ืขื•ืจ ื‘ืžืชืžื˜ื™ืงื”.
03:50
There were many players responsible for successful navigation.
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ื”ื™ื• ืฉื—ืงื ื™ื ืจื‘ื™ื ืฉื”ื™ื• ืื—ืจืื™ื™ื ืœืคื™ืชื•ื— ื˜ื›ื ื•ืœื•ื’ื™ื•ืช ื ื™ื•ื•ื˜.
03:54
Instrument makers, astronomers, mathematicians,
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ื™ื•ืฆืจื™ ืžื›ืฉื™ืจื™ื, ืืกื˜ืจื•ื ื•ืžื™ื, ืžืชืžื˜ื™ืงืื™ื,
03:57
and of course sailors.
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ื•ื›ืžื•ื‘ืŸ ืžืœื—ื™ื.
03:59
Creativity isn't only about going deep into one's field of work,
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ื™ืฆื™ืจืชื™ื•ืช ืื™ื ื” ืขื•ืกืงืช ืจืง ื‘ื”ืขืžืงืช ื”ื™ื“ืข ื‘ืชื—ื•ื ืื—ื“.
04:04
it's about cross-pollination between disciplines too.
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ื™ืฆื™ืจืชื™ื•ืช ืงืฉื•ืจื” ื’ื ืœื”ืคืจื™ื™ื” ื”ื“ื“ื™ืช ื‘ื™ืŸ ื”ื“ื™ืกืฆื™ืคืœื™ื ื•ืช ื”ืฉื•ื ื•ืช.
ืขืœ ืืชืจ ื–ื”

ืืชืจ ื–ื” ื™ืฆื™ื’ ื‘ืคื ื™ื›ื ืกืจื˜ื•ื ื™ YouTube ื”ืžื•ืขื™ืœื™ื ืœืœื™ืžื•ื“ ืื ื’ืœื™ืช. ืชื•ื›ืœื• ืœืจืื•ืช ืฉื™ืขื•ืจื™ ืื ื’ืœื™ืช ื”ืžื•ืขื‘ืจื™ื ืขืœ ื™ื“ื™ ืžื•ืจื™ื ืžื”ืฉื•ืจื” ื”ืจืืฉื•ื ื” ืžืจื—ื‘ื™ ื”ืขื•ืœื. ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ื”ืžื•ืฆื’ื•ืช ื‘ื›ืœ ื“ืฃ ื•ื™ื“ืื• ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ ืžืฉื. ื”ื›ืชื•ื‘ื™ื•ืช ื’ื•ืœืœื•ืช ื‘ืกื ื›ืจื•ืŸ ืขื ื”ืคืขืœืช ื”ื•ื•ื™ื“ืื•. ืื ื™ืฉ ืœืš ื”ืขืจื•ืช ืื• ื‘ืงืฉื•ืช, ืื ื ืฆื•ืจ ืื™ืชื ื• ืงืฉืจ ื‘ืืžืฆืขื•ืช ื˜ื•ืคืก ื™ืฆื™ืจืช ืงืฉืจ ื–ื”.

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