Why is cotton in everything? - Michael R. Stiff

2,272,448 views ใƒป 2020-01-23

TED-Ed


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

ืชืจื’ื•ื: Ido Dekkers ืขืจื™ื›ื”: Allon Sasson
00:06
Centuries ago, the Inca developed ingenuous suits of armor
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ืœืคื ื™ ืžืื•ืช ืฉื ื™ื, ื”ืื™ื ืงื” ืคื™ืชื—ื• ื—ืœื™ืคื•ืช ืฉืจื™ื•ืŸ ื’ืื•ื ื™ื•ืช
00:11
that could flex with the blows of sharp spears and maces,
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ืฉื™ื›ืœื• ืœื”ืชื’ืžืฉ ืžื•ืœ ืžื›ื•ืช ืฉืœ ื—ื ื™ืชื•ืช ื—ื“ื•ืช ื•ืจื•ืžื—ื™ื,
00:15
protecting warriors from even the fiercest physical attacks.
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ื•ื”ื’ื ื• ืขืœ ื”ืœื•ื—ืžื™ื ืืคื™ืœื• ืžื”ื”ืชืงืคื•ืช ื”ืคื™ื–ื™ื•ืช ื”ืงืฉื•ืชื‘ื™ื•ืชืจ.
00:20
These hardy structures were made not from iron or steel,
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ื”ืžื‘ื ื™ื ื”ืงืฉื•ื—ื™ื ื”ืืœื” ืœื ื”ื™ื• ืขืฉื•ื™ื™ื ืžื‘ืจื–ืœ ืื• ืคืœื“ื”,
00:24
but rather something unexpectedly soft: cotton.
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ืืœื ืžืžืฉื”ื• ืจืš ื‘ืื•ืคืŸ ืžืคืชื™ืข: ื›ื•ืชื ื”.
00:28
These thickly woven, layered quilts of cotton
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ื”ื’ืœื™ืžื•ืช ื”ืขื‘ื•ืช ื”ืืจื•ื’ื•ืช ืžืฉื›ื‘ื•ืช ืฉืœ ื›ื•ืชื ื”
00:31
could distribute the energy from a blow across a large surface area,
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ื™ื›ืœื• ืœืคื–ืจ ืืช ื”ืื ืจื’ื™ื” ืฉืœ ืžื›ื” ืขืœ ืคื ื™ ืฉื˜ื— ื’ื“ื•ืœ,
00:36
shielding warriors without restricting their mobility.
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ื•ื”ื’ื ื• ืขืœ ื”ืœื•ื—ืžื™ื ื‘ืœื™ ืœื”ื’ื‘ื™ืœ ืืช ื”ื ื™ื™ื“ื•ืช ืฉืœื”ื.
00:40
These seemingly contradictory featuresโ€”
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ืœืชื›ื•ื ื•ืช ื”ืžื ื•ื’ื“ื•ืช ืœื›ืื•ืจื” ื”ืืœื” --
00:42
strength and flexibility, softness and durabilityโ€”
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ื›ื•ื— ื•ื’ืžื™ืฉื•ืช, ืจื›ื•ืช ื•ืขืžื™ื“ื•ืช --
00:46
have their roots in the intricate biology of the nearly invisible cotton fiber.
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ื™ืฉ ืฉื•ืจืฉื™ื ื‘ื‘ื™ื•ืœื•ื’ื™ื” ื”ืžื•ืจื›ื‘ืช ืฉืœ ืกื™ื‘ื™ ื”ื›ื•ืชื ื” ื”ื›ืžืขื˜ ื‘ืœืชื™ ื ืจืื™ื.
00:52
These fibers begin life deep within a cotton flower,
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ื”ืกื™ื‘ื™ื ื”ืืœื” ืžืชื—ื™ืœื™ื ืืช ื”ื—ื™ื™ื ืขืžื•ืง ื‘ืชื•ืš ืคืจื— ื”ื›ื•ืชื ื”,
00:56
on the surface of a seed.
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ืขืœ ืคื ื™ ื”ืฉื˜ื— ืฉืœ ื”ื–ืจืข.
00:58
As many as 16,000 fibers will festoon a single seed,
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ืขื“ 16,000 ืกื™ื‘ื™ื ื™ืงื™ืคื• ื–ืจืข ื‘ื•ื“ื“,
01:03
bulging from the seedโ€™s surface like miniature water balloons.
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ื‘ื•ืœื˜ื™ื ืžืคื ื™ ื”ืฉื˜ื— ืฉืœ ื”ื–ืจืข ื›ืžื• ื‘ืœื•ื ื™ ืžื™ื ื–ืขื™ืจื™ื.
01:07
Each cotton fiber, no matter how large it grows,
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ื›ืœ ืกื™ื‘ ื›ื•ืชื ื”, ืœื ืžืฉื ื” ืœืื™ื–ื” ื’ื•ื“ืœ ื™ืฆืžื—,
01:10
is made of just one cell.
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ืขืฉื•ื™ ืžืชื ื‘ื•ื“ื“.
01:13
That cell has multiple layers of cell wall.
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ืœืชื ื™ืฉ ืฉื›ื‘ื•ืช ืžืจื•ื‘ื•ืช ืฉืœ ื“ื•ืคืŸ ื”ืชื.
01:16
After a few days, the sides of the first layer,
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ืื—ืจื™ ื›ืžื” ื™ืžื™ื, ื”ืฆื“ ืฉืœ ื”ืฉื›ื‘ื” ื”ืจืืฉื•ื ื”,
01:20
called the primary cell wall,
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ืฉื ืงืจื ืงื™ืจ ื”ืชื ื”ืจืืฉื™,
01:22
stiffen, pushing cell growth in one direction
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ืžืชืงืฉื”, ื•ื“ื•ื—ืฃ ืืช ื’ื“ื™ืœืช ื”ืชื ื‘ื›ื™ื•ื•ืŸ ืื—ื“
01:25
and causing the fiber to elongate.
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ื•ื’ื•ืจื ืœืกื™ื‘ ืœื”ืชืืจืš.
01:28
The fiber elongates quickly for about 16 days.
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ื”ืกื™ื‘ ืžืชืืจืš ื‘ืžื”ื™ืจื•ืช ื‘ืžืฉืš ื‘ืขืจืš 16 ื™ืžื™ื.
01:32
Then it begins the next stage: strengthening the cell wall.
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ืื– ื”ื•ื ืžืชื—ื™ืœ ืืช ื”ืฉืœื‘ ื”ื‘ื: ื”ืงืฉื—ืช ืงื™ืจ ื”ืชื.
01:36
It does this by making more of the carbohydrate cellulose.
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ื”ื•ื ืขื•ืฉื” ื–ืืช ืขืœ ื™ื“ื™ ื™ืฆื™ืจืช ืขื•ื“ ืฆืœื•ืœื•ื– ืคื—ืžื™ืžื ื™.
01:40
Cellulose will make up 34% of the cell wall at this stage
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ืฆืœื•ืœื•ื– ื™ื”ื•ื•ื” 34% ืžืงื™ืจ ื”ืชื ื‘ืฉืœื‘ ื–ื”
01:45
and swiftly increases.
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ื•ื™ื’ื‘ืจ ื‘ืžื”ื™ืจื•ืช.
01:47
This new growth also reinforces the cell wall
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ื”ื’ื“ื™ืœื” ื”ื—ื“ืฉื” ื”ื–ื• ื’ื ืžื—ื–ืงืช ืืช ืงื™ืจ ื”ืชื
01:50
by going against the grain of the existing wall.
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ืขืœ ื™ื“ื™ ืฆืžื™ื—ื” ื ื’ื“ ื”ืกื™ื‘ื™ื ืฉืœ ื”ืงื™ืจ ื”ืงื™ื™ื.
01:53
The strengthened wall is more rigid, restricting further growth.
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ื”ืงื™ืจ ื”ืžื—ื•ื–ืง ืงืฉื™ื— ื™ื•ืชืจ, ืžื” ืฉืžื’ื‘ื™ืœ ืขื•ื“ ืืช ื”ื’ื“ื™ืœื”.
01:58
That means if the fiber remodels its walls too early,
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ื–ื” ืื•ืžืจ ืฉืื ื”ืกื™ื‘ ืžื—ื–ืง ืืช ื”ืงื™ืจื•ืช ืฉืœื• ืžื•ืงื“ื ืžื“ื™,
02:01
it will be short,
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ื”ื•ื ื™ื”ื™ื” ืงืฆืจ,
02:02
and ultimately make rough, weak fabrics.
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ื•ื‘ืกื•ืคื• ืฉืœ ื“ื‘ืจ ื™ื™ืฆื•ืจ ื‘ื“ื™ื ื’ืกื™ื ื•ื—ืœืฉื™ื.
02:05
But if cell wall strengthening begins too late,
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ืื‘ืœ ืื ื”ืชื—ื–ืงื•ืช ืงื™ืจ ื”ืชื ืžืชื—ื™ืœื” ืžืื•ื—ืจ ืžื“ื™,
02:08
the wall wonโ€™t be sturdy enoughโ€”
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ื”ืงื™ืจ ืœื ื™ื”ื™ื” ื—ื–ืง ืžืกืคื™ืง --
02:10
producing fibers that are too weak to hold fabrics together well.
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ืžื” ืฉื™ื™ืฆืจ ืกื™ื‘ื™ื ื—ืœืฉื™ื ืžื“ื™ ืœื”ื—ื–ื™ืง ืืช ื”ื‘ื“.
02:15
In ideal growing conditionsโ€”
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ื‘ืชื ืื™ ื’ื“ื™ืœื” ืื™ื“ื™ืืœื™ื™ื --
02:17
with the right temperature, water, fertilizer, pest control, and lightโ€”
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ืขื ื”ื˜ืžืคืจื˜ื•ืจื” ื”ื ื›ื•ื ื”, ืžื™ื, ื“ืฉืŸ, ื—ื•ืžืจื™ ื”ื“ื‘ืจื”, ื•ืื•ืจ --
02:23
a cotton fiber can grow up to 3.6 centimeters long
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ืกื™ื‘ ื›ื•ืชื ื” ื™ื›ื•ืœ ืœื’ื“ื•ืœ ืœืื•ืจืš 3.6 ืกื ื˜ื™ืžื˜ืจ
02:28
with only a 25 micrometer width.
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ื‘ืขื•ื‘ื™ ืฉืœ 25 ืžื™ืงืจื•ืžื˜ืจ ื‘ืœื‘ื“.
02:32
Long, fine fibers can wrap around one another
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ืกื™ื‘ื™ื ืืจื•ื›ื™ื ื•ืขื“ื™ื ื™ื ื™ื›ื•ืœื™ื ืœื”ืชืœืคืฃ ืื—ื“ ืกื‘ื™ื‘ ื”ืฉื ื™
02:35
better than shorter, less fine fibers,
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ื˜ื•ื‘ ื™ื•ืชืจ ืžืงืฆืจื™ื ื•ืคื—ื•ืช ืขื“ื™ื ื™ื,
02:37
which means those long, fine fibers make stronger threads
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ืžื” ืฉืื•ืžืจ ืฉื”ืกื™ื‘ื™ื ื”ืืจื•ื›ื™ื ื•ื”ืขื“ื™ื ื™ื ื™ื•ืชืจ ื™ื•ืฆืจื™ื ื—ื•ื˜ื™ื ื—ื–ืงื™ื ื™ื•ืชืจ
02:41
that hang together better as fabric.
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ืฉืžื—ื–ื™ืงื™ื ื˜ื•ื‘ ื™ื•ืชืจ ื›ื‘ื“.
02:44
Cotton with these qualities has diverse usesโ€”
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ืœื›ื•ืชื ื” ืขื ื”ืชื›ื•ื ื•ืช ื”ืืœื• ื™ืฉ ืฉื™ืžื•ืฉื™ื ืžื’ื•ื•ื ื™ื --
02:47
from soft textiles to the U.S. dollar bill,
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ืžื˜ืงืกื˜ื™ืœื™ื ืจื›ื™ื ืœืฉื˜ืจ ื”ื“ื•ืœืจ ืฉืœ ืืจืฆื•ืช ื”ื‘ืจื™ืช,
02:50
which is 75% cotton.
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ืฉืขืฉื•ื™ ืž 75% ื›ื•ืชื ื”.
02:53
The next crucial stage of the cotton fiberโ€™s growth
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ื”ืฉืœื‘ ื”ืงืจื™ื˜ื™ ื”ื‘ื ืฉืœ ื’ื“ื™ืœืช ืกื™ื‘ ื”ื›ื•ืชื ื”
02:56
begins as it thickens its secondary cell wall
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ืžืชื—ื™ืœ ื›ืฉื”ื•ื ืžืขื‘ื” ืืช ืงื™ืจ ื”ืชื ื”ืžืฉื ื™ ืฉืœื•
02:59
by depositing large quantities of cellulose into the secondary layer.
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ืขืœ ื™ื“ื™ ื”ื ื—ืช ื›ืžื•ื™ื•ืช ื’ื“ื•ืœื•ืช ืฉืœ ืฆืœื•ืœื•ื– ื‘ืฉื›ื‘ื” ื”ืžืฉื ื™ืช.
03:04
Cellulose goes on to make up over 90% of the fiberโ€™s weight.
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ืฆืœื•ืœื•ื– ืžืžืฉื™ืš ืœื™ืฆื•ืจ ื™ื•ืชืจ ืž 90% ืžืžืฉืงืœ ื”ืกื™ื‘.
03:08
The more cellulose that gets deposited,
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ื›ื›ืœ ืฉืžื•ื ื— ื™ื•ืชืจ ืฆืœื•ืœื•ื– ,
03:10
the denser that secondary layer becomesโ€”
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ื›ืš ื”ืฉื›ื‘ื” ื”ืฉื ื™ื” ื ืขืฉื™ืช ื“ื—ื•ืกื” ื™ื•ืชืจ --
03:13
and this determines the strength of the final fiber.
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ื•ื–ื” ืงื•ื‘ืข ืืช ื”ื—ื•ื–ืง ืฉืœ ื”ืกื™ื‘ ื”ืกื•ืคื™.
03:16
This stage is essential for developing long-lasting material
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ื”ืฉืœื‘ ื”ื–ื” ื—ื™ื•ื ื™ ืœืคื™ืชื•ื— ื—ื•ืžืจ ืฉืžื—ื–ื™ืง ื–ืžืŸ ืจื‘
03:20
for the likes of, say, a t-shirt.
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ืœื“ื‘ืจื™ื ื›ืžื•, ื ื’ื™ื“, ื—ื•ืœืฆื•ืช ื˜ื™.
03:22
The garmentโ€™s capacity to withstand years of washing and wear
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ื”ื™ื›ื•ืœืช ืฉืœ ื”ื‘ื’ื“ ืœืขืžื•ื“ ื‘ืคื ื™ ืฉื ื™ื ืฉืœ ืฉื˜ื™ืคื” ื•ื‘ืœืื™
03:26
is largely determined by the density of that secondary cell wall.
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ื ืงื‘ืขืช ื‘ืขื™ืงืจ ืขืœ ื™ื“ื™ ื”ื“ื—ื™ืกื•ืช ืฉืœ ืงื™ืจ ื”ืชื ื”ืžืฉื ื™.
03:30
On the other hand,
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ืžืฆื“ ืฉื ื™,
03:31
its softness is strongly influenced by the length of the fiber,
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ื”ืจื›ื•ืช ืฉืœื• ืžืฉืคืขืช ืžืื•ื“ ืžื”ืื•ืจืš ืฉืœ ื”ืกื™ื‘,
03:35
established with the remodeling of the primary wall layer.
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ืฉื ืงื‘ืข ืขื ื”ืžื™ื“ื•ืœ ืžื—ื“ืฉ ืฉืœ ืฉื›ื‘ืช ืงื™ืจ ื”ืชื ื”ืจืืฉื™ืช.
03:40
Finally, after about 50 days, the fiber is fully grown.
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ืœื‘ืกื•ืฃ, ืื—ืจื™ ื‘ืขืจืš 50 ื™ื•ื, ื”ืกื™ื‘ื™ื ืกื™ื™ืžื• ืœื’ื“ื•ืœ.
03:44
The living matter within the cell dies off,
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ื”ื—ื•ืžืจ ื”ื—ื™ ื‘ืชื•ืš ื”ืชื ืžืช,
03:47
leaving behind only the cellulose.
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ื•ืžืฉืื™ืจ ืื—ืจื™ื• ืจืง ืืช ื”ืฆืœื•ืœื•ื–.
03:50
The dried cotton seed pod, or boll, that surrounds the fibers cracks open,
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ืชื ื”ื–ืจืขื™ื ื”ืžื™ื•ื‘ืฉ ืฉืœ ื”ื›ื•ืชื ื”, ืื• ื›ื“ื•ืจ, ืฉืžืงื™ืฃ ืืช ื”ืกื™ื‘ื™ื ื ืกื“ืง,
03:55
unveiling a burst of several thousand fiber cells in a fluffy mass.
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ื•ืžื’ืœื” ืคืจืฅ ืฉืœ ื›ืžื” ืืœืคื™ ืชืื™ ืกื™ื‘ ื‘ืžืกื” ืจื›ื”.
04:01
The thread-like fibers we seeโ€” thinner than a human hairโ€”
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ื”ืกื™ื‘ื™ื ื“ืžื•ื™ื™ ื”ื—ื•ื˜ ืฉืื ื—ื ื• ืจื•ืื™ื -- ื“ืงื™ื ื™ื•ืชืจ ืžืฉืขืจืช ืื“ื --
04:05
are the remains of those dense, dried out walls of cellulose.
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ื”ื ื”ืฉืืจื™ื•ืช ืฉืœ ื”ืงื™ืจื•ืช ื”ื“ื—ื•ืกื™ื ื”ืžื™ื•ื‘ืฉื™ื ืฉืœ ื”ืฆืœื•ืœื•ื–.
04:09
Tens of thousands of these fibers spun into yarn
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ืขืฉืจื•ืช ืืœืคื™ ืกื™ื‘ื™ื ืžืกื•ื‘ื‘ื™ื ืœื—ื•ื˜ื™ื
04:13
will go on to make everything from fabric, to coffee filters, diapers,
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ื™ืžืฉื™ื›ื• ืœื™ืฆื•ืจ ื”ื›ืœ ืžื‘ื“ื™ื, ืœืคื™ืœื˜ืจื™ื ืฉืœ ืงืคื”, ื—ื™ืชื•ืœื™ื,
04:17
and fishing nets.
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ื•ืจืฉืชื•ืช ื“ื™ื’.
04:19
And with the help of modern science,
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ื•ื‘ืขื–ืจืช ื”ืžื“ืข ื”ืžื•ื“ืจื ื™,
04:21
cotton might soon be softer, stronger, and more resilient than ever
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ื›ื•ืชื ื” ืชื•ื›ืœ ื‘ืงืจื•ื‘ ืœื”ื™ื•ืช ืจื›ื” ื™ื•ืชืจ, ื—ื–ืงื” ื•ืขืžื™ื“ื” ื™ื•ืชืจ ืžืื™ ืคืขื
04:26
as researchers investigate how to optimize its growth
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ื›ืฉืžื“ืขื ื™ื ื—ื•ืงืจื™ื ืื™ืš ืœืžื˜ื‘ ืืช ื”ื’ื“ื™ืœื” ืฉืœื”
04:29
based on nutrients, weather conditions, and genetics.
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ื‘ื”ืชื‘ืกืก ืขืœ ื—ื•ืžืจื™ื ืžื–ื™ื ื™ื, ืชื ืื™ ืžื–ื’ ืื•ื™ืจ ื•ื’ื ื˜ื™ืงื”.
ื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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