From DNA to Silly Putty, the diverse world of polymers - Jan Mattingly
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0:07 - 0:08What do silk,
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0:08 - 0:09DNA,
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0:09 - 0:09wood,
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0:09 - 0:10balloons,
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0:10 - 0:13and Silly Putty all have in common?
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0:13 - 0:15They're polymers.
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0:15 - 0:17Polymers are such a big part of our lives
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0:17 - 0:19that it's virtually impossible
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0:19 - 0:21to imagine a world without them,
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0:21 - 0:22but what the heck are they?
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0:22 - 0:24Polymers are large molecules
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0:24 - 0:27made of small units called monomers
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0:27 - 0:30linked together like the railroad cars from a train.
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0:30 - 0:31Poly means many,
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0:31 - 0:33and mono means one,
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0:33 - 0:36and mers or mero means parts.
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0:36 - 0:38Many polymers are made by repeating
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0:38 - 0:41the same small monomer over and over again
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0:41 - 0:42while others are made from two monomers
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0:42 - 0:44linked in a pattern.
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0:44 - 0:47All living things are made of polymers.
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0:47 - 0:49Some of the organic molecules in organisms
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0:49 - 0:51are small and simple,
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0:51 - 0:54having only one of a few functional groups.
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0:54 - 0:57Others, especially those that play structural roles
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0:57 - 0:59or store genetic information,
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0:59 - 1:01are macromolecules.
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1:01 - 1:04In many cases, these macromolecules are polymers.
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1:04 - 1:07For example, complex carbohydrates
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1:07 - 1:09are polymers of simple sugars,
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1:09 - 1:11proteins are polymers of amino acids,
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1:11 - 1:14and nucleic acids, DNA and RNA,
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1:14 - 1:16which contain our genetic information,
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1:16 - 1:18are polymers of nucleotides.
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1:18 - 1:20Trees and plants are made
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1:20 - 1:22of the polymer cellulose.
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1:22 - 1:24It's the tough stuff you find in bark and stems.
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1:24 - 1:25Feathers,
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1:25 - 1:26fur,
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1:26 - 1:26hair,
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1:26 - 1:27and fingernails
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1:27 - 1:29are made up of the protein keratin,
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1:29 - 1:31also a polymer.
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1:31 - 1:32It doesn't stop there.
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1:32 - 1:34Did you know that the exoskeletons
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1:34 - 1:36of the largest phylum in the animal kingdom,
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1:36 - 1:37the arthropods,
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1:37 - 1:39are made of the polymer chitin?
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1:40 - 1:42Polymers also form the basis
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1:42 - 1:45for synthetic fibers, rubbers, and plastics.
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1:45 - 1:48All synthetic polymers are derived from petroleum oil
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1:48 - 1:51and manufactured through chemical reactions.
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1:51 - 1:53The two most common types of reactions
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1:53 - 1:55used to make polymers
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1:55 - 1:56are addition reactions
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1:56 - 1:58and condensation reactions.
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1:58 - 1:59In addition reactions,
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1:59 - 2:03monomers simply add together to form the polymer.
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2:03 - 2:05The process starts with a free radical,
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2:05 - 2:08a species with an unpaired electron.
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2:08 - 2:09The free radical attacks
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2:09 - 2:12and breaks the bonds to form new bonds.
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2:12 - 2:14This process repeats over and over
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2:14 - 2:16to create a long-chained polymer.
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2:16 - 2:17In condensation reactions,
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2:17 - 2:19a small molecule, such as water,
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2:19 - 2:22is produced with each chain-extending reaction.
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2:22 - 2:24The first synthetic polymers
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2:24 - 2:25were created by accident
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2:25 - 2:28as by-products of various chemical reactions.
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2:28 - 2:29Thinking they were useless,
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2:29 - 2:32chemists mostly discarded them.
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2:32 - 2:34Finally, one named Leo Baekeland
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2:34 - 2:36decided maybe his useless by-product
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2:36 - 2:38wasn't so useless after all.
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2:38 - 2:40His work resulted in a plastic
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2:40 - 2:42that could be permanently squished into a shape
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2:42 - 2:45using pressure and high temperatures.
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2:45 - 2:46Since the name of this plastic,
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2:46 - 2:50polyoxybenzylmethylenglycolanhydride,
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2:50 - 2:51wasn't very catchy,
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2:51 - 2:54advertisers called it Bakelite.
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2:55 - 2:56Bakelite was made into telephones,
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2:56 - 2:57children's toys,
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2:57 - 3:00and insulators for electrical devices.
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3:00 - 3:02With its development in 1907,
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3:02 - 3:05the plastics industry exploded.
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3:05 - 3:07One other familiar polymer, Silly Putty,
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3:07 - 3:09was also invented by accident.
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3:09 - 3:10During World War II,
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3:10 - 3:12the United States was in desperate need
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3:12 - 3:14of synthetic rubber to support the military.
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3:14 - 3:16A team of chemists at General Electric
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3:16 - 3:18attempted to create one
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3:18 - 3:20but ended up with a gooey, soft putty.
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3:20 - 3:22It wasn't a good rubber substitute,
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3:22 - 3:24but it did have one strange quality:
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3:24 - 3:27it appeared to be extremely bouncy.
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3:27 - 3:29Silly Putty was born!
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3:29 - 3:31Synthetic polymers have changed the world.
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3:31 - 3:32Think about it.
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3:32 - 3:34Could you imagine getting through a single day
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3:34 - 3:36without using plastic?
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3:36 - 3:38But polymers aren't all good.
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3:38 - 3:41Styrofoam, for example, is made mainly of styrene,
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3:41 - 3:43which has been identified as a possible carcinogen
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3:43 - 3:46by the Environmental Protection Agency.
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3:46 - 3:48As Styrofoam products are being made,
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3:48 - 3:51or as they slowly deteriorate in landfills or the ocean,
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3:51 - 3:53they can release toxic styrene
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3:53 - 3:54into the environment.
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3:54 - 3:56In addition, plastics that are created
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3:56 - 3:58by addition polymerization reactions,
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3:58 - 3:59like Styrofoam,
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3:59 - 4:00plastic bags,
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4:00 - 4:01and PVC,
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4:01 - 4:03are built to be durable and food-safe,
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4:03 - 4:05but that means that they don't break down
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4:05 - 4:06in the environment.
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4:06 - 4:08Millions of tons of plastics
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4:08 - 4:10are dumped into landfills every year.
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4:10 - 4:12This plastic doesn't biodegrade,
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4:12 - 4:14it just breaks down
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4:14 - 4:16into smaller and smaller pieces,
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4:16 - 4:17affecting marine life
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4:17 - 4:20and eventually making their way back to humans.
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4:20 - 4:22Polymers can be soft or hard,
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4:22 - 4:23squishy or solid,
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4:23 - 4:25fragile or strong.
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4:25 - 4:27The huge variation between
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4:27 - 4:28means they can form
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4:28 - 4:31an incredibly diverse array of substances,
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4:31 - 4:31from DNA
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4:31 - 4:33to nylon stockings.
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4:33 - 4:35Polymers are so useful
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4:35 - 4:37that we've grown to depend on them every day.
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4:37 - 4:39But some are littering
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4:39 - 4:41our oceans, cities, and waterways
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4:41 - 4:42with effects on our health
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4:42 - 4:45that we're only beginning to understand.
- Title:
- From DNA to Silly Putty, the diverse world of polymers - Jan Mattingly
- Description:
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View full lesson: http://ed.ted.com/lessons/from-dna-to-silly-putty-the-diverse-world-of-polymers-jan-mattingly
You are made of polymers, and so are trees and telephones and toys. A polymer is a long chain of identical molecules (or monomers) with a range of useful properties, like toughness or stretchiness -- and it turns out, we just can't live without them. Polymers occur both naturally -- our DNA is a polymer -- and synthetically, like plastic, Silly Putty and styrofoam. Jan Mattingly explains how polymers have changed our world.
Lesson by Jan Mattingly, animation by TED-Ed.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 05:00
TED edited English subtitles for From DNA to Silly Putty, the diverse world of polymers - Jan Mattingly | ||
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Jessica Ruby accepted English subtitles for From DNA to Silly Putty, the diverse world of polymers - Jan Mattingly | ||
Jessica Ruby edited English subtitles for From DNA to Silly Putty, the diverse world of polymers - Jan Mattingly | ||
Jessica Ruby edited English subtitles for From DNA to Silly Putty, the diverse world of polymers - Jan Mattingly | ||
Andrea McDonough edited English subtitles for From DNA to Silly Putty, the diverse world of polymers - Jan Mattingly |