The science of friction -- and its surprising impact on our lives
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0:01 - 0:03I have to admit that it's a lot of fun
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0:03 - 0:05when people ask me what I do for my job,
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0:05 - 0:08because I tell them
I literally rub things together. -
0:09 - 0:10This sounds ridiculous,
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0:10 - 0:12just rubbing things together.
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0:13 - 0:16But it has a technical name:
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0:17 - 0:18tribology.
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0:18 - 0:22T-r-i-b-o-l-o-g-y,
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0:22 - 0:24from the ancient Greek word "tribos,"
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0:24 - 0:25which means "to rub."
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0:26 - 0:29It's a funny-sounding word
you've probably never heard before, -
0:29 - 0:30but I promise you,
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0:30 - 0:33discovering it changes your experience
with the physical world. -
0:33 - 0:36Tribology has given me amazing projects.
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0:36 - 0:40I've worked on materials that fly,
and I've worked on dog food -- -
0:40 - 0:44a combination that doesn't sound like
one person has any business doing -
0:44 - 0:46in the span of just a couple years,
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0:46 - 0:49until you start to view the world
through a tribological lens. -
0:50 - 0:52And I think you'll be surprised
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0:52 - 0:55at how significant
a little bit of tribology can be -
0:55 - 0:57in alleviating some very large problems.
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0:59 - 1:03Tribology is the study of friction,
wear and lubrication. -
1:04 - 1:06You have all experienced
all three of these things. -
1:07 - 1:10Remember the last time you tried
to move a heavy object across the floor, -
1:11 - 1:13and you could just feel
something resisting you? -
1:13 - 1:14That would be friction.
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1:15 - 1:17Friction is the force that opposes motion.
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1:18 - 1:21Wear is the loss or transfer of material.
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1:21 - 1:24It's the reason you have to replace
your favorite shoes, -
1:24 - 1:26because eventually the soles disappear.
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1:26 - 1:28Lubricants are used
to reduce friction and wear. -
1:28 - 1:32They loosen up those stubborn rusted bolts
that just otherwise will not budge. -
1:34 - 1:37But tribology is also defined
as the science of interacting surfaces -
1:37 - 1:38in relative motion.
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1:40 - 1:45So, interacting surfaces
in relative motion: -
1:45 - 1:47there are a lot of those in the world.
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1:47 - 1:51As you're sitting there right now,
are you wiggling your foot at all -
1:51 - 1:52or maybe shifting around in your seat?
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1:52 - 1:55Because guess what?
Tribology is happening. -
1:55 - 1:57Even the smallest shift in your seat
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1:57 - 2:00involves two surfaces
moving relative to each other. -
2:00 - 2:03And your tribological
interaction for the shift -
2:03 - 2:05will be different than
the person next to you. -
2:05 - 2:07This is because the clothes you're wearing
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2:07 - 2:09change the friction
between you and the seat. -
2:09 - 2:13If you're wearing silk, it's a little
easier to squirm around in the seat -
2:13 - 2:14than if you're wearing wool.
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2:14 - 2:16That's because the friction
is lower for silk. -
2:17 - 2:20If you're moving your ankle
or wiggling your ankle at all, -
2:20 - 2:22did it make a popping sound?
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2:22 - 2:24You've had that, right?
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2:24 - 2:26You get up, you move around,
and some joint cracks or pops. -
2:26 - 2:28Thank you for that sound, tribology.
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2:30 - 2:33That sound can come from the fluid
that lubricates your joints -
2:33 - 2:34just moving around.
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2:34 - 2:37You're essentially releasing
gas bubbles in that fluid. -
2:38 - 2:41That sound can also come from the tendons
simply moving over each other. -
2:41 - 2:43Pretty common in the ankle,
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2:43 - 2:45so any of my fellow
foot-wigglers out there -
2:45 - 2:49may suddenly find themselves curious
about the tribology of tendons. -
2:51 - 2:54But how does one become
a tribologist like me? -
2:55 - 2:57It starts when you're a kid, of course.
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2:57 - 2:58I was a ballerina growing up.
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2:58 - 3:01I reached the level
where I was dancing on my toes, -
3:01 - 3:02or "en pointe."
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3:03 - 3:06Now, when you're dancing en pointe,
you're wearing those amazing shoes, -
3:06 - 3:08but they can be slippery on the stage.
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3:09 - 3:12The last thing you want to do
when you're trying to dance on your toes -
3:12 - 3:13is to slip and fall.
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3:13 - 3:16So we had boxes of stuff called rosin.
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3:16 - 3:19We would step into the rosin,
put a light coating on our shoes. -
3:19 - 3:21Rosin comes from tree sap
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3:21 - 3:24and, in its powdered form,
makes things less slippery. -
3:25 - 3:27You learned real fast as a dancer
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3:27 - 3:29how much was the right amount
to put on your shoes, -
3:29 - 3:32because if you didn't put enough on,
you were probably going to slip -
3:32 - 3:35due to the low friction
between your shoe and the stage. -
3:35 - 3:36Best case scenario,
-
3:36 - 3:39you're the clumsy ballerina on stage,
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3:39 - 3:42but the worst case scenario
would be an injury. -
3:43 - 3:47Already, I was optimizing
and manipulating friction. -
3:47 - 3:50You see, I was destined
to be a tribologist. -
3:50 - 3:52(Laughter)
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3:53 - 3:55But you were also a junior tribologist.
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3:56 - 3:58When you used crayons or colored pencils,
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3:58 - 4:01you knew that the harder you pressed,
the darker the color. -
4:01 - 4:04You also knew this meant
you were going to have to sharpen -
4:04 - 4:06that crayon or colored pencil
more frequently, -
4:06 - 4:08because it was wearing down faster.
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4:09 - 4:12Now let's talk about
those enticing shiny waxed floors -
4:12 - 4:14that you just had to slide across.
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4:14 - 4:16You knew if you put on a pair of socks,
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4:16 - 4:19you were going to get
a really good slide across that floor. -
4:19 - 4:21Good luck trying to do that barefoot.
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4:21 - 4:24Master manipulators of friction.
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4:26 - 4:28All kids are tribologists.
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4:28 - 4:29What about us as adults?
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4:31 - 4:33At some point today,
you brushed your teeth. -
4:34 - 4:35I hope.
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4:35 - 4:36(Laughter)
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4:36 - 4:38This is tribology in action.
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4:38 - 4:41The toothpaste and toothbrush
are working to remove or wear -
4:41 - 4:42the plaque from your teeth.
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4:44 - 4:46For the record, my dad is a dentist.
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4:46 - 4:49Never thought my career was going
to circle back to the family business. -
4:49 - 4:52But one day, we found ourselves
speaking the same language -
4:52 - 4:56when I was tasked with developing a test
to investigate plaque removal. -
4:56 - 4:58Sounded simple enough,
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4:58 - 5:01until I started to look at it
as a tribologist, -
5:01 - 5:03and then it became incredibly complex.
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5:03 - 5:06You have hard materials --
those would be your teeth -- -
5:06 - 5:09soft materials like your gums,
the toothpaste, the toothbrush. -
5:09 - 5:12There's lubrication --
the form of saliva and water -- -
5:12 - 5:15the dynamics of the person
doing the brushing and more. -
5:16 - 5:19I promise if we put diamonds
in your toothpaste, -
5:19 - 5:21you're going to remove that plaque.
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5:21 - 5:23Probably going to remove
your teeth as well. -
5:24 - 5:27So there's a fine balance to be had
between wearing the plaque away -
5:27 - 5:29and not damaging your teeth and gums.
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5:31 - 5:33We're brushing our teeth because we ate.
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5:33 - 5:35Eating is another routine thing we all do.
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5:35 - 5:36Seems simple enough.
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5:36 - 5:38But it's another field of tribology,
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5:38 - 5:39and it's not so simple.
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5:40 - 5:43You have the food, which will break
and wear while you're eating, -
5:43 - 5:46and that food is interacting
with your teeth, your tongue, -
5:46 - 5:47your saliva, your throat.
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5:47 - 5:52And all of those interactions are going
to influence your experience of eating. -
5:53 - 5:56I think you can all recall a moment
where you tried something new -
5:56 - 5:58and you just found yourself going,
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5:59 - 6:01"Well, it tastes alright.
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6:01 - 6:03I really don't like that texture."
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6:04 - 6:07Tribologists are looking at lubricity,
the coefficient of friction, -
6:07 - 6:13as ways to connect mouth feel
and texture to what you're experiencing, -
6:13 - 6:16so that if we're changing the formulations
of what we're eating and drinking -
6:16 - 6:20so the sugar content
or fat content are different, -
6:20 - 6:21how does that change mouth feel?
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6:21 - 6:23How do we quantify that?
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6:23 - 6:26This is what tribologists
are looking to solve. -
6:26 - 6:29And while my colleagues
were in one corner of this lab -
6:29 - 6:31looking at the fat content of yogurt,
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6:31 - 6:32I was in another corner
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6:32 - 6:34studying dog food.
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6:34 - 6:36That lab smelled really good,
by the way, let me tell you. -
6:37 - 6:39We all brush our teeth on a regular basis.
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6:39 - 6:41How many of us brush our pets' teeth?
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6:43 - 6:46Animals as adults commonly get
periodontal disease, -
6:46 - 6:48so we really should be
brushing their teeth, -
6:48 - 6:50and more pet owners
are starting to do this. -
6:50 - 6:54I know my best friend is really great
at brushing her cat's teeth, somehow. -
6:54 - 6:56Good luck trying to do that with my cat.
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6:56 - 6:58So what pet food suppliers
are trying to do -
6:58 - 7:01is incorporate plaque removal
in things like treats. -
7:01 - 7:03If you have a dog,
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7:03 - 7:05you may have observed
that you give a dog a treat, -
7:05 - 7:08and it magically seems to disappear
after just one bite. -
7:08 - 7:10So the added challenge here is:
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7:10 - 7:12How do you remove plaque
when you have one bite? -
7:13 - 7:16I developed a benchtop test
to study this problem, -
7:16 - 7:18and to do so, I had to mimic
the oral system of dogs: -
7:18 - 7:22their teeth, plaque, saliva.
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7:22 - 7:24And I used friction and wear measurements
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7:24 - 7:27to study the effectiveness
of that treat on removing plaque. -
7:29 - 7:32If you're sitting there right now
thinking about the last time -
7:32 - 7:34you didn't brush your dog's teeth,
you're very welcome. -
7:34 - 7:36But what's the big deal with tribology?
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7:37 - 7:39Let me give you one more example.
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7:40 - 7:44No matter where you are right now,
you got to this location somehow. -
7:44 - 7:45Maybe you walked or rode your bike,
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7:45 - 7:48but for most people in this room,
you probably came in a car. -
7:49 - 7:52Just think about all
the tribological systems in a car. -
7:52 - 7:54You have your personal
interactions with the car, -
7:55 - 7:56the car's interactions with the road
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7:56 - 7:59and everything under the hood
and in the drivetrain. -
7:59 - 8:03Some routine maintenance
is directly connected to tribology. -
8:04 - 8:06You know how many miles
your tires are recommended for using -
8:06 - 8:08before you replace them.
-
8:08 - 8:10You regularly check
the treads on those tires. -
8:11 - 8:15You're actively monitoring
the wear of your tires. -
8:16 - 8:19Tribology is the study
of wear and friction, -
8:19 - 8:23and with tires, friction can be
the difference between a safe arrival -
8:23 - 8:24and a car accident.
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8:24 - 8:27This is because the friction
between your tires and the road -
8:27 - 8:30will influence your acceleration,
your deceleration -
8:30 - 8:32and your stopping distance.
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8:32 - 8:36As a driver, you instinctively
already know how important friction is, -
8:36 - 8:38because you know
that when the roads are wet, -
8:38 - 8:40they're more dangerous
because they're slippery. -
8:40 - 8:43This is because the water
is reducing the friction -
8:43 - 8:44between your tires and the road.
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8:44 - 8:47You may recall that friction
is the force that opposes motion, -
8:47 - 8:51so water reducing that force
means it's now easier for you to move, -
8:51 - 8:53hence it's more slippery
when the roads are wet. -
8:54 - 8:56Something else to consider
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8:56 - 8:58is that overcoming friction takes energy,
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8:59 - 9:01so you're losing energy to friction.
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9:02 - 9:05This is one way your tires
can influence your fuel efficiency. -
9:05 - 9:08And, in fact, did you know
that about one-third of the fuel -
9:08 - 9:11that you put into your
internal combustion engine vehicle -
9:11 - 9:13will be spent overcoming friction?
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9:14 - 9:15One-third.
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9:15 - 9:18Tribology research
has helped us reduce friction -
9:18 - 9:21and therefore increase
fuel efficiency and reduce emissions. -
9:22 - 9:25Holmberg and Erdemir have actually
done some great studies -
9:25 - 9:27showing the impact
tribology research can have -
9:27 - 9:28on reducing our energy consumption.
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9:28 - 9:32And they found that, looking over
the span of 20 years, -
9:32 - 9:33we had the opportunity to reduce
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9:33 - 9:36the energy consumption
of passenger vehicles -
9:36 - 9:37up to 60 percent.
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9:38 - 9:40When you think about
all the cars in the world, -
9:40 - 9:42that's a lot of energy we can save.
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9:42 - 9:47It's part of the nearly nine percent
of our current global energy consumption -
9:47 - 9:51that the authors identified
tribology can help us save. -
9:52 - 9:54That's a significant amount of energy.
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9:54 - 9:58So when you look at the numbers,
tribology can do some amazing things. -
9:59 - 10:01My colleagues have identified
up to 20 quads of energy -
10:01 - 10:04we can save across the US alone.
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10:04 - 10:05To put this in perspective:
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10:05 - 10:11one quad of energy is roughly equivalent
to 180 million barrels of oil, -
10:11 - 10:13and tribology can help us
save 20 times that. -
10:14 - 10:17This is through new materials,
new lubricants, -
10:17 - 10:19novel component design,
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10:19 - 10:22doing things like making wind turbines
more efficient and reliable. -
10:23 - 10:26This happened just by putting
31 people in a room -
10:26 - 10:28who viewed the world
through a tribology lens. -
10:29 - 10:32Imagine the opportunities
that will reveal themselves -
10:32 - 10:34as more of us start to see
tribology all around. -
10:35 - 10:38My favorite projects right now
are in aerospace applications. -
10:38 - 10:42I love reducing wear and friction
in these challenging environments. -
10:42 - 10:44I can make materials and parts
-
10:44 - 10:47that will reduce the friction
in moving components and engines -
10:47 - 10:50so that they have less force
opposing their motion. -
10:51 - 10:54Less force to move
means they require less power, -
10:54 - 10:56so you can use a smaller actuator,
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10:56 - 10:58which would weigh less,
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10:58 - 10:59which saves fuel.
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11:00 - 11:03I can also help make parts
that last longer through lower wear. -
11:04 - 11:05This will reduce material waste
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11:05 - 11:08and also means we're manufacturing
the parts less frequently, -
11:08 - 11:10so we're saving energy in manufacturing.
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11:11 - 11:14I encourage you to start seeing
tribology in the world around you -
11:14 - 11:19and to think about how you would improve
those interacting surfaces you experience. -
11:19 - 11:21Even the smallest improvements
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11:21 - 11:22really add up.
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11:23 - 11:26Tribology may be a funny-sounding word,
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11:26 - 11:29but it has a huge impact on our world.
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11:29 - 11:31Thank you.
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11:31 - 11:33(Applause)
- Title:
- The science of friction -- and its surprising impact on our lives
- Speaker:
- Jennifer Vail
- Description:
-
Tribology: it's a funny-sounding word you might not have heard before, but it could change how you see and interact with the physical world, says mechanical engineer Jennifer Vail. Offering lessons from tribology -- the study of friction and wear -- Vail describes the surprisingly varied ways it impacts everyday life and how it could help us make a better world.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 11:47
Oliver Friedman edited English subtitles for The science of friction -- and its surprising impact on our lives | ||
Oliver Friedman edited English subtitles for The science of friction -- and its surprising impact on our lives | ||
Oliver Friedman edited English subtitles for The science of friction -- and its surprising impact on our lives | ||
Oliver Friedman edited English subtitles for The science of friction -- and its surprising impact on our lives | ||
Brian Greene edited English subtitles for The science of friction -- and its surprising impact on our lives | ||
Erin Gregory approved English subtitles for The science of friction -- and its surprising impact on our lives | ||
Erin Gregory edited English subtitles for The science of friction -- and its surprising impact on our lives | ||
Camille Martínez accepted English subtitles for The science of friction -- and its surprising impact on our lives |