[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:08.31,0:00:11.04,Default,,0000,0000,0000,,Around 1159 A.D.,
Dialogue: 0,0:00:11.04,0:00:13.63,Default,,0000,0000,0000,,a mathematician called \NBhaskara the Learned
Dialogue: 0,0:00:13.63,0:00:19.100,Default,,0000,0000,0000,,sketched a design for a wheel\Ncontaining curved reservoirs of mercury.
Dialogue: 0,0:00:19.100,0:00:22.18,Default,,0000,0000,0000,,He reasoned that as the wheels spun,
Dialogue: 0,0:00:22.18,0:00:25.80,Default,,0000,0000,0000,,the mercury would flow to the bottom\Nof each reservoir,
Dialogue: 0,0:00:25.80,0:00:30.22,Default,,0000,0000,0000,,leaving one side of the wheel\Nperpetually heavier than the other.
Dialogue: 0,0:00:30.22,0:00:34.64,Default,,0000,0000,0000,,The imbalance would keep\Nthe wheel turning forever.
Dialogue: 0,0:00:34.64,0:00:37.57,Default,,0000,0000,0000,,Bhaskara's drawing was one of\Nthe earliest designs
Dialogue: 0,0:00:37.57,0:00:40.10,Default,,0000,0000,0000,,for a perpetual motion machine,
Dialogue: 0,0:00:40.10,0:00:46.74,Default,,0000,0000,0000,,a device that can do work indefinitely\Nwithout any external energy source.
Dialogue: 0,0:00:46.74,0:00:52.32,Default,,0000,0000,0000,,Imagine a windmill that produced\Nthe breeze it needed to keep rotating.
Dialogue: 0,0:00:52.32,0:00:57.37,Default,,0000,0000,0000,,Or a lightbulb whose glow provided\Nits own electricity.
Dialogue: 0,0:00:57.37,0:01:01.18,Default,,0000,0000,0000,,These devices have captured many\Ninventors' imaginations
Dialogue: 0,0:01:01.18,0:01:05.47,Default,,0000,0000,0000,,because they could transform \Nour relationship with energy.
Dialogue: 0,0:01:05.47,0:01:08.100,Default,,0000,0000,0000,,For example, if you could build \Na perpetual motion machine
Dialogue: 0,0:01:08.100,0:01:12.83,Default,,0000,0000,0000,,that included humans as part of its\Nperfectly efficient system,
Dialogue: 0,0:01:12.83,0:01:16.25,Default,,0000,0000,0000,,it could sustain life indefinitely.
Dialogue: 0,0:01:16.25,0:01:18.27,Default,,0000,0000,0000,,There's just one problem.
Dialogue: 0,0:01:18.27,0:01:20.36,Default,,0000,0000,0000,,They don't work.
Dialogue: 0,0:01:20.36,0:01:22.39,Default,,0000,0000,0000,,Ideas for perpetual motion machines
Dialogue: 0,0:01:22.39,0:01:27.41,Default,,0000,0000,0000,,all violate one or more \Nfundamental laws of thermodynamics,
Dialogue: 0,0:01:27.41,0:01:29.65,Default,,0000,0000,0000,,the branch of physics that describes\Nthe relationship
Dialogue: 0,0:01:29.65,0:01:32.54,Default,,0000,0000,0000,,between different forms of energy.
Dialogue: 0,0:01:32.54,0:01:37.44,Default,,0000,0000,0000,,The first law of thermodynamics says\Nthat energy can't be created or destroyed.
Dialogue: 0,0:01:37.44,0:01:41.58,Default,,0000,0000,0000,,You can't get out more energy\Nthan you put in.
Dialogue: 0,0:01:41.58,0:01:45.46,Default,,0000,0000,0000,,That rules out a useful\Nperpetual motion machine right away
Dialogue: 0,0:01:45.46,0:01:50.38,Default,,0000,0000,0000,,because a machine could only ever\Nproduce as much energy as it consumed.
Dialogue: 0,0:01:50.38,0:01:54.75,Default,,0000,0000,0000,,There wouldn't be any left over\Nto power a car or charge a phone.
Dialogue: 0,0:01:54.75,0:01:59.50,Default,,0000,0000,0000,,But what if you just wanted the machine\Nto keep itself moving?
Dialogue: 0,0:01:59.50,0:02:01.88,Default,,0000,0000,0000,,Inventors have proposed plenty of ideas.
Dialogue: 0,0:02:01.88,0:02:06.95,Default,,0000,0000,0000,,Several of these have been variations\Non Bhaskara's over-balanced wheel
Dialogue: 0,0:02:06.95,0:02:11.58,Default,,0000,0000,0000,,with rolling balls \Nor weights on swinging arms.
Dialogue: 0,0:02:11.58,0:02:13.24,Default,,0000,0000,0000,,None of them work.
Dialogue: 0,0:02:13.24,0:02:16.08,Default,,0000,0000,0000,,The moving parts that make one\Nside of the wheel heavier
Dialogue: 0,0:02:16.08,0:02:21.24,Default,,0000,0000,0000,,also shift its center of mass downward\Nbelow the axle.
Dialogue: 0,0:02:21.24,0:02:22.75,Default,,0000,0000,0000,,With a low center of mass,
Dialogue: 0,0:02:22.75,0:02:26.05,Default,,0000,0000,0000,,the wheel just swings back and forth\Nlike a pendulum,
Dialogue: 0,0:02:26.05,0:02:28.10,Default,,0000,0000,0000,,then stops.
Dialogue: 0,0:02:28.10,0:02:30.37,Default,,0000,0000,0000,,What about a different approach?
Dialogue: 0,0:02:30.37,0:02:33.69,Default,,0000,0000,0000,,In the 17th century, Robert Boyle\Ncame up with an idea
Dialogue: 0,0:02:33.69,0:02:36.41,Default,,0000,0000,0000,,for a self-watering pot.
Dialogue: 0,0:02:36.41,0:02:39.30,Default,,0000,0000,0000,,He theorized that capillary action,
Dialogue: 0,0:02:39.30,0:02:42.03,Default,,0000,0000,0000,,the attraction \Nbetween liquids and surfaces
Dialogue: 0,0:02:42.03,0:02:44.85,Default,,0000,0000,0000,,that pulls water through thin tubes,
Dialogue: 0,0:02:44.85,0:02:49.46,Default,,0000,0000,0000,,might keep the water cycling\Naround the bowl.
Dialogue: 0,0:02:49.46,0:02:53.01,Default,,0000,0000,0000,,But if the capillary action is strong\Nenough to overcome gravity
Dialogue: 0,0:02:53.01,0:02:54.73,Default,,0000,0000,0000,,and draw the water up,
Dialogue: 0,0:02:54.73,0:02:59.29,Default,,0000,0000,0000,,it would also prevent it from falling\Nback into the bowl.
Dialogue: 0,0:02:59.29,0:03:03.48,Default,,0000,0000,0000,,Then there are versions with magnets,\Nlike this set of ramps.
Dialogue: 0,0:03:03.48,0:03:07.36,Default,,0000,0000,0000,,The ball is supposed to be pulled\Nupwards by the magnet at the top,
Dialogue: 0,0:03:07.36,0:03:09.18,Default,,0000,0000,0000,,fall back down through the hole,
Dialogue: 0,0:03:09.18,0:03:11.35,Default,,0000,0000,0000,,and repeat the cycle.
Dialogue: 0,0:03:11.35,0:03:14.40,Default,,0000,0000,0000,,This one fails because like\Nthe self-watering pot,
Dialogue: 0,0:03:14.40,0:03:18.18,Default,,0000,0000,0000,,the magnet would simply hold\Nthe ball at the top.
Dialogue: 0,0:03:18.18,0:03:20.44,Default,,0000,0000,0000,,Even if it somehow did keep moving,
Dialogue: 0,0:03:20.44,0:03:23.18,Default,,0000,0000,0000,,the magnet's strength \Nwould degrade over time
Dialogue: 0,0:03:23.18,0:03:25.90,Default,,0000,0000,0000,,and eventually stop working.
Dialogue: 0,0:03:25.90,0:03:28.43,Default,,0000,0000,0000,,For each of these machines to keep moving,
Dialogue: 0,0:03:28.43,0:03:30.74,Default,,0000,0000,0000,,they'd have to create some extra energy
Dialogue: 0,0:03:30.74,0:03:34.08,Default,,0000,0000,0000,,to nudge the system \Npast its stopping point,
Dialogue: 0,0:03:34.08,0:03:37.60,Default,,0000,0000,0000,,breaking the first law of thermodynamics.
Dialogue: 0,0:03:37.60,0:03:39.69,Default,,0000,0000,0000,,There are ones that seem to keep going,
Dialogue: 0,0:03:39.69,0:03:43.15,Default,,0000,0000,0000,,but in reality, they invariably turn out\Nto be drawing energy
Dialogue: 0,0:03:43.15,0:03:46.18,Default,,0000,0000,0000,,from some external source.
Dialogue: 0,0:03:46.18,0:03:48.71,Default,,0000,0000,0000,,Even if engineers could \Nsomehow design a machine
Dialogue: 0,0:03:48.71,0:03:51.62,Default,,0000,0000,0000,,that didn't violate the first law\Nof thermodynamics,
Dialogue: 0,0:03:51.62,0:03:56.39,Default,,0000,0000,0000,,it still wouldn't work in the real world\Nbecause of the second law.
Dialogue: 0,0:03:56.39,0:03:58.12,Default,,0000,0000,0000,,The second law of thermodynamics
Dialogue: 0,0:03:58.12,0:04:03.34,Default,,0000,0000,0000,,tells us that energy tends to spread out\Nthrough processes like friction.
Dialogue: 0,0:04:03.34,0:04:05.68,Default,,0000,0000,0000,,Any real machine would have moving parts
Dialogue: 0,0:04:05.68,0:04:08.56,Default,,0000,0000,0000,,or interactions with air \Nor liquid molecules
Dialogue: 0,0:04:08.56,0:04:12.35,Default,,0000,0000,0000,,that would generate tiny amounts\Nof friction and heat,
Dialogue: 0,0:04:12.35,0:04:14.64,Default,,0000,0000,0000,,even in a vacuum.
Dialogue: 0,0:04:14.64,0:04:16.100,Default,,0000,0000,0000,,That heat is energy escaping,
Dialogue: 0,0:04:16.100,0:04:18.56,Default,,0000,0000,0000,,and it would keep leeching out,
Dialogue: 0,0:04:18.56,0:04:21.49,Default,,0000,0000,0000,,reducing the energy available\Nto move the system itself
Dialogue: 0,0:04:21.49,0:04:25.25,Default,,0000,0000,0000,,until the machine inevitably stopped.
Dialogue: 0,0:04:25.25,0:04:27.77,Default,,0000,0000,0000,,So far, these two laws of thermodynamics
Dialogue: 0,0:04:27.77,0:04:31.30,Default,,0000,0000,0000,,have stymied every idea \Nfor perpetual motion
Dialogue: 0,0:04:31.30,0:04:36.64,Default,,0000,0000,0000,,and the dreams of perfectly efficient\Nenergy generation they imply.
Dialogue: 0,0:04:36.64,0:04:41.75,Default,,0000,0000,0000,,Yet it's hard to conclusively say we'll\Nnever discover a perpetual motion machine
Dialogue: 0,0:04:41.75,0:04:46.55,Default,,0000,0000,0000,,because there's still so much we don't\Nunderstand about the universe.
Dialogue: 0,0:04:46.55,0:04:49.31,Default,,0000,0000,0000,,Perhaps we'll find \Nnew exotic forms of matter
Dialogue: 0,0:04:49.31,0:04:53.34,Default,,0000,0000,0000,,that'll force us to revisit the laws\Nof thermodynamics.
Dialogue: 0,0:04:53.34,0:04:58.60,Default,,0000,0000,0000,,Or maybe there's perpetual motion\Non tiny quantum scales.
Dialogue: 0,0:04:58.60,0:05:03.73,Default,,0000,0000,0000,,What we can be reasonably sure about\Nis that we'll never stop looking.
Dialogue: 0,0:05:03.73,0:05:08.21,Default,,0000,0000,0000,,For now, the one thing that seems\Ntruly perpetual is our search.