- 3 hours ago
Michael looks at how power has been harnessed from wind, steam and from inside the atom, and how it has changed the course of history.
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00:02There are some great questions that have intrigued and haunted us since the dawn of humanity.
00:11What is out there?
00:17How did we get here?
00:23What is the world made of?
00:29The story of our search to answer those questions is the story of science.
00:36Of all human endeavours, science has had the greatest impact on our lives, on how we see the world, on
00:43how we see ourselves.
00:45Its ideas, its achievements, its results are all around us.
00:52So, how did we arrive at the modern world?
00:56Well, that is more surprising and more human than you might think.
01:06The history of science is often told as a series of eureka moments, the ultimate triumph of the rational mind.
01:13But the truth is that power and passion, rivalry and sheer blind chance, have played equally significant parts.
01:24In this series, I'll be offering a different view of how science happens.
01:30It's been shaped as much by what's outside the laboratory as inside.
01:34Oh, whoa!
01:38This is the story of how history made science and science made history.
01:43And how the ideas that were generated changed our world.
01:47It is a tale of power, proof and passion.
01:54Passion.
02:04This time, an ancient human ambition, the search for limitless power.
02:26We are the most power-hungry generation that has ever lived.
02:30Energy is the heartbeat of our civilization.
02:37The pursuit of power has created and destroyed fortunes.
02:41It has raised and toppled nations.
02:44And it has utterly transformed how we live our lives.
02:52But this relentless search for more power has an importance that is far greater than discovering what it can do
03:00for us.
03:01When people ask themselves, what is power, as opposed to simply, where can I get more of it?
03:07Well, that led to some of the greatest insights in the whole history of science.
03:25The 17th century was a pivotal age, when the balance between man and nature began to change forever.
03:35There was no electricity.
03:38There were no cars, no trains.
03:42The most common power sources had to be fed and watered.
03:48Horsepower meant just that.
03:57But a remote beach in Holland would provide a glimpse of what was to come.
04:19If you had been walking along a beach in North West Holland 400 years ago, you might have seen a
04:26much larger version of one of these zip paths.
04:33It was called the Wind Chariot.
04:38Designed to carry heavily armoured soldiers along the coastline, it amazed and terrified in equal measure.
04:49Here was the power of the wind being harnessed to produce motion on land.
04:56It must have been an extraordinary sight.
04:58Oh, yes.
04:59The people were afraid of it and they called it a devil's rig.
05:04The devil's rig.
05:06Very dramatic, yes.
05:08How fast?
05:08It could outpace a horse running.
05:11Outpace a horse.
05:12So that must have made it one of the fastest things in the world at the time.
05:15Probably one of the fastest things.
05:17Using wind power?
05:18Just wind power.
05:20Very impressive.
05:25The wind chariot was designed by an engineer and mathematician called Simon Stevan.
05:31A remarkable man who would literally change the face of Holland and help turn it into a great trading empire.
05:42Because Stevan's ambitions for wind power went far beyond chariots.
05:48He wanted to transform his country using mathematics.
05:57Mathematics was changing.
06:00For hundreds of years in the universities, geometry and arithmetic had been important theoretical pursuits.
06:08Practical applications like building bridges and firing cannons were limited.
06:14But now, men like Simon Stevan would use math theory to create something much bigger.
06:21A new, mathematically grounded science.
06:25And that would help them solve a whole range of complex problems.
06:39Now, Stevan was clearly a mathematician who didn't mind getting his hands dirty.
06:44He saw the value of applying mathematical knowledge to the solution of practical problems.
06:51The problem Stevan turned his mathematics to was a crucial one in low-lying Holland.
06:58How to keep the country dry.
07:03For over a century, Holland's windmills had been scooping water from drainage ditches, tipping it into canals to carry it
07:11away.
07:13But Stevan was convinced that mathematics could make windmills much more efficient.
07:22We're at the top of the windmill now and this is the gearing system.
07:25This was the heart of what Stevan did.
07:28Mathematically, it's interesting because what he's done is there is no whole number relationship.
07:32It's not like two to one, three to one, between this and this.
07:35There is an irregular relationship.
07:38Also, you can probably see these things are angled.
07:41It is not a simple vertical plane meeting a horizontal plane.
07:46It's going at an angle.
07:47And that is really quite difficult to deal with mathematically as well.
07:50It looks crude, but it is fantastically refined.
07:54It's very impressive. I'm looking forward to seeing the whole thing run.
08:14It's magnificent, isn't it? It's like being inside an enormous clock.
08:21Standing here, you get the impression of immense, inexorable power.
08:27Which is sort of just driving around and around.
08:29And the thing which surprises me is it is so quiet.
08:34And that is a tribute to Stevan's mathematics.
08:38Because he obviously got it right.
08:39The interactions all work. There's very little clanking.
08:43If all that power was being wasted in sound and heat, this whole place would be vibrating.
08:48But actually, it's very smooth.
08:50Absolutely.
08:54This new, mathematically designed windmill was three times more efficient than the ones it replaced.
09:04It's almost poetic.
09:06I mean, this is a mathematical model realized in a physical reality.
09:15Stevan designed new paddle wheel shapes, sluices, even a chain of windmills,
09:21that could be used to drain not just fields, but a lake.
09:28What's more, he patented his many inventions to ensure that his work would be well rewarded.
09:35Mathematics made Stevan rich.
09:37And it wasn't long before it started to change the whole country.
09:45Simon Stevan had shown what really well designed windmills were capable of.
09:50And people now began to ask themselves, if they could drain lakes, what else could they do?
10:01Holland was already an emerging European force.
10:04Now the power of windmills helped turn it into an industrial powerhouse.
10:26Seeds and nuts were ground to extract their valuable oil.
10:35Paper mills became mechanized.
10:42Wood could be cut 30 times faster and with greater precision than by hand.
10:52Helping to turn this small country into the biggest shipbuilders in Western Europe.
11:03To the sound of mathematically designed mills whirring in the wind,
11:08Holland became an even more dynamic trading nation.
11:16And Amsterdam, one of the richest and most cosmopolitan cities on Earth.
11:24Here you could buy almost anything. Diamonds, furs, exotic spices.
11:30Amsterdam was enjoying a golden age.
11:34The city produced the first central bank, the first stock exchange and the first economic crash.
11:47The growth of Holland changed the power map of Europe.
11:52It had been helped by advances in windmill design.
11:57A new mathematically based science.
12:01And a belief amongst men like Simon Stevan that science should be useful.
12:08It was obvious what power could do.
12:12But what was still missing was any scientific understanding of what power actually is.
12:25That would only begin to emerge far later, on the other side of the channel.
12:38The English country house of the 18th century was a place of intrigue, romance and gossip.
12:51But between visits from dashing cavalry officers, these bastions of high society also hosted the occasional visiting experimenter.
13:03The home of an unlikely alliance that marked the birth of a world-changing new source of power.
13:15Science had become popular entertainment for the drawing room.
13:21Most of these contraptions had been developed to explore the wonders of the age, like static charge and magnetism.
13:34Now that really is impressive.
13:39Now this was a real crowd pleaser.
13:42The vacuum trick.
13:43What you do is you take an alarm.
13:47Set it to go off.
13:50Then put it in here.
13:55And pump out the air.
13:59Right.
14:00The alarm clock goes off.
14:03And you hear absolutely nothing.
14:08No one fully understood the science behind these demonstrations.
14:15But the ability to dazzle and intrigue helped bring new ideas to a new and attentive audience.
14:24Matthew Bolton was an entrepreneur who belonged to the lunar society.
14:30So called because they met on the night of the full moon.
14:34They were industrialists, experimenters and natural philosophers.
14:39Who all shared a love of practical knowledge.
14:46A leading lunar man was Scottish engineer, James Watt.
14:54For some years, Watt had been working with prototype steam engines.
14:59And this prompted Matthew Bolton to invite him to take part in a joint business venture.
15:06He had heard that Watt was trying to develop a new type of steam engine.
15:10As he later wrote to Watt, the reasons for backing him were twofold.
15:15Love of you, and love of a money-getting ingenious project.
15:20Now the plan was clear.
15:22Bolton had the capital. Watt had the idea.
15:25Together they would get seriously rich.
15:27This was capitalism in action.
15:38The steam engine had enormous global impact.
15:41And yet the surprising thing is, there was hardly any scientific theory behind it.
15:49That would come later.
15:56This is a Bolton and Watt steam engine.
15:58And this is the familiar bit.
16:00Man, coal, furnace.
16:02But what you might not expect is it is stationary and it is vast.
16:07This single machine occupies the whole building.
16:23So vast that this engine, originally built to keep the nearby canal topped up with water, boasts its very own
16:31driver.
16:36Hi there.
16:38Hello.
16:39Nice to see you.
16:39You're the driver.
16:40Yes, I'm the driver of this engine.
16:43I'm amazed.
16:44This is still working, isn't it?
16:46This is actually doing the job.
16:47This, at this moment, is actually maintaining the canal.
16:50The electric pumps, which British waterways normally use, are switched off and we're actually doing that job.
16:55Can I have a go at driving?
16:56You certainly can.
16:57I'll have to step round this lever.
16:59I've always wanted to drive a steam engine.
17:01This wasn't quite what I'd imagined.
17:03Right.
17:03Right, okay.
17:04Yes.
17:04So, okay.
17:06To the left.
17:06To the left, about a quarter of a turn.
17:10There's a sort of narrow window between strange bits.
17:13There is.
17:13There are indeed.
17:15What drove the engine was not so much the power of the steam directly, rather an industrial version of that
17:23country house trick, the vacuum.
17:26The steam is injected, then cooled, creating a vacuum.
17:31It's this which drags the piston head down, providing the engine with its lifting power.
17:38Close it another quarter of a turn.
17:46What's that?
17:47Well, you actually closed it too far.
17:49Okay, stop.
17:52A bit more.
17:53It's just, it's not good.
17:54It's not good.
17:55I was thinking this is really quite simple and then within literally 30 seconds of taking charge of this machine,
18:01I managed to stop it, which is quite impressive.
18:03Do you think we're back in control?
18:05That's looking good.
18:11James Watt didn't invent the steam engine, or even the idea of using a vacuum.
18:17Engines have been powered this way for decades.
18:21What's fame, and that of his machine, rests instead on one small modification.
18:28Located here, right at the bottom of the engine.
18:33It may not look like much, but down there is James Watt's unique contribution for the story of power.
18:39It's called a separate condenser.
18:42It's where the steam was cooled to create the all-important vacuum, well away from the hot cylinders.
18:50A small but ingenious technical innovation with enormous benefits.
18:57The Bolton and Watt steam engines were far more efficient than their rivals.
19:01They used a quarter of the amount of coal.
19:07The potential savings were enormous, something any businessman could understand.
19:12Over to you.
19:19Why some ideas change the world, while others languish, unloved and unnoticed, is seldom down to their intrinsic merit.
19:36The success of Bolton and Watt's engine was not just due to new technology, but also a clever piece of
19:44financial engineering.
19:49The machines were complicated and needed someone to install them.
19:53And that someone was, more often than not, James Watt himself.
19:57In his letters he complains bitterly about all the travelling he had to do.
20:03Walk on.
20:04Get up boys, go on, go on.
20:09And you can sort of see why, can't you?
20:12Lots of jolting.
20:13Now this is bearable, short trip, middle of summer.
20:16But imagine there, it's cold, it's winter, it is absolutely lashing down.
20:21Completely different experience.
20:26But the discomfort of 18th century travel was a price worth paying.
20:31Because once his engines had been installed, the money began to flood in.
20:38This three-page document was the key to Bolton and Watt's wealth.
20:41It's a patent.
20:43It covers Watt's adaptations to the steam engine.
20:46Now you had to go on paying royalties year after year, long after the machine was installed.
20:52Any savings you made from the machine, a portion went straight back to them.
20:59I think it's very telling how scientific discovery is rarely far away from the smell of money.
21:05And that's especially true of the search for power.
21:19But for all the riches on offer, there was still no real scientific framework to explain what power actually is.
21:28Science would have to wait till steam power became a force throughout the land.
21:44The big demand for steam engines was in the West Country, pumping flood water from mines.
21:51Their owners soon became reliant on Bolton and Watt's more efficient machines.
21:57Some mine owners, fed up with royalties, stopped paying.
22:01Bolton and Watt got tough and responded with legal writs.
22:06It's said that the delivery man who came to one of these mines was seized by the ankles, hung over
22:12the mine shaft and asked if he still wanted to deliver that writ.
22:16The man behind that particular story was Richard Trevithick.
22:22To get round of Watt's patent, Trevithick began to build his own engines.
22:35This was his greatest achievement, the puffing devil.
22:39All eight horsepower of it.
22:48And unlike Bolton and Watt's engine, it moved.
22:58Trevithick's genius was he built high pressure steam engines where the steam drive the piston.
23:05So he didn't need vacuums or condensers.
23:09Instead of being the size of houses, history mansions were small, powerful, mobile.
23:17And there's an added bonus.
23:19They produced that wonderful woo-woo noise.
23:23That's the sound of high pressure steam escaping.
23:43I'd read that people thought they were incredibly dangerous, that people thought not unreasonable that they would blow up in
23:49the high pressure system.
23:50You're quite right.
23:51They didn't have the knowledge of metallurgy that we do today.
23:55And yes, they did get boiler explosions.
23:57There's no enormous risk of this particular one blowing up.
23:59Not at all. Not at all.
24:02This new steam engine clearly pointed to a better way of moving goods and people around.
24:09Yet, Trevithick has not gone down in history as the father of the modern railway.
24:17I gather that he actually did on one occasion manage to get his steam car, if you like, on a
24:24track, on a railway.
24:25Why didn't it work?
24:26The engine weighed five tonnes or so, and so the rails broke under the weight of the engine.
24:31So the problem was not actually the train at all, it was simply the rail it was running on.
24:35Absolutely. Yes, the engine worked in the dream.
24:38Right, that is incredibly ironic, isn't it?
24:40Yeah, frankly.
24:46The history of science is full of moments like this.
24:50Great ideas have to come at the right place and the right time.
24:56Sadly for Trevithick, the place and time were wrong.
25:02So why didn't he die rich and famous?
25:05Well, it's partly because he didn't have his own Matthew Bolton to get his inventions out there
25:11and to make sure he was raking in the cash.
25:13But it's also because his ideas were well ahead of their time.
25:17In the early 1800s, if you wanted to get from A to B, you were better off buying a horse.
25:27Steam engines would eventually bring unprecedented change.
25:32Born out of a combination of different forces.
25:36The lunar society where men of science and business could meet and exchange ideas.
25:43Technical innovations like high-pressure steam.
25:47The promise of money and the protection of patents.
26:02From all this emerged a previously unimaginable source of power.
26:16The mechanical equivalent of countless forces to work the factories and mills of the 19th century landscape.
26:32The steam engines, their profits, their owners, these were the forces shaping Victorian Britain.
26:46But the effects of all this power were felt far beyond the world of heavy industry.
26:52The new aristocracy of factory owners and businessmen knew just how they wanted to use their newfound influence.
27:02Some used their wealth to campaign for social change, like the abolition of slavery or the education of women.
27:09The search for power had given political power to a new group of people, the middle classes.
27:17The quest for power had produced so much, but with no more scientific understanding than had existed a century before.
27:26Only now, belatedly, came the theorists.
27:39The victorians were utterly entranced by the power of steam.
27:44But the science behind it posed some of the greatest questions of the age.
27:51It demanded a new theory, a new way of looking at nature.
27:57Fortunately, help was at hand.
28:03This is Mrs Beaton's book of household management, a Victorian classic,
28:08which contains pretty well everything you need to know about how to run a household efficiently and well,
28:14including how to sack your servants.
28:18Frugality and economy are virtues, without which no household can prosper.
28:25Mrs Beaton, like so many in Victorian society, was obsessed with efficiency.
28:32Waste was not just uneconomical, it was also unchristian.
28:38In the kitchen, if you had old bones, you made soup.
28:41If you had old bread, you made a pudding.
28:44And this obsession was shared by the scientific community.
28:48In fact, it led to the development of a whole new concept, that of energy.
28:57As the steam engines took off, people became interested in comparing which engines were most efficient.
29:07A new theory of energy would now help them make precisely that sort of judgement.
29:17No one really knew what energy is.
29:20Some people thought of it as a fluid, which flows from one place to another.
29:25But what was becoming increasingly clear is it could be transferred.
29:32The steam engine, like a kettle, could be explained scientifically.
29:37As it burns, chemical energy from the coal is turned into heat.
29:43This energy heats the kettle and the water inside, which turns into steam, which can then be used to perform
29:52work.
29:54It sounds really simple, but this was a turning point in science.
29:59For the first time, such diverse things as heating coals, warming water, production of steam, even the spinning of windmills,
30:08could all be united by a single concept, that of energy.
30:13It led to the formulation of a new law of physics, one that is absolutely fundamental.
30:20It's called the first law of thermodynamics.
30:25The first law of thermodynamics is a mathematical description of energy, known as conservation of energy.
30:33It states that energy cannot be created or destroyed, so you can never get more out than is contained in
30:44the fuel you put in.
30:49And it applies to every source of power there is, from kettles, to steam engines, to windmills.
31:01Everything.
31:08Thermodynamics was one of the crowning glories of 19th century science.
31:14Inspired in part by the need to explain that wonder of the age, the steam engine.
31:21And by an obsession with thrift and efficiency.
31:27Thermodynamics was only one component of what was to be a far more comprehensive theory of energy and power.
31:57In June 1772, a small sailing expedition set off for the coast of France, on a voyage
32:06that would help point science towards the modern age.
32:15Its leader was John Walsh, recently retired from the British East India Company.
32:21Walsh was fascinated by the electricity found in nature.
32:30He went looking for it, not in the skies, but underwater.
32:37In a fish.
32:45The torpedo fish, which uses electric shocks to catch its prey.
33:01Walsh wanted to find out whether the power emitted by this strange fish was the same as that given off
33:08by lightning.
33:11Or a spark generator.
33:16Having done numerous experiments on himself and his crew, Walsh now headed back to London to try and find out
33:24just how the torpedo fish produced electric shocks.
33:34Some of the fish Walsh brought back are still preserved at the Hunterian Museum in London.
33:40They were dissected by the renowned surgeon John Hunter to reveal some very peculiar organs.
33:50Well, you see these two patches of white tissue, one top, one bottom, either side of the fish.
33:57These are things which Hunter hadn't seen before in other fish, other rays that he'd dissected.
34:04Right, this one looks very different.
34:06Well, it's a much more detailed dissection, but also Hunter's worked a bit of magic on it by injecting it
34:12with a red dye to show where the blood vessels are.
34:17The electric charge seemed to come from these tiny cells, now known as electrocytes, found within the electric organs.
34:27It is extraordinary because you begin to see where the charge would have come from.
34:31You can actually see each of the cells.
34:33It is beautiful, isn't it?
34:35I mean, it really is.
34:36It's a work of art.
34:36It is a work of art in its own right, isn't it?
34:41Walsh was convinced that the electricity from the torpedo fish was not only the same as the electricity in lightning,
34:49but that it must be possible to produce it using a machine.
34:55But plenty of people did not agree with Walsh.
34:58It seemed almost sacrilegious to claim that electricity from a machine made by man was exactly the same as electricity
35:06from a fish which had been created by God.
35:13And yet, proof that this was the case was not far away.
35:29In the archives of the Royal Society in London sits a letter that dates back to 1800.
35:38Written by an Italian scientist, Alessandro Volta, essentially it contains instructions on how to build your very own torpedo fish.
35:58This is a copy of the letter that Volta sent to the Royal Society.
36:02It's in French.
36:03It's got a useful diagram over in the corner.
36:06I've also got a box here of bits and pieces.
36:09Right.
36:10First of all, I need some zinc and some copper.
36:16Also, I need some bits of cardboard or tissue capable of soaking up a briny solution.
36:29It is very hard to believe this is actually going to do anything.
36:35We shall see.
36:41A piece of copper on the top and I've got a lead on it.
36:46Now, if you look at it closely, it really does resemble the working bits, if you like, of the torpedo
36:54fish.
36:56And he suggested to call it an artificial electric organ.
37:03The Voltaic pile, as it became known, could generate a significant electric current.
37:12Volta couldn't measure it, but he could demonstrate that it delivered a shock, just like the torpedo fish.
37:24What's interesting is that Volta, when he writes to the Royal Society, he effectively gives away all his secrets.
37:31Which is a bit of a shame for him, because this turned out to be one of the greatest technological
37:37discoveries of all time.
37:38It is, of course, the battery.
37:48What is really surprising, looking at it from a modern perspective, is that for a long time, people had no
37:54idea what to do with the battery.
37:55It had no obvious practical application.
37:57There was nothing to plug it into.
37:59It would be a generation before somebody managed to find a really significant practical use.
38:06An ingenious response to a rather urgent problem.
38:17On the 18th of June, 1815, the armies of the Duke of Wellington and the Emperor Napoleon met at Waterloo.
38:28It was a battle on whose outcome rested the fate of Europe.
38:36By the end of the day, the battle was over.
38:39The French had lost.
38:40Wellington was keen to get this good news to London as quickly as possible.
38:45Major Henry Percy was ordered to carry the message.
38:50He mounted his battle-weary horse and rode off across Belgium until he got to the coast.
38:55When he arrived, he had to wait for the correct wind and tide before finally he could set sail for
39:01England.
39:03In all, it took him four days to reach London.
39:06Four days during which I'm sure the people in the war office were biting their fingernails with anxiety, because many
39:13expected the French to win.
39:15Now, if you could have got a secret message from Waterloo to London faster than Major Percy, you could have
39:22made a fortune, betting on an improbable English victory.
39:29There was clearly a need for faster communication.
39:35Walter's pile was about to get plugged into something useful.
39:41And this time, it was science that led the way, thanks to a man called Hans Christian Ørsted.
39:51The story goes, he was about to give a lecture and he was preparing his equipment.
39:56Amongst it, he had a voltaic pile and some wire.
39:59When he connected up the wire, something utterly unexpected happened.
40:08The needle of a nearby compass twitched.
40:12And every time he connected the wire, or disconnected, it moved again.
40:21People had known for centuries that compass needles were deflected by magnets.
40:28Somehow, the electric current in the wire was also acting like a magnet, deflecting the needle, which left Ørsted completely
40:37baffled.
40:39Now, he obviously realised this was important, because he did further research and he published his findings.
40:46But I think it's extremely unlikely he ever appreciated just what a massive impact his discovery would make on the
40:54world.
40:57Within a few years, that twitching compass needle had grown into the electric telegraph.
41:08The power of electricity could now be used to get messages from A to B almost instantaneously.
41:16Telegraph cables were soon running right across the globe.
41:25And when the telegraph came together with that other great invention, the steam engine, the combination was unstoppable.
41:39Steam power did the heavy work, draining mines, spinning cotton, powering a new railway network.
41:49And with a telegraph that ran alongside those same railways, the battery brought control, political and financial.
42:01Together, they helped build the empires of 19th century Europe.
42:11The stage was now set for the next step in the scientific understanding of power.
42:29The tiny, twitching needle of the telegraph had shown how electricity from a battery could be truly useful.
42:39What's happening here is also something which is much more profound.
42:43It is the coming together of two great forces that previously regarded as utterly separate.
42:50Uncovering the link between two things as disparate as an electric current and a magnetic compass
42:56was one of the greatest achievements of science.
43:00A major step towards a unified concept of energy.
43:07Electricity was the crowd-pleaser.
43:09Flashes, sparks, electric shocks.
43:13Magnetism was altogether more sedate.
43:15Something of interest mainly to navigators.
43:18But when the two came together, they created the science of electromagnetism that would dominate the 19th century.
43:28Electromagnetism not only explained the relationship between electricity and magnetism,
43:34but it would go on to explain the very nature of light.
43:38Of radio waves.
43:41Of X-rays.
43:44And it helped persuade 19th century physicists that they had now discovered all the fundamental laws of nature.
43:55As it turned out, this cozy assumption was somewhat wide of the mark.
44:07At the turn of the 20th century, the discovery of a new element was splashed across front pages all over
44:15the world.
44:27One reason for all the excitement was the way radium behaved.
44:34It spontaneously glowed in the dark
44:39and created ghostly patterns on photographic plates.
44:45It seemed to be creating energy out of nowhere.
45:00Radium's mysterious properties caught the public imagination,
45:04helping to sell a new range of consumer products.
45:12Which was unfortunate, since radium is radioactive.
45:16OK, yes.
45:18Have a look, Mike.
45:20OK, so what am I looking at?
45:21Well, you're looking at a variety of
45:23radioactive consumer products, mostly from the 1920s, produced in the United States.
45:28So this one here, for example, you actually put...
45:32Water in it.
45:33You put water in it?
45:34That is the most famous of the radioactive quack cures, at least in the United States.
45:39Over half a million of these were sold.
45:41This is a similar device, except rather than put the water in it, you would put this in the water.
45:48This is not radioactive now, then?
45:50Or mildly?
45:51Yes, it is radioactive, but it's mild.
45:59It is quite spooky, I must admit.
46:02You can hear it still active all these years later.
46:08So great was the hype that small amounts were put into toothpaste.
46:13Heat pads.
46:15Toys.
46:17Just the name radium was enough to sell a product.
46:22Radium...
46:24Condoms.
46:25Radium condoms.
46:26It's an empty box.
46:30I was looking forward to seeing a radium condom.
46:38The scientists responsible for first isolating radium were Marie Curie and her husband Pierre.
46:48It didn't take them long to recognise its extraordinary potential.
46:55One of the things that stood up in Marie's mind and piqued her curiosity and interest
47:00was the tremendous amount of energy that was being released by the radium.
47:04So they saw radium as an unlimited, or at least potentially unlimited, source of energy, didn't they?
47:09Yes, absolutely.
47:13Just one gram contained enough energy to turn a tonne of freezing water into steam.
47:20While one tonne of radium could do the work of one and a half million tonnes of coal.
47:29The problem facing the scientists was that all they seemed to go completely against the established laws of physics.
47:41Radioactivity presented a serious problem for scientists.
47:44They knew that energy cannot be created or destroyed.
47:47That is the first law of thermodynamics.
47:49But they also knew that these radioactive substances were pouring out huge amounts of energy.
47:56So where was it coming from?
48:05Across the world, scientists had been studying radioactivity intensely.
48:14People notice something peculiar.
48:17That as radioactive substances emit energy, they transform.
48:21They turn into something else.
48:23Radium, for example, becomes lead.
48:26And as they transform, they become lighter.
48:29In other words, as they emit energy, they also lose mass.
48:41The link between energy and mass was eventually explained by Albert Einstein's famous equation.
48:50Energy equals mass times the square of the speed of light.
48:58The energy from the radium wasn't coming from some magical source, but from the mass itself.
49:11People had previously realised that you could describe heat and movement in terms of energy.
49:17Now it seemed you could also describe mass in the same way.
49:21Energy, which hadn't even existed as a concept, was now being used to explain the very nature of matter itself.
49:31In fact, there wasn't much that could not be explained in terms of energy.
49:37Not just steam engines and windmills, but living things.
49:44Stars, even galaxies, all were governed by the laws of energy.
49:53In its quest to understand what power is, science had uncovered secrets which lay at the very heart of the
50:02universe.
50:09The theory encapsulated in E equals MC squared would eventually lead to the release of nuclear energy and the atomic
50:18bomb.
50:21But the consequences of that belong to a different story.
50:26Instead, to complete the story of power, I want to go back to the 19th century.
50:40Back then, theories of energy might have been lighting up men's minds, but they weren't lighting up homes.
50:48Not yet, at any rate.
50:52Most people's domestic lives were largely unaffected by developments in thermodynamics or electromagnetism.
51:00Outside, there were telegraphs and steam trains, but at home, gas lamps, candles and open fires.
51:12What changed our personal relationship with power was the discovery that the link between electricity and magnetism worked both ways.
51:23Ersted had shown that an electric current could act just like a magnet.
51:31British scientist Michael Faraday was the first to demonstrate the opposite, that moving a magnet can produce an electric current.
51:42He used the idea that switching on an electric current could make a magnetised piece of metal move to build
51:48the world's first electric motor.
51:50But he also demonstrated the reverse is true.
51:52Take a magnet, push it through some copper wire, and you produce electricity.
52:02Beautiful, isn't it?
52:04It's called electromagnetic induction, and it was the key to the electric age.
52:17If one could keep the magnet moving fast enough, one could produce an electric current that was continuous.
52:25What was needed was something to keep the magnet moving.
52:39Something like this.
52:42Niagara Falls, one of the most powerful waterfalls in the world.
52:51This is about as close as I can get to the falls, and it really is magnificent.
53:02There's about 150 million litres of water coming over the falls every single minute, and you can really feel the
53:09power.
53:20The challenge lay in finding a way of converting this mass of energy into an altogether more useful form.
53:29Electricity.
53:31Until very recently, I couldn't have stood here because there would have been millions of litres of water just pouring
53:38down here, sweeping everything away.
53:40Up that way, about a kilometre or so, is the power station.
53:54The project began deep underground.
53:58Panels were dug into solid rock by hand to divert some of the water to an electrical generator.
54:06Those taking part sensed it was the dawn of a new age.
54:15When it was first built, it was described as a feat to rival the pyramids, the temples of the Greeks,
54:22the great cathedrals of Europe.
54:24A monument to the scientific age.
54:31And personally, I think they were right.
54:35Because these giant turbines really are the ultimate expression, both of what power is and what power does.
54:45Huge magnets turned by the power of falling water, creating enough electricity to power three-quarters of a million light
54:54bulbs.
54:56But for electricity to become a true commodity, something that could be bought and sold, there was one final barrier
55:03to overcome.
55:06How to get electricity from here in Niagara to the places you'd actually want to sell it.
55:12Cities like Buffalo, 24 miles away, or power-hungry New York, 400 miles away.
55:22The problem was the power loss as the current travelled along the cable.
55:29If you happened to live near a generating plant like this one, then you were fine.
55:34But the further away you moved, the less power you got.
55:38After just a mile, you would begin to notice the difference.
55:43After two miles, well, hardly any current would be getting through at all.
55:50But here at Niagara, this problem was overcome.
55:55Its generators produced what's known as alternating current.
56:00High voltage, low power loss.
56:04Which meant that electricity could finally travel.
56:11When, in 1896, this new form of current was switched on,
56:16it took less than a second to reach Buffalo, over 20 miles away.
56:24In that instant was born the electric age.
56:39The discovery of what power can do for us has transformed our lives,
56:45and set us on a relentless search for new sources of energy.
56:52From deep within the Earth, to inside the smallest atom,
56:56to the Sun itself, our hunger for more power knows few bounds.
57:04Small wonder that our planet alone in the solar system glows in the dark.
57:24But the quest to find out what power is, has had an equally profound effect.
57:32Using the language of mathematics, we have shown energy to be a basic property of the universe.
57:40And it's the coming together of the practical and theoretical approaches to power,
57:46which underpins the modern world.
57:50For a long time, the search for power was led by practical men.
57:55And then the theorists caught up.
57:57And to the plaintive cry,
57:59can we have limitless power, replied a resounding no.
58:04But that search also led the uncovering of fundamental laws of nature,
58:09which now tell us how everything in the universe operates.
58:24Next time, the great puzzle of existence.
58:29What is the secret of life?
58:39And the story of science continues next Tuesday at the same time.
58:43Now, our Junior Apprentice competition continues tomorrow here on BBC HD.
58:47That's at nine.
58:49And coming up next, comedy from The Visit.
58:53The Visit.
58:53The Visit.
58:53www.inunite.org
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