BBC Zero Absoluto A Conquista do Frio Episódio 1

the greatest triumph of civilization is often seen as our mastery of hint yet our conquest of coal is an equally epic journey from dark beginnings to an ultra-cool frontier for centuries code remained a perplexing mystery nobody had any idea what it was much less how to harness its effects yet in the last hundred years cold has transformed the way we live and work imagine homes or supermarkets without fridges and frozen foods or skyscrapers without air-conditioning or hospitals without liquid oxygen we take for granted the technology of cold yet it has enabled us to explore outer space and the inner depths of our brain and as we develop new ultra cold technology to create quantum computers and high-speed networks it may even change the way we think and interact this is the story of how scientists and dreamers over the past four centuries plunged lower and lower down the temperature scale to conquer the cold and rich our lives and attempt to reach the ultimate limit of cold a Holy Grail as elusive as the speed limit of light absolute zero extreme cold has always held a special place in our imagination for thousands of years it seemed like a malevolent force associated with death and darkness cold was an unexplained phenomenon was it a substance a process or some special state of being back in the 17th century no one knew but they certainly felt its effects in the freezing London winters 17th century England was in the middle of what's now called the Little Ice Age it was fantastically cold by modern standards you have to imagine a world lit by fire in which most people are cold most of the time cold would have felt like a real presence a kind of positive agent that was affecting how people felt and that fitted nicely with the most Orthodox received view that natural philosophers had inherited from the Greeks from Aristotle now hundreds of years earlier that there are two agents in the world hot and cold they function symmetrically they can combine or separate back then people felt of the mercy of code this was a time when such natural forces were viewed with or as acts of God so anyone attempting to tamper with cold did so at their peril the first to try was an alchemist Cornelius drebbel on a hot summer's day in 1620 King James the first and his entourage arrived to experience an unearthly event drebbel who was also the court magician had a wager with the king that he could turn summer into winter he would attempt to chill the air in the largest interior space in the British Isles the great hall of Westminster drebbel hoped to shape the king to his core they had a phenomena fertile mind he was an inventor par excellence his whole world was steeped in a world of alchemy of perpetual motion machines of the idea of time space planets rules some gods he was a fervently religious man he was a person for whom nature presented a phenomenal a galaxy of possibilities dr. Andrew [ __ ] lo a chemist with a lifelong fascination for drebbel enjoys his reincarnation as the great court magician like most alchemists treble kept his method secret dr. Shi glow wants to test his ideas on how drebbel created artificial coal when trouble was trying to achieve the lowest temperature possible he knew the ice of course was the freezing point of the coldest you could get normally it would have been aware of the fact through his experience that mixing ice with different salts could get you a colder temperature salts will lower the temperature at which ice melts dr.

Shi Glo thinks drebbel probably used common table salt which gives the biggest temperature drop but salt and ice alone would not be enough to cool down such a large interior drebbel was famous for designing elaborate contraptions a passion shared by dr. Sid Lowe who has an idea for the alchemists machine so here we would have had them a fan which would have been turned over blowing warm air over the cold vessels there and as the air blows over these cold jars we would have had in effect the world's first air conditioning unit but could this really turn summer into winter the idea is to stir it in as well as possible get up in fact in the five seconds that you have to do it dr. [ __ ] low stacks the jars of freezing mixture to create cold corridors for the air to pass through you can feel it's very cold in fact I could feel cold air actually falling on my hands because cold air of course is denser than warm air and one can feel it quite clearly on the fingers the vital question would the gust of warm air become cold Wolffe I can feel certainly a blast of cold air hitting is that second cover was released what temperature if we're on 14 at the moment yes keep it going that's definitely the right direction I think possibly even closer still will give us a better finish nope so how would the king of reacted to his encounter with man-made cold you would have been shocked he wouldn't have known what's happening he could have in fact been wondering whether there's some action of gods or some sort of forces demon demon illogical forces which were in action and he would have left hastily freezing as he did so had drebbel written up his great stunt he might have gone down in history as the inventor of air conditioning yet it would be almost three centuries before this idea eventually took off to advance knowledge and conquer the cold required men with a very different mindset King James's Lord Chancellor Francis Bacon was the first to apply the scientific method to the study of heat and cold he believed it was important to conduct experiments and analyze the results rather than rely on the established wisdom of the Ancients for Francis Bacon heat and cold turn out to be right at the center of his worldview one way of understanding why that so is think why heat and cold matter to human beings they really matter in the 17th century for two reasons one is the weather and one is disease there was after all an obvious tension in everyday experience between the healthy effects of warmth and healthy effects of cold warmth made you healthy because it stopped you radiating away the vital spirits within you but cold obviously had crucial effects against death as well it could preserve things for immensely long times and maybe it could preserve Francis Bacon body two vacant rarely carried out experiments himself but his one foray into the preservative effects of the cold had disastrous consequences he took a freshly killed chicken and stuffed it full of ice and snow to investigate how much longer the chicken meats might stay fresh he was impressed by the results the chicken did remain fresh for many days unfortunately during the process of exposing his own body to the cold he caught pneumonia as bacon Lay Dying it dawned on him that his fascination with the cold was going to cost him his life the irony tragedy of that rather sad experiment didn't dissuade his followers from doing more experiments on ice and snow and it's vital or preservative effects the men who followed beggin were really convinced that if we could understand the way in which motion cold and heat fitted together we could save ourselves from disease we could unlock the mysteries of the universe this fundamental question what is cold haunted Robert Boyle who was born the year after bacon died the son of the Earl of cork a wealthy nobleman boiled used his fortune to build an extensive laboratory Boyle is famous for his experiments on the nature of air but he also became the first master of cold believing it to be an important but neglected subject he carried out hundreds of experiments he worked through very systematically a series of ideas about what cold is does it come from the air does it come from the absence of light is it that there are strange so-called Frigga rific cold making particles the dominant view certainly in Boyle's lifetime the view that he set out to attack is that cold is a primordial substance that when bodies get colder they're sucking in this primordial cold and as they get warmer they expel it Boyle thought that was wrong and he did experiments to show that it was wrong Boyle was curious about the way water expanded when it turned to ice he wondered whether the increase in volume was accompanied by an increase in weight they carefully weighed a barrel of water and took it outside in the snow leaving it to freeze overnight Boyle reasoned that if once the water turned to ice the barrel weighed more then perhaps cold was a substance after all but when they reweighed the barrel they discovered it weighed exactly the same so what must be happening Boyle guessed was that the particles of water were moving further apart that was the expansion not some substance flowing into the barrel from outside Boyle was becoming increasingly convinced that cold was not a substance but something that was happening to the particles and began to think back to his earlier experiments with his air pump Boyle's idea was that the air trapped in this glass container is springy it's elastic as you try and compress it it resists now this is very closely linked in Boyle's program to the way he studies heat and cold because his idea was that as substances like the air get warmer they tend to expand it's as though the little particles little Springs out of which he imagined the chair particle is made gradually unwinding so they take up more space and they expand Boyle's conclusion here was that heat is a form of motion of a particular kind and that as bodies cool down they move less and less Boyle's longest published book was on the cold yet he found its study troublesome and full of hardships declaring that he felt like a physician trying to work in a remote country without the benefit of instruments or medicines to properly explore this country of the cold boy lamented the lack of a vital to an accurate thermometer it was not until the mid 17th century that glassblowers in Florence began to produce accurately calibrated thermometers now it became possible to measure degrees of hot and cold because rather than mercury they used alcohol which is much lighter they made thermometers that was sometimes several meters long and were often wound into spirals but there was still one major problem with all thermometers the lack of a universally agreed temperature scale there are all kinds of different ways of trying to stick numbers to this degrees of hot and cold and they on the whole didn't agree with each other at all so one guy in Florence makes one kind of the moment or another guy in London makes a different kind and they just don't even have the same scale and so there was a lot of problem in trying to standardize the monitors imagine that you want to make a scale of temperature what do you do well the obvious thing to do and this was well understood by instrument makers and experimenters in the 17th and 18th century is to try and find something in nature which you know always has the same temperature and make that your fixed point a better strategy even is to find two such phenomena in nature and then you have a lower fixed point like something rather cold and an upper fixed point something rather warm and divide the degrees of temperature between and to say a hundred convenient bite-sized chunks the problem however was to find to define a phenomenon whose temperature you guessed was fixed so for the lower fixed point you might choose the temperature of ice just as its melting and then there's an almost indefinite range of possible candidates for your upper fixed point um is it Newton for example work rather hard on constructing what he called a scale of heat he for example defined the temperature which a human can only just tolerate if they plunge their hand into warm water it could be the normal human underarm the temperature of the human blood the temperature of wax just as its melting the first temperature scale to be widely adopted was devised by Daniel Fahrenheit an accomplished instrument maker who made thermometers for doctors in Holland he used a mixture of ice water and salt for his zero degrees ice melting in water at 32 degrees and freeze up a fixed point the temperature of the human body at 96 degrees which is close to the modern value one of the things that Fahrenheit was able to achieve was to make the moment as quite small and that he did by using mercury as opposed to alcohol or air which other people had used and because mercury the moment there's a compact clearly if you're trying to use it for clinical purposes you don't want some big things sticking out of the patient so the fact that he could make them small and convenient that seems to be what made Fahrenheit so famous and so influential it was a Swedish astronomer and of Celsius who came up with the idea of dividing the scale into a hundred divisions the original scale used by Celsius was upside-down so he had the boiling point of water as zero and the freezing point has 100 with numbers just continuing to increase as we go below freezing and this is another little mystery in the history of the thermometer that we just don't know for sure what was he thinking when he labeled it this way and it was the botanist Linnaeus um who was then the president of the Swedish Academy who after a few years said well we need to stop this nonsense and inverted the scale to give us what we now call Celsius scale today a question nobody thought to ask when devising temperature scales was how low can you go is there an absolute lower limit of temperature the idea that there might be would become a turning point in the history of coal the story begins with the French physicist Guillaume Amato he was doing experiments are heating and cooling bodies of air to see how they expand and contract we're now going to put ice around our bulb and see what happened he was noticing that well when you cool a body of air the volume or the pressure would go down and he speculated well what would happen if we just kept cooling it by plotting temperature against pressure a Montone saw that as the temperature dropped so did the pressure and this gave him an extraordinary idea amontons started to consider the possibility what would happen if you projected this line back until the pressure was zero and this was the first time in this course of history that people have actually considered the concept of an absolute zero of temperature zero pressure zero temperature it was quite a revolutionary idea when you think about it because you wouldn't just think that temperature has a limit of a lower bound or zero because in the upper end it can go on forever we think until it's hotter and hotter and hotter but somehow maybe there's a zero point where this all begins so you could actually give a calculation of where this on zero point would be a Montone didn't do that calculation himself or some other people did later on and when you do it you get a value that's actually not that far from the modern value of roughly minus 273 centigrade in one stroke a montón had realized that although temperatures might go on rising forever they could only fall as far as this absolute point for him this was a theoretical limit not a goal to attempt to reach before scientists could venture towards this zero point far beyond the coldest temperatures on earth they needed to resolve a fundamental question by now for most scientists the penny had dropped the cold was simply the absence of heat but what was actually happening as substances warmed or cooled was still hotly debated the argument of men like a mantra relied completely on the idea that heat is a form of motion and that particles move more and more closely together as the substance in which they're in get gets cooler and cooler unfortunately the science of cold was about to suffer a serious setback the idea that cooling was caused by particles slowed down began to go out of fashion at the end of the 18th century a rival theory of heat and cold emerged that was tantalizingly appealing but completely wrong it was called the caloric theory and its principle advocate was the great French chemist Antoine Lavoisier like most scientists of the time Lavoisier's a rich aristocrats who funded his own research he and his wife Madame Lavoisier who assisted with his experiments even commissioned the celebrated painter David to paint their portrait Lavoisier's out experiments to support the erroneous idea that heat was a substance a weightless fluid that he called calorie he thought in the solid state of matter molecules were just packed closing together and when you added more and more calorie to this the cleric would insinuate itself between these particles of matter and loosened them up so the basic notion was the cleric was this fluid that was as he put itself repulsive it just tended to break things apart from each other and that's his basic notion of he that the cold is just the absence of caloric or the relative lack of caloric Lavoisier's an apparatus to measure calorie which he called a calorimeter he packed the outer compartment with ice inside he conducted experiments that generated heat sometimes from chemical reactions sometimes from animals to determine how much calorie was released he collected the water from the melting ice and waded to calculate the amount of calorie generated from each source I think the most striking thing about lebretia is that he sees caloric as a substance which is exactly comparable with ordinary matter to the point that he includes glory in his list of the elements it's very easy to talk about the quantity of heat and to think of it as a fluid whereas to talk about the quantity of heat and to think of it as a vibration of the particles of matter which was the other alternative that's much more difficult conceptually it's a very hard model to refute because if you can accept that there's a substance that doesn't have any weight indeed for Lavoisier a heat calorie is an element it's an element like oxygen or nitrogen oxygen gas is made of oxygen plus calorie you can take the calorie Kawai presumably the oxygen might liquefy so it's a very hard model to shift because it explains so much and indeed Lavoisier's chemistry was so otherwise extraordinarily successful however Lavoisier's story about calorie was soon undermined there was one man who was convinced Lavoisier's wrong and was determined to destroy the calorie theory his name was Count Romford count Rumford had a colorful past he was born in America spied for the British during the Revolution and after being forced into exile became an influential government minister in Bavaria among his varied responsibilities was the artillery works and it was here in the 1790s that he began to think about how he might be able to disprove the caloric theory using cannon boring Rumford had noticed that the friction from boring out a cannon barrel generated a lot of heat he decided to carry out experiments to measure how much he adapted the machine to produce even more heat by installing a blunt borer that had one end submerged in a jacket of water as the cannon turned against the Bora the temperature of the water increased and eventually boiled the longer he bored the more heat was produced to Rumford what this showed was that heat must be a form of motion and heat is not a substance because you could generate indefinitely large amounts of heat simply by turning the cannon despite count Rumford 'he's best efforts Lavoisier's calorie theory remained dominant until the end of the 18th century his prestige as a scientist meant that few dared challenge his ideas sadly this did not protect him from the revolutionary turmoil in France which is about to interrupt his research at the height of the reign of terror love was a was arrested and eventually guillotine the reason he was guillotine was not because of his science but because he helped run the privatized income tax service of the French state and there's nothing more unpopular even in France than a privatized tax collector once he was guillotine his wife left France and eventually met Rumford when he moved to Western Europe in the early 1800s Rumford then married her so he'd married the widow of the man who'd founded the theory that he'd destroyed the marriage was short-lived after a tormented year Rumford left Madame Lavoisier and devoted the rest of his life to his first love science it would be nearly 50 years before his theory of heat and cold was finally accepted a founder of the Royal Institution Rumford continued to support the pursuit of science and it was here that the next major breakthrough in the conquest of cold would occur Michael Faraday who later became famous for his work on electricity and magnetism unwittingly carried out an experiment that would begin the long descent towards absolute zero he was asked to explore the properties of a newly discovered pungent gas called chlorine this experiment was potentially explosive which is perhaps why it was left to Faraday and perhaps also why dr.

Andrew Shidler is curious to repeat it today we are about to undertake an exceedingly dangerous experiment in which Michael Faraday in 1823 heated this substance here the hydrate of chlorine in a sealed tube is that sim that sold Andrew that's absolutely brilliant in the original experiment Faraday took the sealed tube and heated the end containing the crystals he put the other end in an ice bath soon he noticed yellow chlorine gas been given off because the gas is being produced pressures building up but because this sight is so very cold hopefully what we'll see is some tiny oily droplets of chlorine liquid chlorine being produced it's the pressure which is causing this right this is where it starts to get dangerous so if you now take a few steps back when Faraday did the experiment a visitor dr.