Now it's time to come back to all that cool technology from the early 18 hundreds.

How does steam work?

How can we quantify hot air or mathematically described the motion of a piston or the heat from the barrel of a cannon?

Thermodynamics or the physics of heat, temperature, energy and work doesn't really have a Darwin and Wallace.

It's a lot messier.

Scientists were confused about the basic concepts of heat transfer.

How stuff heats up, cools down and temperature.

And for most of human history, they didn't even have a good way to measure temperature.

Galileo and Newton made attempts, but it wasn't until the early 17 hundreds that Gabriel Fahrenheit finally nailed it.

But that still doesn't explain how and why things heat up.

Ah, lot of people tried to crack the physics behind these phenomena, like chemist Antoine Lavoie, see a remember him from Episode 18.

He used the caloric theory, which explained he transfer as Anethe ER, or colorless fluid that migrated from a body at a higher temperature toe one at a lower temperature.

This made sense to love Aussie A when he was upending chemistry, but it was wrong.

In fact, either was the explanation for many unknown phenomenon in the 18th century, and there were a lot of conflicting ether theories throughout the entire 18 hundreds.

Ah, large number of chemists, physicists, engineers and mathematicians across the world worked out the not wrong physics of heat and motion.

One of the first was American physicist Benjamin Thompson, better known as Count Rumford.

We've actually met Rumford before he married love.

WASI is scientifically inclined, Widow Marie.

So yes, Marie Lavoie see a helped develop the modern sciences of both chemistry and the physics of heat and energy.

Romford conducted a lot of experiments in the barrels of cannons, like how to measure and insulate against heat.

He noticed that certain materials insulated better than others in that air, seemed to be involved in the transfer of heat and concluded that air is a great insulated.

He then moved on to liquids and concluded that they are also great Insulate ear's all of them which, you know water boils so kind of problematic science, but he kept going.

In his experiments, Romford noticed that something other than the caloric ether was heating up various substances.

So he devised an experiment which showed that the boring of a cannon, like the hollowing out of the barrel released heat.

Basically, he just created a cannon barrel by drilling a hole in a long piece of metal for over two hours.

But this was the twist Rummy did this underwater, which eventually caused the water to boil.

He wasn't the invisible fluid part of a chemical reaction but simple mechanical motion.

In some ways, this result should have been obvious to anyone who had observed friction.

But Romford brought it back to scientific attention.

How is heat created in transferred epistemological needed to catch up with technique and ether needed to be replaced by a new science.

Science picked up steam with the invention of the steam engine.

After engineers like James Watt designed ways of producing steam and directing it to move machines, scientists tried to improve the efficiency of these systems.

Steam engines were not an example of basic research applied to the real world.

The cool new tech came first, later, propelling a lot of useful research into how heat and energy function.

French physicist and engineer Nicolas A.

De Carnot grew up during the Napoleonic Wars.

He believed that steam engine efficiency was the key to helping France become a glorious empire.

Carlos worked with steam engines, led him to think a lot about thermodynamics in an engine cycle.

Parts of the system moved through different states of energy and finally return to the initial state.

Inventors were thinking up all sorts of great applications for engines like locomotives, but no one could mathematically explain what was going on.

Carnot figured out what became known as De Carnot Cycle, or the science of what happens Inside heat producing engines.

The car No Cycle describes the upper limit of the efficiency of a model thermodynamic system or a system where heat moves around within set boundaries.

In 18 24 Carnot published the paper Reflections on the Motive.

Power of Fire and on Machines fitted to develop.

That power is contained, although not in the same words we would use today.

The second law of thermodynamics, which states that the total entropy of a closed system can never decrease on Lee, stay steady or increase heat can't randomly flow from a colder point to a hotter one.

This is just one way to express the universal principle of entropy or the state of disorder in a system.

But don't get too philosophical about chaos.

Entropy is just a variable that you can calculate with the right math.

Carnot didn't quite know what he had going.

He presented his findings in terms of the reigning caloric theory, and then he died of cholera at the tragically young age of 36.

Many other physicists around car knows time realized that heat, like chemical reactions and motion, aren't merely very complex phenomenon on their own.

They're all part of a larger, more complex system, and they interact with each other.

The 18 forties.

Several scientists independently discovered what we now confusingly called the first law of thermodynamics, or the conservation of energy.

Energy can change from one form to another, but energy is not lost.

It has to go somewhere Energy and Cole, for example, is released into heat and light as fire, and the first law is not just a metaphysical idea.

It can be quantified.

The whole point of thermodynamics is to put numbers toe all of the complex motions and reactions that move energy from one form to another to find the fixed exchange rates between states of energy.

In the 18 forties, English physicist James Jewell and German doctor Julius von Mayer independently figured out that he transfer and mechanical work were different forms of the same thing, which we now call energy transfer thought bubble.

Give us an introduction.

This was such a big deal.

Heat is just motion and vice versa, just like Ronnie's cannon experiment showed.

In fact, today, the Jewell is the unit of energy.

But alas, neither of their mechanical theories of heat was accepted.

At the time Jule experimented with batteries and electromagnets, trying to determine the relationship between heat and motion.

He concluded that the heat needed to increase the temperature of a pound of water by one degree of Fahrenheit.

Scale was equal to a mechanical forest capable of raising £838 to the perpendicular height of one foot.

Today we would say that's about four jewels per calorie of work, Jewell told this to the other members of the British Association for the Advancement of Science in 18 43 who were like, Congrats, bro.

You've just invented warm water, I guess.

Undaunted, Jule set out to prove his theory.

Conducting experiments on his honeymoon, Jule put a dynamo in water and measured it experimentally, confirming his mechanical theory.

He forced water through a perforated cylinder, measuring the very slight degree to which the water heated up and found that his mechanical heating up energy was the same as his electrical.

Heating up about four jewels.

Or, as he said, wherever mechanical force is expended on exact equivalent of heat is always obtained.

And then, in 18 45 Jule dropped on the mechanical equivalent of heat, in which he detailed his experiments using, AH, falling weight that is gravity to move a paddle wheel inside an insulated barrel of water.

In order to heat it up again, he measured the energy involved and found around four jewels.

Jule finally began to get his peers attention, but caloric theory still reigned.

Thanks, thought bubble.

Julius von Mayer, on the other hand, tried to publish his ideas, but he was rejected, so he attempted suicide but only broke his legs.

He was declared insane and locked up in an asylum for a long time mayor was overlooked is the independent co discoverer of the mechanical equivalents of heat energy.

Jewell got all the credit, although Jewell did give Mayor a shout out in a paper in 18 50.

Mayor also hypothesized that plants convert light into chemical energy or photosynthesize way ahead of his time.

Meanwhile, Scottish physicist William Thompson, better known as Lord Calvin, heard Jule talk at the British Association in 18 47 and wanted more evidence.

Lord Kelvin was also a big fan of car knows, but he wanted to push his theories farther, so he tried to reconcile Car Knows work as explained by caloric ether with jewels.

Lord Calvin is usually credited with coining the term thermodynamics in 18 54.

Here's his definition.

Thermodynamics is the subject of the relation of heat to forces acting between contiguous parts of bodies and the relation of heat to electrical agency.

Ultimately, Lord Kelvin rejected caloric theory, and he teamed up with Jules.

Kelvin worked on many aspects of physics and other sciences.

Today, he's probably best known as the dude who worked out the science of absolute temperatures, which are now measured in the unit called Kelvin In the 18 fifties and sixties, German physicist Rudolph Classy use figured out that there were actually two distinct laws at work in car knows most famous paper, and they contradict each other.

Close use restated the first and second laws of thermodynamics, removing the contradiction his version of the second law.

Heat can never pass from a colder to a warmer body without some other change connected, therewith occurring at the same time in 18 65 class use also gave the first mathematical description of entropy and named it, and this paper ended with the brilliantly simple summary of the first and second laws of thermodynamics.

The energy of the universe is constant.

The entropy of the universe tends to a maximum thermodynamics, deeply united chemistry and physics in the way that Newton's Principia had united mathematics and astronomy.

Suddenly, experiments and theories that looked very different on the surface were joined at a basic level.

Thermodynamic concepts from the studies of heat engines were all applied to chemical reactions.

Entropy proved very useful idea in many disciplines, including statistics.

So at the end of the 19th century, if you were a fan of thermodynamics, you might say that the question of what is stuff was close to being solved.

But you'd be wrong because of Einstein.

Wait for him, but also because the history of thermodynamics was a hot mess.

Pond definitely intended.

This history is often presented as an orderly progression of ideas, each building on the foundation of laws created by earlier investigators.

But that's not quite true after all.

What we now call the second Law of thermodynamics preceded the first by more than 25 years, not super orderly.

And then there were long periods where invalid ideas were tenaciously held in the face of decisive evidence of their falsity.

In other cases, as with genetics, lots of scientists simultaneously adopted a whole new block of theory and built upon it.

Next time, sparks will fly as we meet another gang of 19th century physicists and engineers.

The pioneers of electricity crash course History of Science is filmed on the Dr Cheryl Seek any studio in Missoula, Montana, and it's made with the help of all of these nice people, and our animation team is thought Cafe crash courses, a complexly production if you want to keep imagining the world complexly with us.

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