In the
history of science, the
history of heat traces its origins to the first
hominids to make
fire and to speculate on its operation and meaning to modern day
particle physicists who study the sub-atomic nature of
heat. In short, the phenomenon of heat and definition of what it's evolved from mythological theories of
fire, to
heat, to
terra pinguis,
phlogiston, to
fire air, to
caloric, to the
theory of heat, to the
mechanical equivalent of heat, to
thermo-dynamics (sometimes called
energetics) to
thermodynamics. The history of heat, then, is a precursor for developments and theories in the
history of thermodynamics.
Early views
The ancients viewed heat as that related to
fire. The Egyptians in 3000 BC viewed heat as related to origin mythologies. One example, is the theory of the
Ogdoad, or the “primordial forces”, from which all was formed. These were the elements of
chaos, numbered in eight, that existed before the creation of the sun.
The first to have put forward a semblance of a theory on heat was the
Greek philosopher Heraclitus who lived around 500 BC in the city of
Ephesus in
Ionia,
Asia Minor. He became famous as the "flux and fire" philosopher for his proverbial utterance: "All things are flowing." Heraclitus argued that the three
principal elements in nature were fire, earth, and water. Of these three, however, fire is assigned as the central element controlling and modifying the other two. The universe was postulated to be in a continuous state of flux or permanent condition of change as a result of transformations of fire. Heraclitus summarized his philosophy as: "All things are an exchange for fire."
As early as 460 BC
Hippocrates, the father of medicine, postulated that:
The hypothesis that heat is a form of motion was proposed initially in the 12th century. Around 1600, the English philosopher and scientist
Francis Bacon surmised that:
This echoed the mid-17th century view of English scientist
Robert Hooke, who stated:
18th century
In 1761, Scottish chemist
Joseph Black discovered that
ice absorbs heat without changing
temperature when
melting. From this he concluded that the heat must have combined with the ice particles and become
latent. Between 1759 and 1763 he evolved that theory of "
latent heat" on which his scientific fame chiefly rests, and also showed that different substances have different specific heats.
James Watt, who later invented the
Watt engine, was Black's pupil and assistant.
In this direction, the ability to be able to use heat transfer to generate work allowed the invention and development of the
steam engine by people such as
Thomas Newcomen and
James Watt. In addition, in 1797 a cannon manufacturer Sir
Benjamin Thompson, Count Rumford, demonstrated through the use of friction it was possible to convert work to heat. To do this, he designed a specially shaped cannon barrel, thoroughly insulated against heat loss, then replaced the sharp boring tool with a dull drill bit, and immersed the front part of the gun in a tank full of water. Using this setup, to the amazement of his onlookers, he made cold water boil in two-and-half-hours time, without the use of fire.
Several theories on the nature of heat were developed. In the 17th century,
Johann Becher proposed that heat was associated with an undetectable material called
phlogiston that was driven out of a substance when it was burnt. This was finally refuted by
Lavosier demonstrating the importance of oxygen in burning in 1783. He proposed instead the
caloric theory which saw heat as a type of weightless, invisible fluid that moved when out of equilibrium. It was this theory used in 1824 by the French engineer
Sadi Carnot when he published
Reflections on the Motive Power of Fire. He set forth the importance of heat transfer: "production of motive power is due not to an actual consumption of caloric, but to its transportation from a warm body to a cold body, for example to its re-establishment of equilibrium." According to Carnot, this principle applies to any machine set in motion by heat.
Another theory was the
kinetic theory of gases, the basis of which was laid out in 1738 by the Swiss physician and mathematician
Daniel Bernoulli in his
Hydrodynamica. In this work, Bernoulli first proposed that gases consist of great numbers of molecules moving in all directions, that their impact on a surface causes the gas pressure that we feel. The internal energy of a substance is then the sum of the kinetic energy associated with each molecule, and heat transfer occurs from regions with energetic molecules, and so high internal energy, to those with less energetic molecules, and so lower internal energy.
19th century
The work of
Joule and
Mayer demonstrated that heat and work were interchangeable, and led to the statement of the principle of the
conservation of energy by
Hermann von Helmholtz in 1847.
Clausius demonstrated in 1850 that caloric theory could be reconciled with kinetic theory provided that the conservation of energy was employed rather than the movement of a substance, and stated the
First Law of Thermodynamics.
In 1851,
William Thomson outlined the essentially modern-view, as based on recent experiments by those such as
James Joule on the dynamical
theory of heat, that:
On this view, he argued that we must "perceive that there must be an
equivalence between mechanical work and heat, as between
cause and effect.”
20th century
At the turn of the 20th century, the discovery of the
electron (1897), the
photon (1905), the
nucleus (1909) and assembly of
quantum electrodynamics (1930s) as the science that studies the operation of these
fundamental particles the definition of heat became more complicated. Heat in modern terms, is generally defined as a type of energy transferred due to a temperature difference or that generated by friction, etc.
What exactly constitutes energy in
particle physics terms, however, is a blurry picture. All
elementary particles in the universe, according to the
standard model are either
fermions, for example particles with ½-spin, or
bosons, for example particles with integral spin. In this view, energy is loosely defined as a spin-1
Gauge boson. Thus, heat, in the predominant
standard temperature and pressure sense, is related to
photon movement and the kinetic effects of this movement.
External results
Click here for more details on History Of Heat
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://history_of_heat.totallyexplained.com">History of heat Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
We see you're using Internet Explorer. Try Firefox, we think you'll like it better.
· Firefox blocks pop-up windows.
· It stops viruses and spyware.
· It keeps Microsoft from controlling the future of the internet.
Click the button on the right to download Firefox. It's free.