Transcript Blue and Grey

New Ideas
The geocentric model was nearly universally accepted until 1543 when
Nicolaus Copernicus published his book entitled De revolutionibus
orbium coelestium and was widely accepted into the next century. At
around the same time, the findings of Vesalius corrected the previous
anatomical teachings of Galen of Pergamon (129 - 217 AD), which were
based upon the dissection of animals even though they were supposed to
be a guide to the human body.
Advances in Anatomy
Andreas Vesalius (1514–1564) was an author of one of the most
influential books on human anatomy, De humani corporis
fabrica, also in 1543.
French surgeon Ambroise Paré (c.1510–1590) is considered as
one of the fathers of surgery; he was leader in surgical
techniques and battlefield medicine, especially the treatment of
wounds.
Partly based on the works by the Italian surgeon and anatomist
Matteo Realdo Colombo (c. 1516 - 1559), the anatomist William
Harvey (1578–1657) described the circulatory system.
Herman Boerhaave (1668–1738) is sometimes referred to as a
"father of physiology" due to his exemplary teaching in Leiden
and textbook 'Institutiones medicae' (1708).
Circulatory System
William Harvey (1 April 1578 – 3 June 1657) was an English
physician who was the first person to describe completely and in
detail the systemic circulation and properties of blood being
pumped to the body by the heart.
Before Harvey, Galen of Pergamon incompletely perceived the
function of the heart, believing it a "productor of heat", while the
function of its affluents, the arteries, was that of cooling the
blood as the lungs "...fanned and cooled the heart itself".
Modern Science
Pierre Vernier (1580–1637) was inventor and eponym of
the vernier scale used in measuring devices.
Evangelista Torricelli (1608 – 1647) was an Italian
physicist and mathematician. After Galileo's death in
1642, he succeed Galileo as the professor of
mathematics in the University of Pisa. Torricelli's chief
invention was the mercury barometer, which arose from
solving a practical problem. Pump makers of the Grand
Duke of Tuscany attempted to raise water to a height of
12 meters or more, but found that 10 meters was the
limit with a suction pump. In 1643 he created a tube
approximately one meter long, sealed at the top, filled it
with mercury, and set it vertically into a basin of
mercury. Torricelli also discovered Torricelli's Law,
regarding the speed of a fluid flowing out of an opening,
which was later shown to be a particular case of
Bernoulli's principle.
The Slide Rule
Although Franciscus Vieta (1540–1603) gave the first notation of
modern algebra, John Napier (1550–1617) invented logarithms,
and Edmund Gunter (1581–1626) created the logarithmic
scales (lines, or rules) upon which slide rules are based. It was
William Oughtred (1575–1660) who first used two such scales
sliding by one another to perform direct multiplication and
division; and thus is credited as the inventor of the slide rule in
1622.
Invention of the mechanical calculator
Blaise Pascal (1623–1662) invented the mechanical calculator in
1642. The introduction of his Pascaline in 1645 launched the
development of mechanical calculators first in Europe and then
all over the world.
He also made important contributions to the study of fluid and
clarified the concepts of pressure and vacuum by generalizing
the work of Evangelista Torricelli. He wrote a significant treatise
on the subject of projective geometry at the age of sixteen, and
later corresponded with Pierre de Fermat (1601–1665) on
probability theory, strongly influencing the development of
modern economics and social science.
Steam Engine
Denis Papin (1647–1712), a French-born
physicist, mathematician and inventor, was
best known for his pioneering invention of
the steam digester, the forerunner of the
steam engine and the pressure cooker.
Abraham Darby (1678–1717) developed a
method of producing high-grade iron in a
blast furnace fuelled by coke rather than
charcoal. This was a major step forward in
the production of iron as a raw material for
the Industrial Revolution.
Thomas Newcomen (1664–1729) perfected a
practical steam engine for pumping water,
the
Newcomen
steam
engine.
Consequently, he can be regarded as a
forefather of the Industrial Revolution.
A Revolution
Newcomen engines were used throughout
Britain and Europe, principally to pump
water out of mines, starting in the early 18th
century. James Watt's later engine was an
improved version. Although Watt is far more
famous today, Newcomen rightly deserves
the first credit for the widespread
introduction of steam power.
Sadi Carnot
Nicolas Léonard Sadi Carnot (1796 – 1832)
was a French physicist who, in his 1824
Reflections on the Motive Power of Fire,
gave the first successful theoretical account
of heat engines, now known as the Carnot
cycle, thereby laying the foundations of the
second law of thermodynamics. He is often
described
as
the
"Father
of
thermodynamics", being responsible for
such concepts as Carnot efficiency, Carnot
theorem, Carnot heat engine, and others.
Carnot’s book apparently received very little attention from his
contemporaries at first. The work only began to have a real impact when
modernised by Émile Clapeyron, in 1834 and then further elaborated upon
by Clausius and Kelvin, who together derived from it the notion of entropy
and the second law of thermodynamics.
History of Entropy
The concept of entropy developed in response to the observation
that a certain amount of functional energy released from
combustion reactions is always lost to dissipation or friction and
is thus not transformed into useful work. Early heat-powered
engines such as Thomas Savery's (1698), the Newcomen
engine (1712) and the Cugnot steam tricycle (1769) were
inefficient, converting less than two percent of the input energy
into useful work output; a great deal of useful energy was
dissipated or lost into what seemed like a state of immeasurable
randomness. Over the next two centuries, physicists
investigated this puzzle of lost energy; the result was the
concept of entropy.
Lazare Carnot
In 1803, mathematician Lazare Carnot (1753 - 1823) published a work
entitled Fundamental Principles of Equilibrium and Movement. This
work includes a discussion on the efficiency of fundamental
machines, i.e. pulleys and inclined planes. Lazare Carnot saw through
all the details of the mechanisms to develop a general discussion on
the conservation of mechanical energy. Over the next three decades,
Lazare Carnot’s theorem was taken as a statement that in any
machine the accelerations and shocks of the moving parts all
represent losses of moment of activity, i.e. the useful work done. From
this Lazare drew the inference that perpetual motion was impossible.
This loss of moment of activity was the first-ever rudimentary
statement of the second law of thermodynamics and the concept of
'transformation-energy' or entropy, i.e. energy lost to dissipation and
friction.
Sadi Carnot
Lazare Carnot died in exile in 1823. During the following year Lazare’s
son Sadi Carnot, having graduated from the École Polytechnique
training school for engineers, wrote the Reflections on the Motive
Power of Fire. In this paper, Sadi visualized an ideal engine in which
the heat of caloric converted into work could be reinstated by
reversing the motion of the cycle, a concept subsequently known as
thermodynamic reversibility. Building on his father's work, Sadi
postulated the concept that “some caloric is always lost”, not being
converted to mechanical work. Hence any real heat engine could not
realize the Carnot cycle's reversibility and was condemned to be less
efficient. This lost caloric was a precursory form of entropy loss as we
now know it. Though formulated in terms of caloric, rather than
entropy, this was an early insight into the second law of
thermodynamics.
Caloric Theory
The caloric theory was introduced by Antoine Lavoisier. Lavoisier
developed the explanation of combustion in terms of oxygen in the
1770s. In 1783, Lavoisier proposed a 'subtle fluid' called caloric as the
substance of heat. According to this theory, the quantity of this
substance is constant throughout the universe, and it flows from
warmer to colder bodies. Indeed, Lavoisier was one of the first to use
a calorimeter to measure the heat changes during chemical reaction.
Since heat was a material substance in caloric theory, and therefore
could neither be created nor destroyed, conservation of heat was a
central assumption.The introduction of the Caloric theory was also
influenced by the experiments of Joseph Black related to the thermal
properties of materials. Besides the caloric theory, another theory
existed in the late eighteenth century that could explain the
phenomena of heat: the kinetic theory. The two theories were
considered to be equivalent at the time, but kinetic theory was the
more modern one, as it used a few ideas from atomic theory and
could explain both combustion and calorimetry.
Later Developments
In 1798, Count Rumford published a report on his investigation of the
heat produced while manufacturing cannons. He had found that
boring a cannon repeatedly does not result in a loss of its ability to
produce heat, and therefore no loss of caloric. This suggested that
caloric could not be a conserved "substance".
Rumford's experiment inspired the work of James Prescott Joule (1818 –
1889) and others. Joule was an English physicist and brewer. Joule
studied the nature of heat, and discovered its relationship to
mechanical work. This led to the theory of conservation of energy,
which led to the development of the first law of thermodynamics. The
SI derived unit of energy, the joule, is named after him.
First Law of Thermodynamics
The first explicit statement of the first law of thermodynamics was
given by Rudolf Clausius in 1850:
"There is a state function E, called ‘energy’, whose differential
equals the work exchanged with the surroundings during an
adiabatic process."
Rudolf Clausius (1822 – 1888), was a German
physicist and mathematician and is considered
one of the central founders of the science of
thermodynamics. By his restatement of Sadi
Carnot's principle known as the Carnot cycle, he
put the theory of heat on a truer and sounder
basis. In 1865 he introduced the concept of
entropy.
Second Law of Thermodynamics
The second law of thermodynamics may be expressed in many
specific ways, the most prominent classical statements being
the original statement by Rudolph Clausius (1850), the
formulation by Lord Kelvin (1851), and the definition in
axiomatic thermodynamics by Constantin Carathéodory (1909).
These statements cast the law in general physical terms citing
the impossibility of certain processes. They have been shown to
be equivalent.
Clausius statement: No process is possible whose sole result is
the transfer of heat from a body of lower temperature to a body
of higher temperature.
Kelvin statement: No process is possible in which the sole result is
the absorption of heat from a reservoir and its complete
conversion into work.
History of Entropy
In 1865, Clausius gave irreversible heat loss in cyclic process a
name:
“I propose to name the quantity S the entropy of the system, after
the Greek word, the transformation content. I have deliberately
chosen the word entropy to be as similar as possible to the word
energy: the two quantities to be named by these words are so
closely related in physical significance that a certain similarity in
their names appears to be appropriate.”
Although Clausius did not specify why he chose the symbol "S" to
represent entropy, it is arguable that Clausius chose "S" in
honor of Sadi Carnot, to whose 1824 article Clausius devoted
over 15 years of work and research. On the first page of his
original 1850 article "On the Motive Power of Heat, and on the
Laws which can be Deduced from it for the Theory of Heat",
Clausius calls Carnot the most important of the researchers in
the theory of heat.
Later developments
In 1876, physicist J. Willard Gibbs, building on the work of
Clausius, Hermann von Helmholtz and others, proposed that the
measurement of "available energy" ΔG in a thermodynamic
system could be mathematically accounted for by subtracting
the "energy loss" TΔS from total energy change of the system
ΔH. These concepts were further developed by James Clerk
Maxwell.
Josiah Willard Gibbs
Josiah Willard Gibbs (1839 – 1903) was an
American theoretical physicist, chemist, and
mathematician. He devised much of the
theoretical
foundation
for
chemical
thermodynamics as well as physical chemistry.
Yale University awarded Gibbs the first
American Ph.D. in engineering in 1863, and he
spent his entire career at Yale.
In 1901, Gibbs was awarded the highest possible
honor granted by the international scientific
community of his day, granted to only one
scientist each year: the Copley Medal of the
Royal Society of London, for his greatest
contribution of being "the first to apply the
second law of thermodynamics to the
exhaustive discussion of the relation between
chemical, electrical, and thermal energy and
capacity for external work."
Later developments
In 1876, physicist J. Willard Gibbs, building on the work of
Clausius, Hermann von Helmholtz and others, proposed that the
measurement of "available energy" ΔG in a thermodynamic
system could be mathematically accounted for by subtracting
the "energy loss" TΔS from total energy change of the system
ΔH. These concepts were further developed by James Clerk
Maxwell.
Hermann von Helmholtz
Hermann von Helmholtz (1821 – 1894) was a
German physician and physicist who made
significant contributions to several widely
varied areas of modern science. In
physiology and psychology, he is known for
his mathematics of the eye, theories of
vision, ideas on the visual perception of
space, color vision research, and on the
sensation of tone and perception of sound.
In physics, he is known for his theories on
the conservation of energy, work in
electrodynamics, chemical thermodynamics,
and on a mechanical foundation of
thermodynamics. The largest German
association of research institutions, the
Helmholtz Association, is named after him.
Later developments
In 1876, physicist J. Willard Gibbs, building on the work of
Clausius, Hermann von Helmholtz and others, proposed that the
measurement of "available energy" ΔG in a thermodynamic
system could be mathematically accounted for by subtracting
the "energy loss" TΔS from total energy change of the system
ΔH. These concepts were further developed by James Clerk
Maxwell.
James Clerk Maxwell
James Clerk Maxwell (1831 – 1879) was a
Scottish physicist and mathematician.
Maxwell also helped develop the
Maxwell–Boltzmann distribution, which is
a statistical means of describing aspects
of the kinetic theory of gases. These two
discoveries helped usher in the era of
modern physics, laying the foundation
for such fields as special relativity and
quantum mechanics.
Maxwell is also known for presenting the
first durable colour photograph in 1861
and for his foundational work on the
rigidity of rod-and-joint frameworks like
those in many bridges.
James Clerk Maxwell
His most prominent achievement was formulating classical
electromagnetic theory. This united all previously unrelated
observations, experiments and equations of electricity,
magnetism and even optics into a consistent theory. Maxwell's
equations demonstrated that electricity, magnetism and even
light are all manifestations of the same phenomenon, namely
the electromagnetic field. Subsequently, all other classic laws or
equations of these disciplines became simplified cases of
Maxwell's equations.
Maxwell demonstrated that electric and magnetic fields travel
through space in the form of waves, and at the constant speed
of light. In 1865 Maxwell published A Dynamical Theory of the
Electromagnetic Field. It was with this that he first proposed that
light was in fact undulations in the same medium that is the
cause of electric and magnetic phenomena.
Statistical thermodynamic views
In 1877, Ludwig Boltzmann formulated the alternative definition of
entropy S defined as:
S = kB lnΩ
where
kB is Boltzmann's constant and
Ω is the number of microstates consistent with the given
macrostate.
Boltzmann saw entropy as a measure of statistical "mixedupness"
or disorder. This concept was soon refined by J. Willard Gibbs,
and is now regarded as one of the cornerstones of the theory of
statistical mechanics.
Ludwig Boltzmann
Ludwig Eduard Boltzmann (1844 –
1906) was an Austrian physicist
famous
for
his
founding
contributions in the fields of
statistical
mechanics
and
statistical thermodynamics. He
was one of the most important
advocates for atomic theory at a
time when that scientific model
was still highly controversial.
Ludwig Boltzmann
Boltzmann's most important scientific contributions were in kinetic
theory, including the Maxwell–Boltzmann distribution for molecular
speeds in a gas. In addition, Maxwell–Boltzmann statistics and the
Boltzmann distribution over energies remain the foundations of
classical statistical mechanics. They are applicable to the many
phenomena that do not require quantum statistics and provide a
remarkable insight into the meaning of temperature.
Much of the physics establishment did not share his belief in the reality
of atoms and molecules — a belief shared, however, by Maxwell in
Scotland and Gibbs in the United States. He had a long-running
dispute with the editor of the preeminent German physics journal of
his day, who refused to let Boltzmann refer to atoms and molecules
as anything other than convenient theoretical constructs. Only a
couple of years after Boltzmann's death, Perrin's studies of colloidal
suspensions (1908–1909), based on Einstein's theoretical studies of
1905, confirmed the values of Avogadro's number and Boltzmann's
constant, and convinced the world that the tiny particles really exist.
History of Magnetism
The attempt to account for magnetic attraction as the working of a
soul in the stone led to the first attack of human reason upon
superstition and the foundation of philosophy. After the lapse of
centuries, a new capacity of the lodestone became revealed in
its polarity, or the appearance of opposite effects at opposite
ends; then came the first utilization of the knowledge thus far
gained, in the mariner's compass, leading to the discovery of
the New World, and the throwing wide of all the portals of the
Old to trade and civilization.
In the 11th century, the Chinese scientist Shen Kuo (1031–1095)
was the first person to write of the magnetic needle compass
and that it improved the accuracy of navigation by employing
the astronomical concept of true north, and by the 12th century
the Chinese were known to use the lodestone compass for
navigation. In 1187, Alexander Neckam was the first in Europe
to describe the compass and its use for navigation.
History of Magnetism
Magnetism was one of the few sciences which progressed in
medieval Europe; for in the thirteenth century Peter Peregrinus
conducted experiments on magnetism and wrote the first extant
treatise describing the properties of magnets and pivoting
compass needles. The dry compass was invented around 1300
by Italian inventor Flavio Gioja.
Italian physician Gerolamo Cardano wrote about electricity in De
Subtilitate (1550) distinguishing, perhaps for the first time,
between electrical and magnetic forces. Toward the late 16th
century, a physician, Dr. William Gilbert (1544 - 1603), in De
Magnete, expanded on Cardano's work and invented the New
Latin word electricus from ἤλεκτρον (elektron), the Greek word
for "amber".
History of Electricity
Gilbert also discovered that a heated body lost its electricity and that
moisture prevented the electrification of all bodies, due to the now
well-known fact that moisture impaired the insulation of such bodies.
He also noticed that electrified substances attracted all other
substances indiscriminately, whereas a magnet only attracted iron.
The many discoveries of this nature earned for Gilbert the title of
founder of the electrical science. By investigating the forces on a light
metallic needle, balanced on a point, he extended the list of electric
bodies, and found also that many substances, including metals and
natural magnets, showed no attractive forces when rubbed. Gilbert's
work was followed up by Robert Boyle (1627—1691). Boyle was one
of the founders of the Royal Society when it met privately in Oxford,
and became a member of the Council after the Society was
incorporated by Charles II. in 1663. He worked frequently at the new
science of electricity. He left a detailed account of his researches
under the title of Experiments on the Origin of Electricity. Boyle, in
1675, stated that electric attraction and repulsion can act across a
vacuum.
The Electric Machine
The first electrostatic generators are
called friction machines because of the
friction in the generation process. A
primitive form of frictional electrical
machine was invented around 1663 by
Otto von Guericke (German scientist
1602-1686), using a sulphur globe that
could be rotated and rubbed by hand. It
may not actually have been rotated
during use, but inspired many later
machines that used rotating globes.
Isaac Newton suggested the use of a
glass globe instead of a sulphur one.
Francis Hauksbee (English scientist
1666-1713) improved the basic design.
Electrics and Non-Electrics
In 1729, Stephen Gray conducted a series of experiments that
demonstrated the difference between conductors and non-conductors
(insulators). He classified substances into two categories: "electrics"
like glass, resin and silk and "non-electrics" like metal and water.
"Electrics" conducted charges while "non-electrics" held the charge.
Intrigued by Gray's results, in 1732, C. F. du Fay concluded that all
objects except metals, animals, and liquids could be electrified by
rubbing and that metals, animals and liquids could be electrified by
means of an electric machine, thus discrediting Gray's "electrics" and
"non-electrics" classification of substances.
In 1737 Du Fay and Hawksbee independently discovered what they
believed to be two kinds of frictional electricity; one generated from
rubbing glass, the other from rubbing resin. From this, Du Fay
theorized that electricity consists of two electrical fluids, "vitreous" and
"resinous", that are separated by friction and that neutralize each
other when combined.[34] This two-fluid theory would later give rise to
the concept of positive and negative electrical charges devised by
Benjamin Franklin.
Leyden Jar
The Leyden jar, a type of capacitor for
electrical energy in large quantities,
was invented independently by Ewald
Georg von Kleist in 1744 and by
Pieter van Musschenbroek in 1745—
1746 at Leiden University (the latter
location giving the device its name).
William Watson, when experimenting
with the Leyden jar, discovered in
1747 that a discharge of static
electricity was equivalent to an
electric current. The capacitive
property, now and for many years
availed of in the electric capacitor,
was first observed by Von Kleist of
Leyden in 1754.
Kite Experiment
In 1752, Benjamin Franklin is frequently
confused as the key luminary behind
electricity. William Watson and Benjamin
Franklin share the discovery of electrical
potentials. Benjamin Franklin promoted his
investigations of electricity and theories
through the famous, though extremely
dangerous, experiment of flying a kite
through a storm-threatened sky. A key
attached to the kite string sparked and
charged a Leyden jar, thus establishing the
link between lightning and electricity.
Following these experiments he invented a
lightning rod. It is either Franklin or
Ebenezer Kinnersley of Philadelphia who is
considered as the establisher of the
convention of positive and negative
electricity.
Electricity and Magnetism
To Franz Aepinus, a noted German scholar (1724–1802) is accorded the
credit of having been the first to conceive the view of the reciprocal
relationship of electricity and magnetism. In his work 'Tentamen
Theoria Electricitatis et Magnetism,' published in he formulated a
corresponding theory of magnetism excepting that in the case of
magnetic phenomena the fluids only acted on the particles of iron.
Henry Cavendish of London, England (1731-1810) independently
conceived a theory of electricity nearly akin to that of Aepinus. He also
(1784) was perhaps the first to utilize the electric spark to produce the
explosion of hydrogen and oxygen in the proper proportions to
produce pure water.
About 1784 Charles-Augustin de Coulomb, a French physicist (1736 1806), devised the torsion balance, by means of which he discovered
what is known as Coulomb's law; — The force exerted between two
small electrified bodies varies inversely as the square of the distance;
not as Aepinus in his theory of electricity had assumed, merely
inversely as the distance.
Galvanic Electricity
In 1790 Prof. Luigi Alyisio Galvani on one
occasion, while conducting experiments on
"animal electricity," as he termed it, to which his
attention had been turned by the twitching of a
frog's legs in the presence of an electric
machine, observed that the muscles of a frog
which was suspended on an iron balustrade by
a copper hook that passed through its dorsal
column underwent lively convulsions without
any extraneous cause. Hitherto the only
electricity known was that developed by friction
or rubbing, which was therefore termed frictional
electricity. We now come to the era of galvanic
or voltaic electricity. In 1800, Alessandro Volta
(1745 – 1827, an Italian physicist) discovered
that chemical reactions could be used to create
positively charged anodes and negatively
charged cathodes.
Ampere's Law
In
1819 Hans Christian Ørsted of
Copenhagen (1777 – 1851) discovered
the deflecting effect of an electric current
traversing a wire upon- a suspended
magnetic needle.
This discovery gave a clue to the
subsequently
proved
intimate
relationship between electricity and
magnetism which was promptly followed
up by André-Marie Ampère (1775 – June
1836) who shortly thereafter (1821)
announced his celebrated theory of
electrodynamics, relating to the force
that one current exerts upon another, by
its electro-magnetic effects.
Ohm's Law
Georg Simon Ohm (1789 – 1854, a German
physicist) used a galvanometer to measure
current, and knew that the voltage between
the thermocouple terminals was proportional
to the junction temperature. He then added
test wires of varying length, diameter, and
material to complete the circuit. He found that
his data could be modeled through a simple
equation with variable composed of the
reading from a galvanometer, the length of the
test
conductor,
thermocouple
junction
temperature, and a constant of the entire
setup. From this, Ohm determined his law of
proportionality and published his results. In
1827, he announced the now famous law that
bears his name.
Faraday and Henry
The discovery of electromagnetic induction was
made almost simultaneously, although
independently, by Michael Faraday (1791 –
1867, an English chemist and physicist) and
Joseph Henry (1797 – 1878, an American
scientist who served as the first Secretary of
the Smithsonian Institution, as well as a
founding member of the National Institute for
the Promotion of Science, a precursor of the
Smithsonian Institution). While Faraday's
early results preceded those of Henry, Henry
was first in his use of the transformer
principle. Henry's discovery of self-induction
and his work on spiral conductors using a
copper coil were made public in 1835, just
before those of Faraday.
Maxwell
In
1864 James Clerk Maxwell of Edinburgh announced his
electromagnetic theory of light, which was perhaps the greatest single
step in the world's knowledge of electricity.
Around 1862, Maxwell calculated that the speed of propagation of an
electromagnetic field is approximately that of the speed of light. He
considered this to be more than just a coincidence, and commented
"We can scarcely avoid the conclusion that light consists in the
transverse undulations of the same medium which is the cause of
electric and magnetic phenomena."
Maxwell also showed that the equations predict the existence of waves
of oscillating electric and magnetic fields that travel through empty
space at a speed that could be predicted from simple electrical
experiments. In his 1864 paper A Dynamical Theory of the
Electromagnetic Field, Maxwell wrote, The agreement of the results
seems to show that light and magnetism are affections of the same
substance, and that light is an electromagnetic disturbance
propagated through the field according to electromagnetic laws.