Nickolaus Copernicus (February 19, 1473 – May 24, 1543)

Copernicus Jordano Bruno or Giordano Bruno

Thank you Blair. The statue of Bruno at the very same place he was burnt at stake (Campo de' Fiori in Rome).. He is he 1st martyr for science. click the image. to know more.

Heliocentric system introduced by Copernicus. Uranus, Neptune and Pluto were not known yet. source, to learn more.

Polish Monk. The EArth is not at the center of the solar system but the Sun is. Against the belief introduced by Aristotle and worked later by Ptolemy. It was thought the EArth is at the center and the Sun and the planets orbit along perfect circles. (the Greek really loved circles, the perfect shape).  Copernicus placed the Sun at the center and the planets around. He thought, as every one at the time, planets move on Cristal spheres. They could not other wise explain why the planets stay on their orbit instead of flying away. 

Of course Newton showed that they stay in orbit because of the gravitational force and the principle of inertia. (Remember ? they want to keep going in a straight line at the same speed, but not they can't because the force of gravity is pulling them toward the Sun ). 

Copernicus asked his book to be published only after his death not to upset the Church (he didn't to be tortured and killed). He also hided his idea behind a lot of writing about the old ideas. Few scholars paid attention to this breakthrough. But an Italian Monk Jordano Bruno. He believed in Copernicus theory and he even believed there was life in other worlds in the Universe. He was sentenced to be burnt at stake in Rome. You can still see his statue standing on a pillar in Rome. (Which plaza ? )

Galileo Galilei (15 February 1564 – 8 January 1642)

This is the "Galileo lamp" in the Duomo in Pisa. Galileo was 17 years old when he discovered the laws upon which a pendulum is built. The legend said he was using this swinging lamp in the church, using his pulse to find the period. This is not true as the lamp was hanged after the death of Galileo.

Galileo worked a lot with inclined plane. His experiments showed the principle of inertia, the laws of falling body.

Galileo in front of the inquisition. He supported the heliocentric system of Copernicus but had to retract himself to save his life. He was considered as an heretic by the Catholic church of the time.	Here some irony. In Italy, remains of the saints are exhibited in churches. But this is not the finger of a SAint, it is the middle finger of Galileo, maybe a message to those who condemned him to home arrest for the rest  of his life. This finger can be seen in Florence. History of Science Museum	The tower of Pisa and behind the Duomo. It is said that Galileo drops different objects from the top and find out that any body, regardless of its mass, falls at the same rate. This legend is probably not true either.

GAlileo is probably the father of modern Physics. He based his laws or finding on experiments and observations. He is known to have supported the heliocentric system introduced by Copernicus. He based his belief on the observation of the phases on Venus. He used for his observations a telescope (the refractive telescope with lenses) that he had himself invented. Actually, he didn't invent the telescope but he improved it a lot. Then he let people believe he was the inventor.

 ANyway, his invention pleased so much the princes of Venice  that he was given a "tenure track" and a raise at the university of Padua (in the Venetian Republic) and didn't have to worry about money any more. He was able to concentrates on his experiments. He also discovered the four largest moons of Jupiter called the Galilean moons.

Note: Galileo built a refractive telescope that use 2 lenses. The problem is that light can be spread when going through the lenses. This is called the spreading of light or diffraction. As a result, the image is blurred. Newton invented the reflective telescope using mirrors still used today. You don't have this problem.

He built the laws of Kinematics based on his experiments with inclined planes. REmember the odd number law ? proving that the displacement varies as the time squared ? (straight line motion, no friction). He also  found the law of free-falling bodies. All free-falling bodies have the same acceleration. His laws were based on observations, Newton will explain why these laws work by "inventing" the gravitational force , F = ma and by the same token Calculus.

Galileo also investigated the pendulum and discovered that the period on a pendulum only depends on its length.

Galileo supported the heliocentric system of Copernicus. Unlike Copernicus, he wanted every one to know about it and wrote a book in Italian. This was not conformist at all. At this time, scholars would write their book in Latin so only educated people could understand. Galileo, already popular because of his telescope, wrote in Italian on purpose and his book quickly spread out. He got in trouble with the inquisition and had to stay in his home for the rest of his life. 

Galileo and Kepler knew each other. They never met but they exchange some letters. Exactly 1 year after the death of Galileo, Newton.

more about him

extra credits: (how Galileo figured out inertia)


new black hole

Kepler (December 27, 1571 – November 15, 1630)

Kepler. Galileo, Shakespeare, Queen Elizabeth were all contemporaries of Kepler.	Kepler was protestant and had to leave his Catholics country (Germany) to Prague in 1600. It was the 30 years war in Europe. Protestants and Catholics  were fighting. It was a very bloody period.	In Prague Kepler was hired by Tycho Brahe as a mathematician. He was in charge of processing all the precise data collected by Tycho. Tycho had a copper nose. The 2 men could not stand each others. But they needed each other.
click The picture on the left shows tycho collecting data from the planets. He collected these data in a room without ceiling, in his castle. He lived on an island given by the king of Denmark. He was the first astronomer able to collect very high quality data. Only using his naked eyes. Kepler wanted these data badly. Brahe had to go to Prague after a new king disliked him in Denmark.	click image Kepler discovered 3 laws regarding the motion of planets. The second law is a consequence of the conservation of angular momentum we are studying now. In equal time, planets sweep the same area.	click image. Kepler got the data of Tycho after his death. He figured out his 3 laws after years of work. He wrote a book called harmony of the world. It is a mystic about music and the motions on planets. Newtons found the 3 laws and used them for his work. Since the force of gravity was not know, Kepler thought the planets had to moved on geometric shape embedded in each other. He was very good in geometry and the ratio between the  the shapes were matching the ration between the planets distance from the Sun. This paper was an addition to his first publication. Know more.

Kepler greatest achievement was to describe the planet motion.
1) Planets move along ellipses. an ellipse is a conic section like the circle, the parabola and the hyperbola
2) Planets sweep equal area in equal time.
3)Take any 2 planets.  The ratio of their revolutionary period squared = ratio of their distance from the Sun cubed.
That was a huge breakthrough. Newton studied these laws and was able explain them by using calculus and by introducing a  force (force of gravity) that holds the universe together. In addition, Newton showed that any body int he universe, under the influence of gravity, follows a conic section. Depending on the balance between the object Kinetic energy and potential energy. (see me for question).

Even though Kepler wrote a book called harmony of the world , his life was not very happy. He was left by his father who was a mercenary. His mother was trialled for witchcraft and he has to fight to save her life. Very young he was placed in a protestant institution where the activity was praying. He was still very attracted by astronomy (at age 5 his mom took him the top of a hill to watch a comet). His problems were not over. He lost his first wife. His second wife was terrible. He lost 7 of his 11 children. He had to flee Germany for Prague because protestants were persecuted.

In Prague he met Tycho Brahe, an extremely gifted astronomer who had collected extremely good data from the position of Mars and other planets. He hired Kepler as a mathematician. They could not stand each other (they stayed together 18 months). Tycho loved to party and was very arrogant. He played with Kepler, giving him some data only little by little. Finally, Tycho died. Funny episode. Tycho used to drink a lot. At a party, he could not leave the room to go to the bathroom. He had to wait for the king to leave first. His balder exploded and he died. Kepler managed to steal the tycho data to work on it. The result, his famous 3 laws. He also wrote a famous almanac for the king. (the way astronomer were making money, was to work horoscopes for the rich people) . learn more

watch: http://www.learner.org/resources/series42.html?pop=yes&pid=551
move the movie to 14:00
quiz:
1) The conic sections are the ________________, ________________ and the _______________________
2) A)How can you get such curves geometrically ?

B) How to get a circle ? (draw)

C) How to get an ellipse ? (draw)

D) hyperbola ? (draw)

3) What is the eccentricity ?   draw to explain.

Newton ( Christmas Day 1642 - 31 March 1727 )

There is a statue of Sir Isaac Newton in the chapel of Trinity College, Cambridge. When translated from the Latin, the inscription at its base reads Newton Who surpassed all men in genius. more: timelinesciences.	source : NASA website. click image A replica of Newton's 6 inch reflecting telescope of 1672 for the Royal Society.	CLICK IMAGE : Halley's comet/ Halley was a good friend of Newton. He convinced Newton to publish his work about the universal gravitational law. Newton found why the planets stay in orbit around the EArth (Inertia principle + force of gravity) but never published his work. The comet is named after Edmond Halley. He observed the comet in 1682 and realized it was the same object observed by Kepler in Prague and in 1531 by Apianus. The period is 76 years.
Robert Hooke disagree with Newton about the nature of light. Newton saw light as particles called corpuscles. Newton could not stand criticism and hated Hooke. It seems Hook was short and hunchback  and Newton wrote these famous words to Hooke: If I have seen further it is by standing on the shoulders of giants	Newton developed his infinitesimal calculus between 1664 and 1666 when he was temporarily con-fined to his estate in Woolsthorpe, quarantined from an outbreak of Bubonic plague in England. However, Newton did not publish his mathematics. Years later Leibniz published his own infinitesimal methods in a recently established scholarly journal circulated around Europe, the Acta Eruditorum. Leibniz's methods appeared in the Acta in two different articles, one in 1682 and the other in 1684. Thus, while Newton's techniques were developed first, Leibniz was the first to publish. more: http://www1.umn.edu/ships/9-1/calculus.htm	discovered the nature of light and color produced the universal theory of gravity changed ideas about space developed the laws of motion developed whole areas of mathematics including calculus disagreed violently with the deeply held religious beliefs of the day - in particular he did not believe in the Holy Trinity was an enthusiastic alchemist who - amongst many other feats - tasted almost all of the known heavy metals (which we now know are poisonous!) reformed the Royal Mint

The poet Alexander Pope, who lived at the same time as Newton, wrote

Nature and Nature's laws lay hid in night;
God said, 'Let Newton be!' and all was light.

But a English humorist added: It did not last; the devil howling "Ho!
Let Einstein be!" restored the status quo.

The 3 laws of Newton based on calculus could explain and predict any nature's  phenomena given the initial conditions. 

Newton didn't have a happy childhood. His father , an illiterate farmer, has died 3 months before his birth. His mother remarried when he was 3 and left Newton with his grandmother. His stepfather died when he was 10. His mother returned home with 3 other kids and a library of books. Newton didn't go to school until he was 12 years old. He finally went to school but didn't learn any MAth or Science. His classmates didn't like him as he was always the best. He came back home at 17 years old. His mother wanted him to be a farmer but he was really bad at it. His uncle convinced his mother to send him to Trinity College Cambridge (his uncle's old college). There he taught himself Math and Astronomy. He became a Mathematics professor.

Soon after Newton had obtained his degree in August of 1665, the University closed down as a precaution against the Great Plague. For the next 2 years, Newton worked at his home in Woolsthorpe on calculus, optics and the law of gravitation.
While Newton remained at home he laid the foundations for differential and integral calculus, several years before its independent discovery by Leibniz.

In 1672 Newton was elected a fellow of the Royal Society after donating a reflecting telescope. Also in 1672 Newton published his first scientific paper on light and color in the Philosophical Transactions of the Royal Society. The paper was generally well received but Hooke and Huygens objected to Newton's attempt to prove, by experiment alone, that light consists of the motion of small particles rather than waves. The reception that his publication received did nothing to improve Newton's attitude to making his results known to the world. He was always pulled in two directions, there was something in his nature which wanted fame and recognition yet another side of him feared criticism and the easiest way to avoid being criticized was to publish nothing. Certainly one could say that his reaction to criticism was irrational, and certainly his aim to humiliate Hooke in public because of his opinions was abnormal. However, perhaps because of Newton's already high reputation, his corpuscular theory reigned until the wave theory was revived in the 19^th century.

He didn't publish his work until his friend Halley pushed him to. He could not believe Newton kept all his discoveries for himself.
Halley persuaded Newton to write a full treatment of his new physics and its application to astronomy. Over a year later (1687) Newton published the Philosophiae naturalis principia mathematica or Principia as it is always known.

The Philosophiæ Naturalis Principia Mathematica (Latin: "mathematical principles of natural philosophy", often Principia or Principia Mathematica for short) is a three-volume work by Isaac Newton published on July 5, 1687. It contains the statement of Newton's laws of motion forming the foundation of classical mechanics, as well as his law of universal gravitation and a derivation of Kepler's laws for the motion of the planets (which were first obtained empirically). The Principia is widely regarded as one of the most important scientific works ever written.

In formulating his physical theories, Newton had developed a field of mathematics known as calculus. However, the language of calculus was largely left out of the Principia. Instead, Newton recast the majority of his proofs as geometric arguments.

There was a fight between Newton and Leibniz, both of them having invented Calculus. The notations we use now are Leibniz's one.

Over his life, Newton suffered of depression. He could not stand criticism. He hate Hooke and tried to destroy his documents from the Royal Academy after Hooke's death. 

At the end of his life, Newton moved to London to take up the post of warden of the Royal Mint in 1696, a position that he had obtained through the patronage of Charles Montagu, 1st Earl of Halifax, then Chancellor of the Exchequer. He took charge of England's great recoining, somewhat treading on the toes of Master Lucas (and securing the job of deputy comptroller of the temporary Chester branch for Edmond Halley). Newton became perhaps the best-known Master of the Mint upon Lucas' death in 1699, a position Newton held until his death. These appointments were intended as sinecures, but Newton took them seriously, retiring from his Cambridge duties in 1701, and exercising his power to reform the currency and punish clippers and counterfeiters.

In 1703 he was elected president of the Royal Society and was re-elected each year until his death. He was knighted in 1705 by Queen Anne, the first scientist to be so honored for his work. However the last portion of his life was not an easy one, dominated in many ways with the controversy with Leibniz over which had invented the calculus.

He lived for 85 years and died in agony from stones in his bladder. He refused the last sacrament on his deathbed, but is buried in state in Westminster Abbey. watch that movie on Newton's law

MORE on Newton  

MORE (interesting)

Michael Faraday 1791 - 1876

Michael FAraday is one of the greatest experimental physicist. He built the first generator (produces electricity) and the first motor. He built the first transformer, he discovered benzene .... He was the one who introduced the concept of field. (magnetic field, the electric field). He called the fields line of forces. For example, a magnet produces a magnetic field. The field comes out of the North pole and enter its south pole. These lines of force change the space around the magnet and can act a force at a distance. A piece of iron, in the viscinity of the magnet, feels an attractive force. An electric charge also produce an electric field or lines of force. A charge ballon (rubbed against  your hair) is negatively charged and will attract, at a distance, a positive charge.

Faraday was the son of a black smith and didn't get a good education. He had to work at a very young age and his work was to bind books in a bookstore. SO he didn't go to HS and he didn't got o college. He was fond of sciences and taught himself sciences. In 1801 he got to attend the lectures given by Sir Humphry DAvy at the Royal institution.

The lectures of DAvy were really spectacular. He used the newly discovered battery to vaporize some elements or to create impressive arc lights. (like the arc inside an incandescent lamp).
Faraday wrote down all the lectures of DAvy and bind them beautifully in a book. He gave the book as a business card to Davy. Faraday wanted to be part of Davy team. Davy was impressed by the work of Faraday but didn't have a job for him. Until , temporarily blinded by an explosion in his lab, DAvy needed help. Faraday was hired. Faraday soon became an outstanding physicist.

He introduced the concept of field (line of force). At the time, scientists could not explain why an electric current going through a wire could act, at distance, on a compass. (see figure). The compass
needle would move until parallel to the wire. Faraday imagined lines of force spinning around the wire. (magnetic fildd). He also imagined that you could send the lines of force into vibration. (a charged object (balloon rubbed for example) creates an electric field. If you move this object back and forth, a disturbance will propagate along the lines of force. This disturbance is an EM wave. probably a radio wave, that could be detected by an antenna connected to a radio as a fuzz)

Faraday was not a good mathematician but he had seen what nobody could see at the time. Also, he understood that if an electric current can produce a magnetic field then a magnetic field (as long as it oscillates) can produce an (oscillating ) electric current. That was the beginning of the unification of magnetism and electricity. This unification will be completed when James Maxwell wrote his 4 equations describing magnetism and electricity as 2 aspects of the same phenomenon. Faraday met with Maxwell. Maxwell used Faraday's ideas of lines of force. (Playing with the equation Maxwell completed the work of Faraday by finding that light and EM waves are made of an electric field and a magnetic field that reinforce each other and that move in space. A oscillating current creates an oscilatting electric field, that creates an oscillating magnetic field, that creates in turn an oscillating electric field... The wave move really fast. At the speed of light. Out of the equations of Maxwell, pop the speed of light. ).

It seems that DAvy was envious and jalous of his former assitant. He opposed the election of Faraday to the royal institution for years. At one point he objected to honoring Faraday for achieving the first liquefication of chlorine, claiming that he himself deserved credit for the feat. Another time, Davy said his opposition was due to his belief that William Wollaston (1766-1828) had preceded Faraday in discovering electromagnetic rotation. Faraday did finally become a Fellow of the Royal Society in 1824.

Faraday was influenced by his religious believes. He believed in the unification of all the laws of nature. Newton achieved the unification of motion in space and motion on EArth. Maxwell and Faraday achieved the unification between magnetism and electricity.

Today sicnetists still try to unify quantum mechanics (explain the small scale Physics, behavior of particles) and general relatvity (theory of gravity, explain the microcopic world, how galaxies are held together by gravity). Einstein tried. The String's theory tries too. Without success so far.
won't it be nice to explain the law of nature in a few equations?

click image	1820 Hans Christian Ørsted was demonstrating the heating effects of the Voltaic Pile when he noticed that the needle of a compass sitting next to it spun off of north. This occurred every time the Voltaic Pile was in use. The phenomenon was hard to understand. Faraday came with this idea of line of forces created by the current. He found the geometry of these lines of force (magnetic field:)
Faraday used the fact that an electric current behaves like a magnet and can be acted upon, at a distance, by a magnet (or another electric current.) see picture: The current can circulate in the wire because the liquid is mercury and conducts electricity. The circular magnet pushes the wire around and the wire spins around. This was the first motor.
Since a electric current can produce a magnetic field . Faraday asked: Can a magnet create a magnetic field ? Yes as long as the magnet moves inside a coil. This is the way we produce electricity. A chaginf magnetic field will induce a changing electric current. This is called Faradays law of induction	click image
FAradya's life changed when he met Humprhey DAvy. He was supposed to be just an assistant for DAvy but he became more famous than his boss. He also became a famous and talented lecturer at the royal institution of London.	DAvy was a chemist. He discovered several chemical elements including Potassium, chlorine, iodine and Sodium using electrolysis :An electric current might decompose compounds into their constituent elements. In the first Bakerian lecture to the Royal Society in 1806 he described how electro analysis (electrolysis) decomposed pure water into the elemental gases Hydrogen and Oxygen. Davy embarked on a great series of experiments. He used the newly discovered battery (Volta) to create light arc and to vapoize elements in public. People were watching sparks for the first time. Davy's chemical lectures and demonstrations were brilliantly presented and became a fashionable social event. He was the first one to create an arc light. He used to inhale some laughing gaz before his lecture. He died from this habit. (nitrous oxide, which became known as laughing gas. He "breathed 16 quarts of the gas in seven minutes" and became "completely intoxicated" with it. It would be forty-five years later before nitrous oxide would be used as a anesthetic by dentists.)

James Maxwell (1831-1879)  
you don't need to learn about him.

Maxwell was home schooled. He was a genius. Wrote his first paper (Math) when he was 14 years old. Went to TRinity College, Cambridge. Found thet the rings of Saturn was composed of small pieces. Created the first color photo using the 3 colors model.  He developed a Kinetic theory of gases in which particles move around an collide with each other.

Maxwell made several contributions to the scientific community, but his most important achievement was his development of the equations of electromagnetic waves that were first envisioned by Michael Faraday. His theory was presented in 1873 and was entitled "Electricity and Magnetism." . His four equations unify electricity and magnetisme.  This description of electromagnetism is at once simple and complex and is one of the greatest mathematical achievements of the 19th century. Even though these four equations were not directly intended for the theory of relativity, they have made a significant contribution in the development of the theories of relativity by later mathematicians and physicists. For example, Hendrik Lorentz used a slightly modified version of Maxwell's equations in order to develop the concept of length contraction when an object is traveling near the speed of light. Though Maxwell did not envision relativity at the time of the development of his equations describing electromagnetism, they definitely made a significant impact during the early formation of the concepts of relativity.

The 4 equations of Maxwell.  3. Gauss's law. describe the electric field created by a charge. This equation describes electrostatic penomena. How an electric charge generates an electric field. The flux of the electric field through a close surface is proportional to the charge inside the surface. 4. describe the magnetic field produced by a magnet. A single pole can't be isolated. the magnetic filed comes out the North pole and enter the South pole. Or the magnetic flux going through a close surface is zero. 1. Faraday's law. A changing magnetic field (oscillating) produces a changing electric field. That is, you can produce electricity by moving a magnet in and out a close circuit (loop or coil) The flux of the magnetic field through the coil will change over time and produce a circulation of charges in the coil. 2. Ampere's law completed by Maxwell. A loop of direct current produces a constant magnetic field (Ampere's law) . But a changing current (oscillating electric field) will produce a oscillating magnetic field that will, inturn  produce an oscillating electric field... This equation predict the propagation of an EM wave (like visible light, radio wave, x-ray ..). A radio wave was then detected  by Henry Hertz and that proved the equations to be right. Playing with the equations, Maxwell found the speed of light C. Amazing: The equation 4 explaining the magnetism uses the constant: Km = E -7 The equation 3 explaing static electricity uses the constnat: Ke=9E9 if you compute the ratio Ke/Km amazingly you get 9 E16 (m/s)2 which is the square of the speed of light.