J.J Thomson Essay, Research Paper
Joseph John Thomson was born on December 18, 1856 near Manchester, England. His father died when
“J.J..” was only sixteen. The young Thomson attended Owens College in Manchester, where his professor of
mathematics encouraged him to apply for a scholarship at Trinity College, one of the most prestigious of the
colleges at Cambridge University. Thomson won the scholarship, and in 1880 finished second in his class in
the grueling graduation examination in mathematics. Trinity gave him a fellowship and he stayed on there,
trying to craft mathematical models that would reveal the nature of atoms and electromagnetic forces.
One hundred years ago, amidst glowing glass tubes and the hum of electricity, the British physicist
J.J.. Thomson went venturing into the interior of the atom. At the Cavendish Laboratory at Cambridge
University, Thomson was experimenting with currents of electricity inside empty glass tubes. He was
investigating a long-standing puzzle known as “cathode rays.” His experiments prompted him to make a bold
proposal: these mysterious rays are streams of particles much smaller than atoms, they are in fact minuscule
pieces of atoms. He called these particles “corpuscles,” and suggested that they might make up all of the
matter in atoms. It was startling to imagine a particle residing inside the atom–most people thought that the
atom was indivisible, the most fundamental unit of matter.
Thomson’s speculation was not explicitly supported by his experiments. It took more experimental
work by Thomson and others to sort out the confusion. The atom is now known to contain other particles as
well. Yet Thomson’s bold suggestion that cathode rays were material constituents of atoms turned out to be
correct. The rays are made up of electrons: very small, negatively charged particles that are indeed
fundamental parts of every atom.
Modern ideas and technologies based on the electron, leading to television and the computer and
much else, evolved through many difficult steps. Thomson’s careful experiments and adventurous hypotheses
were followed by crucial experimental and theoretical work by many others in the United Kingdom,
Germany, France and elsewhere. These physicists opened for us a new perspective–a view from inside the
atom.
First, in a variation of an 1895 experiment by Jean Perrin, Thomson built a cathode ray tube ending
in a pair of metal cylinders with a slit in them. These cylinders were in turn connected to an electrometer, a
device for catching and measuring electrical charge. Perrin had found that cathode rays deposited an electric
charge. Thomson wanted to see if, by bending the rays with a magnet, he could separate the charge from the
rays. He found that when the rays entered the slit in the cylinders, the electrometer measured a large amount
of negative charge. The electrometer did not register much electric charge if the rays were bent so they
would not enter the slit. As Thomson saw it, the negative charge and the cathode rays must somehow be
stuck together: you cannot separate the charge from the rays.
All attempts had failed when physicists tried to bend cathode rays with an electric field. Now
Thomson thought of a new approach. A charged particle will normally curve as it moves through an electric
field, but not if it is surrounded by a conductor (a sheath of copper, for example). Thomson suspected that
the traces of gas remaining in the tube were being turned into an electrical conductor by the cathode rays
themselves. To test this idea, he took great pains to extract nearly all of the gas from a tube, and found that
now the cathode rays did bend in an electric field after all.
Thomson concluded from these two experiments, “I can see no escape from the conclusion that
[cathode rays] are charges of negative electricity carried by particles of matter.” But, he continued, “What
are these particles? are they atoms, or molecules, or matter in a still finer state of subdivision?”
Thomson’s third experiment sought to determine the basic properties of the particles. Although he couldn’t
measure directly the mass or the electric charge of such a particle, he could measure how much the rays
were bent by a magnetic field, and how much energy they carried. From this data he could calculate the ratio
of the mass of a particle to its electric charge (m/e). He collected data using a variety of tubes and using
different gases.
Theories about the atom proliferated in the wake of Thomson’s 1897 work. If Thomson had found
the single building block of all atoms, how could atoms be built up out of these corpuscles? Thomson
proposed a model, sometimes called the “plum pudding” or “raisin cake” model, in which thousands of tiny,
negatively charged corpuscles swarm inside a sort of cloud of massless positive charge. This theory was
struck down by Thomson’s own former student, Ernest Rutherford. Using a different kind of particle beam,
Rutherford found evidence that the atom has a small core, a nucleus. Rutherford suggested that the atom
might resemble a tiny solar system, with a massive, positively charged center circled by only a few electrons.
Later this nucleus was found to be built of new kinds of particles (protons and neutrons), much heavier than
electrons.
The results were astounding. Just as Emil Wiechert had reported earlier that year, the
mass-to-charge ratio for cathode rays turned out to be over one thousand times smaller than that of a
charged hydrogen atom. Either the cathode rays carried an enormous charge (as compared with a charged
atom), or else they were amazingly light relative to their charge.
The choice between these possibilities was settled by Philipp Lenard. Experimenting on how
cathode rays penetrate gases, he showed that if cathode rays were particles they had to have a very small
mass–far smaller than the mass of any atom. The proof was far from conclusive. But experiments by others
in the next two years yielded an independent measurement of the value of the charge (e) and confirmed this
remarkable conclusion.
Thomson boldly announced the hypothesis that “we have in the cathode rays matter in a new state,
a state in which the subdivision of matter is carried very much further than in the ordinary gaseous state: a
state in which all matter… is of one and the same kind; this matter being the substance from which all the
chemical elements are built up.” Thomson presented three hypotheses about cathode rays based on his 1897
experiments: Cathode rays are charged particles (which he called “corpuscles”), these corpuscles are
constituents of the atom, and the corpuscles are the only constituents of the atom.
Thomson’s speculations met with some skepticism. The second and third hypotheses were
especially controversial (the third hypothesis indeed turned out to be false). Years later he recalled, “At first
there were very few who believed in the existence of these bodies smaller than atoms. I was even told long
afterwards by a distinguished physicist who had been present at my lecture at the Royal Institution that he
thought I had been ‘pulling their legs.’”
On January 2, 1890, J.J. married Rose Paget. They had 2 kids. His son, George Thomson also
went into the field of atomics. Throughout the marriage, the word “electron,” coined by G. Johnstone
Stoney in 1891, had been used to denote the unit of charge found in experiments that passed electric current
through chemicals. In this sense the term was used by Joseph Larmor, J.J.. Thomson’s Cambridge classmate.
Larmor devised a theory of the electron that described it as a structure in the ether. But Larmor’s theory did
not describe the electron as a part of the atom. When it was discovered in 1897 that Thomson’s corpuscles
were really “free electrons,” he was actually disagreeing with Thomson’s hypotheses. FitzGerald had in mind
the kind of “electron” described by Larmor’s theory.
Gradually scientists accepted Thomson’s first and second hypotheses, although with some subtle
changes in their meaning. Experiments by Thomson, Lenard, and others through the crucial year of 1897
were not enough to settle the uncertainties. In 1906, Thomson won the Nobel Peace Prize for his work and
in 1918 he became the master of his college. J.J. deceased on August 30th, 1940. Real understanding
required many more experiments over later years
Другие работы по теме:
Briar Rose Essay Research Paper In a
Briar Rose Essay, Research Paper In a nutshell: Briar Rose is the story of the Holocaust intertwined with the fairy tale of Sleeping Beauty. The story begins with the death of the “Gemma,” the grandmother of Becca. Through out Becca?s life
The Pigman
– Analysis Of John Conlan Essay, Research Paper John Conlan is a main character in the book The Pigman. He doesn’t act, think and have a social reputation as many people might
The Pigman Essay Research Paper In the
The Pigman Essay, Research Paper In the novel, The Pigman, writing by Paul Zindel the main characters are Mr.Pignati, John and Lorraine. They all meet by chance and each becomes a trespasser on another’s life. However, John and Lorraine each gain something from their experience with the Mr.Pignati. Mr.Pignati, John and Lorraine all have their own individual reasons and desires for wanting to be with each character.
King Henry IV And Joseph Strorm
: Archtypical Fathers Essay, Research Paper King Henry IV and Joseph Strorm: Archtypical Fathers An ideal father is one who is both caring and understanding. To fit this
Jesus In John Essay Research Paper Jesus
Jesus In John Essay, Research Paper Jesus in John When reading the gospels of the New Testament, it becomes evident that the personality of each of the authors affected their understanding, interpretation, and impression of Jesus and his works. In John, the gospel that I chose to read for this paper, Jesus is portrayed in a more godlike, omnipotent manner.
Joseph Essay Research Paper Joseph was seventeen
Joseph Essay, Research Paper Joseph was seventeen , he was loved in Israel . His father loved Joseph and his brothers were jealous . Brothers were thinking of killing Joseph . They threw him into the well . Then they got him out and sold it to Midianie for twenty
Genesis Essay Research Paper Analysis PaperGenesis 39
Genesis Essay, Research Paper Analysis Paper Genesis 39: 1-23 In this passage, there are many spiritual factors in this chapter. God uses many phrases to translate into spiritual factors that were used back then and today also.
Chrysalids Essay Research Paper In the words
Chrysalids Essay, Research Paper In the words of the Houghton Mifflin Canadian dictionary, deviation is defined as “an abnormality, a departure”. David Strorm, the protagonist in the
Blind Ambition Essay Research Paper Blind AmbitionJohn
Blind Ambition Essay, Research Paper Blind Ambition John Dean was counsel to the President. He wanted power and superiority. To advance up the ladder, John Dean got involved in certain activities. Some of which were not legal. One example would be the extortion of money. John Dean didn?t really think of the consequences but of the rewards.
The Chrysalids Essay Research Paper John Wyrndham
The Chrysalids Essay, Research Paper John Wyrndham the author of The Chrysalids is an extraordinary writer who has created this book in the state of two totally different worlds. Wyrndham has based this book on the different views toward blasphamies and how the characters all have a different approach on the subject.
John Gotti Essay Research Paper email PPMafUnBosaolcomtitle
John Gotti Essay, Research Paper email: PPMafUnBos@aoltitle: “The King of New York:” The Life and Times of the “Dapper Don,” John GottiJohn Gotti was born John Joseph Gotti, Jr. on October27, 1940 to Fannie nd John Joseph Gotti Sr. He is ofNeapolitan background, not Sicilian like most people think.His grandparents immigrated from a small village in thevicinity of Naples which was inhabited by Teutonic maraudersin the sixth century, the Goths.
Jfk Jr Essay Research Paper John F
Jfk Jr Essay, Research Paper John F. Kennedy Jr. John Fitzgerald Kennedy Jr. was born on November 25, 1960, two and a half weeks after his father was elected president of the United States and less than two months before his father was inaugurated. Three years later, that father, murdered by an assassin’s bullet, was buried on John’s third birthday.
American Flag Essay Research Paper Betsy Ross
American Flag Essay, Research Paper Betsy Ross lived from 1752 to 1836. She was born to Elizabeth Griscom in Philadelphia. In 1773 she ran away with John Ross to get married. But her
Joseph Priestley Essay Research Paper Joseph Priestley
Joseph Priestley Essay, Research Paper Joseph Priestley was born in England on March 13, 1733, and showed a great talent for science and languages from an early age. Priestley performed many important scientific experiments, among them the discovery that the gas produced by the fermentation of grain (later identified as carbon dioxide) could be dissolved in water to produce the pleasant drink called seltzer.
Stalin His Life Essay Research Paper No
Stalin His Life Essay, Research Paper No man more fully epitomized this era than Joseph Stalin did. As political, economic, and social leader, Joseph Stalin has emotionally, physically, psychologically, politically, economically, and socially affected Russia even to this day.
Joseph Patrick Kennedy Essay Research Paper Joseph
Joseph Patrick Kennedy Essay, Research Paper Joseph Patrick Kennedy was born on September 6, 1888, in Boston Massachusetts. He was born the son of Patrick Joseph Kennedy, a local politician and successful businessman, and his wife Mary Augusta Hickey Kennedy. His parents wanted only the best for young Joe.
John Bardeen Essay Research Paper Bardeen John
John Bardeen Essay, Research Paper Bardeen, John 1908-91, American physicist; b. Madison, Wis. He was known for his studies of semiconductivity and other aspects of SOLID-STATE PHYSICS. The first
Zues Essay Research Paper A Stranger in
Zues Essay, Research Paper A Stranger in the Valley of the Kings by: Ahmed Osman The book “Stranger in the Valley of the Kings” was an account of the pharaohs of Egypt in the Hyksos’ rain over Egypt.
Jewishness Of Jesus Essay Research Paper Joseph
Jewishness Of Jesus Essay, Research Paper Joseph Foster Humanities 120 November 29, 2000 The Jewishness Jesus Jesus was raised a Jew from the time he was born. All of Jesus? ancestors were Jews. His family followed all of the Jewish customs starting off with his circumcision when he was eight days old (Luke 2:21).
Joseph Stalin Essay Research Paper Joseph StalinJoseph
Joseph Stalin Essay, Research Paper Joseph Stalin Joseph Stalin is credited as being one of the most powerful leaders of all time. He helped his country, the Soviet Union, become a dominating world power. Born on December 21, 1879 under his original name Iosif Vissarionovich Dzhugashvili, he renamed himself Stalin meaning “man of steel.” Stalin was the unchallenged leader of the USSR from 1929 until his death in 1953.
Crucible Essay Research Paper Tragic Hero EssayThe
Crucible Essay, Research Paper Tragic Hero Essay The historic happenings of the Salem Witch Trials are told in the story of the Crucible. In the Crucible, the main character is John Proctor. John Proctor is a tragic hero who is a great man but has one single flaw, pride, which will lead to his destruction.
Life Of Jesus Essay Research Paper The
Life Of Jesus Essay, Research Paper The Life of Jesus In this essay on Jesus, I am going to talk a lot about what made Jesus such an important figure. I am going to discuss Jesus birth, death and some of what in between.
Modern Atom Model Essay Research Paper The
Modern Atom Model Essay, Research Paper The evolution of the modern atom model took several years to evolved with contribution from different scientists. One of these scientists, the first to come up with a modern model of the atom is JJ Thomson. Thomson proposes that the structure of an atom is mainly a sphere.
Basics On Keats Essay Research Paper John
Basics On Keats Essay, Research Paper -John Keats was born in 1795 and died in 1821 -John Keats was born in Moorfield, England -John Keats had two brothers, George and Tom, and a sister Fanny
Poem Color Of My Love Essay Research
Paper Color of My Love ~Thomson Vaidyan A red, red rose for you, my love My lone angel, my sweetest sweet Lil’ pretty princess in that hot red With those matching sweet, crimson lips
Evolution Of Modern Atom Essay Research Paper
The evolution of the modern atom model took several years to evolved with contribution from different scientists. One of these scientists, the first to come up with a modern model of the atom is JJ Thomson. Thomson proposes that the structure of an atom is mainly a sphere. A sphere that is filled with positive electronic field and contains tiny particles that has a negative charge.
Joseph And Forgiveness Essay Research Paper Joseph
Joseph And Forgiveness Essay, Research Paper Joseph and Forgiveness The story of Joseph has several important themes, but the one I thought was the most significant was the unbelievable forgiveness of Joseph toward his brothers.
An Excerpt From Joseph Freeman
’s AN AMERICAN TESTAMENT Essay, Research Paper from An American Testament by novelist and apparatchik Joseph Freeman (1936) Reconciliation to the city is only a prelude to our transformation. The conflict of
Atomic Physics Essay Research Paper subject
Atomic Physics Essay, Research Paper subject = physics title = Atomic Physics papers = Please put your paper here. ATOMIC PHYSICS Atomic Physics- is the study of atomic matter.