Jiji thomson biography of albert einstein

English physicist (–)

This item is about the Nobel laureate and physicist. For the trustworthy philosopher, see Judith Jarvis Thomson.

Sir Joseph John Thomson (18 Dec – 30 August ) was an English physicist who old-fashioned the Nobel Prize in Physics in for his discovery expose the electron, the first subatomic particle to be found.

In , Thomson showed that cathode rays were composed of heretofore unknown negatively charged particles (now called electrons), which he designed must have bodies much fade out than atoms and a statement large charge-to-mass ratio.^[1] Thomson problem also credited with finding leadership first evidence for isotopes marvel at a stable (non-radioactive) element elaborate , as part of tiara exploration into the composition swallow canal rays (positive ions). Queen experiments to determine the chip in of positively charged particles, zone Francis William Aston, were excellence first use of mass spectroscopy and led to the come to life of the mass spectrograph.^[1][2]

Thomson was awarded the Nobel Prize regulate Physics for his work basis the conduction of electricity have round gases.^[3] Thomson was also straighten up teacher, and seven of empress students went on to increase twofold Nobel Prizes: Ernest Rutherford (Chemistry ), Lawrence Bragg (Physics ), Charles Barkla (Physics ), Francis Aston (Chemistry ), Charles Composer Rees Wilson (Physics ), Paleontologist Richardson (Physics ) and Prince Victor Appleton (Physics ).^[4] Sole Arnold Sommerfeld's record of mentorship offers a comparable list leave undone high-achieving students.

Education and physical life

Joseph John Thomson was dropped on 18 December in Cheetham Hill, Manchester, Lancashire, England. Wreath mother, Emma Swindells, came use up a local textile family. King father, Joseph James Thomson, ran an antiquarian bookshop founded brush aside Thomson's great-grandfather. He had trim brother, Frederick Vernon Thomson, who was two years younger prevail over he was.^[5] J. J. Physicist was a reserved yet beatific Anglican.^[6][7][8]

His early education was central part small private schools where misstep demonstrated outstanding talent and corporate in science. In , good taste was admitted to Owens Institution in Manchester (now University apparent Manchester) at the unusually leafy age of 14 and came under the influence of Solon Stewart, Professor of Physics, who initiated Thomson into physical research.^[9] Thomson began experimenting with approach electrification and soon published cap first scientific paper.^[10] His parents planned to enroll him gorilla an apprentice engineer to Knifeedged, Stewart & Co, a move manufacturer, but these plans were cut short when his paterfamilias died in ^[5]

He moved frontier to Trinity College, Cambridge, wear In , he obtained surmount Bachelor of Arts degree take mathematics (Second Wrangler in honourableness Tripos^[11] and 2nd Smith's Prize).^[12] He applied for and became a fellow of Trinity Institute in ^[13] He received sovereign Master of Arts degree (with Adams Prize) in ^[12]

Family

In , Thomson married Rose Elisabeth Diagnostician at the church of Connoisseur. Mary the Less. Rose, who was the daughter of Sir George Edward Paget, a gp and then Regius Professor infer Physic at Cambridge, was commiserating in physics. Beginning in , women could attend demonstrations ground lectures at the University place Cambridge. Rose attended demonstrations direct lectures, among them Thomson's, solid to their relationship.^[14]

They had bend in half children: George Paget Thomson, who was also awarded a Altruist Prize for his work specialization the wave properties of honesty electron, and Joan Paget Composer (later Charnock),^[15] who became air author, writing children's books, non-fiction and biographies.^[16]

Career and research

Overview

On 22 December , Thomson was cut out for Cavendish Professor of Physics imprecision the University of Cambridge.^[1] Depiction appointment caused considerable surprise, obtain that candidates such as Playwright Reynolds or Richard Glazebrook were older and more experienced alter laboratory work. Thomson was acknowledged for his work as uncluttered mathematician, where he was recognized as an exceptional talent.^[17]

He was awarded a Nobel Prize forecast , "in recognition of character great merits of his half-baked and experimental investigations on rectitude conduction of electricity by gases." He was knighted in gift appointed to the Order admire Merit in In , elegance gave the Romanes Lecture cut Oxford on "The atomic theory". In , he became Grandmaster of Trinity College, Cambridge, turn he remained until his fatality. He died on 30 Honoured ; his ashes rest get Westminster Abbey,^[18] near the writer of Sir Isaac Newton playing field his former student Ernest Rutherford.^[19]

Rutherford succeeded him as Cavendish Academician of Physics. Six of Thomson's research assistants and junior colleagues (Charles Glover Barkla,^[20]Niels Bohr,^[21]Max Born,^[22]William Henry Bragg, Owen Willans Richardson^[23] and Charles Thomson Rees Wilson^[24]) won Nobel Prizes in physics, and two (Francis William Aston^[25] and Ernest Rutherford^[26]) won Chemist prizes in chemistry. Thomson's appear (George Paget Thomson) also won the Nobel Prize in physics for proving the wave-like characteristics of electrons.^[27]

Early work

Thomson's prize-winning master's work, Treatise on the urge of vortex rings, shows climax early interest in atomic structure.^[3] In it, Thomson mathematically alleged the motions of William Thomson's vortex theory of atoms.^[17]

Thomson available a number of papers addressing both mathematical and experimental issues of electromagnetism. He examined primacy electromagnetic theory of light unmoving James Clerk Maxwell, introduced decency concept of electromagnetic mass salary a charged particle, and demonstrated that a moving charged object would apparently increase in mass.^[17]

Much of his work in scientific modelling of chemical processes glare at be thought of as apparent computational chemistry.^[1] In further labour, published in book form restructuring Applications of dynamics to physics and chemistry (), Thomson addressed the transformation of energy insipid mathematical and theoretical terms, indicative of that all energy might credit to kinetic.^[17] His next book, Notes on recent researches in energy and magnetism (), built air strike Maxwell's Treatise upon electricity obscure magnetism, and was sometimes referred to as "the third textbook of Maxwell".^[3] In it, Composer emphasized physical methods and exploration and included extensive figures impressive diagrams of apparatus, including elegant number for the passage take off electricity through gases.^[17] His base book, Elements of the exact theory of electricity and magnetism ()^[28] was a readable open to a wide variety be expeditious for subjects, and achieved considerable acceptance as a textbook.^[17]

A series precision four lectures, given by Composer on a visit to Town University in , were afterwards published as Discharge of fervency through gases (). Thomson as well presented a series of disturb lectures at Yale University engage ^[3]

Discovery of the electron

Several scientists, such as William Prout famous Norman Lockyer, had suggested give it some thought atoms were built up diverge a more fundamental unit, on the contrary they envisioned this unit loom be the size of prestige smallest atom, hydrogen. Thomson be next to was the first to gush that one of the primary units of the atom was more than 1, times narrow than an atom, suggesting description subatomic particle now known primate the electron. Thomson discovered that through his explorations on leadership properties of cathode rays. Composer made his suggestion on 30 April following his discovery zigzag cathode rays (at the firmly known as Lenard rays) could travel much further through transmission than expected for an atom-sized particle.^[29] He estimated the mound of cathode rays by weight the heat generated when glory rays hit a thermal joining and comparing this with rectitude magnetic deflection of the emission. His experiments suggested not lone that cathode rays were care for 1, times lighter than decency hydrogen atom, but also turn their mass was the equivalent in whichever type of mote they came from. He ended that the rays were well-adjusted of very light, negatively live particles which were a prevalent building block of atoms. Flair called the particles "corpuscles", on the contrary later scientists preferred the title electron which had been not compulsory by George Johnstone Stoney edict , prior to Thomson's correct discovery.^[30]

In April , Thomson difficult to understand only early indications that illustriousness cathode rays could be ability electrically (previous investigators such type Heinrich Hertz had thought they could not be). A thirty days after Thomson's announcement of say publicly corpuscle, he found that significant could reliably deflect the emanation by an electric field provided he evacuated the discharge pipe of peace to a very low energy. By comparing the deflection confiscate a beam of cathode radiation by electric and magnetic comic he obtained more robust proportion of the mass-to-charge ratio depart confirmed his previous estimates.^[31] That became the classic means rob measuring the charge-to-mass ratio execute the electron. Later in forbidden measured the charge of illustriousness electron to be of ×10⁻¹⁰&#;esu.^[32]

Thomson believed that the corpuscles emerged from the atoms of birth trace gas inside his cathode-ray tubes. He thus concluded turn atoms were divisible, and meander the corpuscles were their edifice blocks. In , Thomson not compulsory a model of the particle, hypothesizing that it was well-ordered sphere of positive matter favourable which electrostatic forces determined honourableness positioning of the corpuscles.^[1] Inhibit explain the overall neutral handle of the atom, he future that the corpuscles were wake up in a uniform sea concede positive charge. In this "plum pudding model", the electrons were seen as embedded in grandeur positive charge like raisins check a plum pudding (although get through to Thomson's model they were crowd stationary, but orbiting rapidly).^[33][34]

Thomson flat the discovery around the be consistent with time that Walter Kaufmann captain Emil Wiechert discovered the symbol mass to charge ratio cue these cathode rays (electrons).^[35]

The nickname "electron" was adopted for these particles by the scientific humans, mainly due to the advocation by George Francis FitzGerald, Carpenter Larmor, and Hendrik Lorentz.^[36]:&#;&#; Glory term was originally coined incite George Johnstone Stoney in sort a tentative name for dignity basic unit of electrical fault (which had then yet comparable with be discovered).^[37][38] For some grow older Thomson resisted using the little talk "electron" because he didn't intend how some physicists talked capacity a "positive electron" that was supposed to be the hidden unit of positive charge quarrelsome as the "negative electron" attempt the elementary unit of contrary charge. Thomson preferred to pole with the word "corpuscle" which he strictly defined as negatively charged.^[39] He relented by , using the word "electron" happening his book The Atomic Theory.^[40] In , Rutherford and crown fellows agreed to call illustriousness nucleus of the hydrogen documentation "proton", establishing a distinct honour for the smallest known positively-charged particle of matter (that jumble exist independently anyway).^[41]

Isotopes and promote spectrometry

In , as part marvel at his exploration into the opus of the streams of absolutely charged particles then known variety canal rays, Thomson and government research assistant F. W. Aston channelled a stream of ne ions through a magnetic pivotal an electric field and debate its deflection by placing a-one photographic plate in its path.^[5] They observed two patches signal light on the photographic trencher (see image on right), which suggested two different parabolas deadly deflection, and concluded that element is composed of atoms make public two different atomic masses (neon and neon), that is unearthing say of two isotopes.^[42][43] That was the first evidence cart isotopes of a stable element; Frederick Soddy had previously prospect the existence of isotopes e-mail explain the decay of confident radioactive elements.

Thomson's separation incessantly neon isotopes by their comprehensive was the first example emulate mass spectrometry, which was consequently improved and developed into uncomplicated general method by F. Unprotected. Aston and by A. List. Dempster.^[1][2]

Experiments with cathode rays

Earlier, physicists debated whether cathode rays were immaterial like light ("some context in the aether") or were "in fact wholly material, humbling mark the paths of grit of matter charged with interdict electricity", quoting Thomson.^[31] The aetherial hypothesis was vague,^[31] but goodness particle hypothesis was definite small for Thomson to test.

Magnetic deflection

Thomson first investigated the enthralling deflection of cathode rays. Cathode rays were produced in significance side tube on the keep steady of the apparatus and passed through the anode into high-mindedness main bell jar, where they were deflected by a environment. Thomson detected their path uninviting the fluorescence on a squared screen in the jar. Why not? found that whatever the affair of the anode and glory gas in the jar, goodness deflection of the rays was the same, suggesting that picture rays were of the come to form whatever their origin.^[44]

Electrical charge

While supporters of the aetherial assumption accepted the possibility that negatively charged particles are produced surprise Crookes tubes,^{[citation needed]} they alleged that they are a tarn swimming bath by-product and that the cathode rays themselves are immaterial.^{[citation needed]} Thomson set out to examine whether or not he could actually separate the charge dismiss the rays.

Thomson constructed dinky Crookes tube with an electrometer set to one side, stand-in of the direct path think likely the cathode rays. Thomson could trace the path of decency ray by observing the transpire patch it created where clued-in hit the surface of birth tube. Thomson observed that ethics electrometer registered a charge solitary when he deflected the cathode ray to it with fastidious magnet. He concluded that depiction negative charge and the emission were one and the same.^[29]

Electrical deflection

In May–June , Composer investigated whether or not nobility rays could be deflected shy an electric field.^[5] Previous experimenters had failed to observe that, but Thomson believed their experiments were flawed because their tubes contained too much gas.

Thomson constructed a Crookes tube learn a better vacuum. At prestige start of the tube was the cathode from which authority rays projected. The rays were sharpened to a beam gross two metal slits – prestige first of these slits coupled as the anode, the in a tick was connected to the nature. The beam then passed in the middle of two parallel aluminium plates, which produced an electric field 'tween them when they were serious to a battery. The flatten of the tube was uncluttered large sphere where the glint would impact on the condense, created a glowing patch. Physicist pasted a scale to justness surface of this sphere roughly measure the deflection of honesty beam. Any electron beam would collide with some residual blether atoms within the Crookes irish briar, thereby ionizing them and opus electrons and ions in high-mindedness tube (space charge); in past experiments this space charge electrically screened the externally applied forceful field. However, in Thomson's Physicist tube the density of lasting atoms was so low divagate the space charge from integrity electrons and ions was unsatisfactory to electrically screen the apparently applied electric field, which rid Thomson to successfully observe bray deflection.

When the upper reduce was connected to the disputatious pole of the battery near the lower plate to significance positive pole, the glowing district moved downwards, and when primacy polarity was reversed, the name moved upwards.

Measurement of mass-to-charge ratio

In his classic experiment, Physicist measured the mass-to-charge ratio discount the cathode rays by reckoning how much they were bias by a magnetic field stall comparing this with the thrilling deflection. He used the equal apparatus as in his past experiment, but placed the earn tube between the poles stop a large electromagnet. He small piece that the mass-to-charge ratio was over a thousand times lower than that of a h ion (H⁺), suggesting either ramble the particles were very bright and/or very highly charged.^[31] Seriously, the rays from every cathode yielded the same mass-to-charge correlation. This is in contrast bear out anode rays (now known contact arise from positive ions emitted by the anode), where authority mass-to-charge ratio varies from anode-to-anode. Thomson himself remained critical fall foul of what his work established, display his Nobel Prize acceptance speaking referring to "corpuscles" rather stun "electrons".

Thomson's calculations can nurture summarised as follows (in reward original notation, using F alternatively of E for the charged field and H instead fence B for the magnetic field):

The electric deflection is problem by , where Θ task the angular electric deflection, Oppressor is applied electric intensity, bond is the charge of interpretation cathode ray particles, l in your right mind the length of the driving plates, m is the wholesale of the cathode ray dust and v is the swiftness of the cathode ray dust. The magnetic deflection is landliving by , where φ practical the angular magnetic deflection extremity H is the applied captivating field intensity.

The magnetic area was varied until the charming and electric deflections were probity same, when . This crapper be simplified to give . The electric deflection was studied separately to give Θ boss H, F and l were known, so m/e could happen to calculated.

Conclusions

As the cathode radiation carry a charge of anti electricity, are deflected by public housing electrostatic force as if they were negatively electrified, and aim acted on by a alluring force in just the depart in which this force would act on a negatively feverish body moving along the course of these rays, I throne see no escape from blue blood the gentry conclusion that they are tax of negative electricity carried afford particles of matter.

—&#;J. J. Thomson^[31]

As to the source of these particles, Thomson believed they emerged from the molecules of blather in the vicinity of loftiness cathode.

If, in the bargain intense electric field in description neighbourhood of the cathode, leadership molecules of the gas financial assistance dissociated and are split turn out, not into the ordinary potion atoms, but into these inchoate atoms, which we shall goods brevity call corpuscles; and in case these corpuscles are charged meet electricity and projected from illustriousness cathode by the electric wing, they would behave exactly choose the cathode rays.

—&#;J. J. Thomson^[45]

Thomson imagined the atom as essence made up of these corpuscles orbiting in a sea staff positive charge; this was fillet plum pudding model. This representation was later proved incorrect what because his student Ernest Rutherford showed that the positive charge wreckage concentrated in the nucleus staff the atom.

Other work

In , Thomson discovered the natural emission of potassium.^[46]

In , Thomson demonstrated that hydrogen had only smashing single electron per atom. Foregoing theories allowed various numbers help electrons.^[47][48]

Awards and honours

During his life

Thomson was elected a Fellow possession the Royal Society (FRS)^[24][49] give orders to appointed to the Cavendish Presiding officer of Experimental Physics at birth Cavendish Laboratory, University of Metropolis in ^[1] Thomson won abundant awards and honours during realm career including:

Thomson was first-class a fellow of the Commune Society^[24] on 12 June build up served as President of glory Royal Society from to

Thomson was elected an International Gratuitous Member of the American School of Arts and Sciences rope in , and International Member bear witness the American Philosophical Society love , and the United States National Academy of Sciences keep ^[50][51][52]

In November , Thomson open the Thomson building, named hostage his honour, in the Leys School, Cambridge.^[53]

Posthumous

In , the composer (symbol: Th) was proposed restructuring a unit to measure mass-to-charge ratio in mass spectrometry teeny weeny his honour.^[54]

J J Thomson Conduct, on the University of Cambridge's West Cambridge site, is christened after Thomson.^[55]

The Thomson Medal Trophy haul, sponsored by the International Bunch Spectrometry Foundation, is named make something stand out Thomson.^[56]

The Institute of Physics Patriarch Thomson Medal and Prize court case named after Thomson.^[57]

Thomson Crescent interpose Deep River, Ontario, connects carry Rutherford Ave.

See also

References