prepare a biography of john dalton

Biography of John Dalton, the 'Father of Chemistry'

Wikimedia Commons/Public Domain

• Famous Chemists
• Chemical Laws
• Periodic Table
• Projects & Experiments
• Scientific Method
• Biochemistry
• Physical Chemistry
• Medical Chemistry
• Chemistry In Everyday Life
• Activities for Kids
• Abbreviations & Acronyms
• Weather & Climate
• Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
• B.A., Physics and Mathematics, Hastings College

John Dalton (September 6, 1766–July 27, 1844) was a renowned English chemist , physicist, and meteorologist. His most famous contributions were his atomic theory and color blindness research.

Fast Facts: John Dalton

• Known For : Atomic theory and color blindness research
• Born : September 6, 1766 in Eaglesfield, Cumberland, England
• Parents : Joseph Dalton, Deborah Greenups.
• Died : July 27, 1844 in Manchester, England
• Education : Grammar school
• Published Works :  New System of Chemical Philosophy, Memoirs of the Literary and Philosophical Society of Manchester
• Awards and Honors : The Royal Medal (1826), the fellowship of the Royal Society of London and the Royal Society of Edinburgh, honorary degree from the University of Oxford, associate of the French Academy of Sciences,
• Notable Quote : "Matter, though divisible in an extreme degree, is nevertheless not infinitely divisible. That is, there must be some point beyond which we cannot go in the division of matter....I have chosen the word “atom” to signify these ultimate particles."

Dalton was born into a Quaker family on September 6, 1766. He learned from his father, a weaver, and from Quaker John Fletcher, who taught at a private school. John Dalton started working when he was 10 years old and began teaching at a local school at age 12. Within just a few years, despite their lack of higher education, John and his brother started up their own Quaker school. He could not attend an English university because he was a Dissenter (opposed to being required to join the Church of England), so he learned about science informally from John Gough, a mathematician and experimental physicist. Dalton became a teacher of mathematics and natural philosophy (the study of nature and physics) at age 27 at a dissenting academy in Manchester. He resigned at age 34 and became a private tutor.

Scientific Discoveries and Contributions

John Dalton actually published in a variety of fields, including mathematics and English grammar, but he is best known for his science.

• Dalton kept meticulous daily weather records. He rediscovered the Hadley cell theory of atmospheric circulation. He believed air consisted of about 80% nitrogen and 20% oxygen, unlike most of his peers, who thought air was its own compound.
• Dalton and his brother were both colorblind, but this condition had not been officially discussed or studied. He thought the color perception might be due to a discoloration inside the liquid of the eye and believed there was a hereditary component to red-green color blindness. Although his theory about discolored liquid did not pan out, color blindness became known as Daltonism.
• John Dalton wrote a series of papers describing gas laws. His law on partial pressure became known as Dalton's Law.
• Dalton published the first table of relative atomic weights of atoms of the elements. The table contained six elements, with weights relative to that of hydrogen .

Atomic Theory

Dalton's atomic theory was by far his most famous work; many of his ideas have proven to be either completely correct or largely correct. In fact, Dalton's contributions have earned him the nickname, "the father of chemistry."

According to the Science History Institute, Dalton's atomic theories developed during his explorations of meteorology. He discovered, through experiments, that "the air is not a vast chemical solvent as Antoine-Laurent Lavoisier and his followers had thought, but a mechanical system, where the pressure exerted by each gas in a mixture is independent of the pressure exerted by the other gases, and where the total pressure is the sum of the pressures of each gas." This discovery led him to the idea that "the atoms in a mixture were indeed different in weight and “complexity.”

The idea that there are multiple elements, each made up of its own, unique atoms, was absolutely new and quite controversial at the time. It led to experimentation with the concept of atomic weight, which became the basis for later discoveries in physics and chemistry. Dalton's theories can be summarized as follows:

• Elements are made of tiny particles (atoms).
• Atoms of one element are exactly the same size and  mass as other atoms  of that element.
• Atoms of different elements are different sizes and masses from each other.
• Atoms can't be further subdivided, nor may they be created or destroyed.
• Atoms rearrange during chemical reactions . They may be separated from each other or combined with other atoms.
• Atoms form chemical compounds by combining with each other in simple, whole number ratios.
• Atoms combine according to the "rule of greatest simplicity," which says if atoms only combine in one ratio, it must be a binary one.

From 1837 until his death, Dalton suffered a series of strokes. He continued to work until the day he died, supposedly recording a meteorological measurement on July 26, 1844. The following day, an attendant found him dead beside his bed.

Some points of Dalton's atomic theory have been shown to be false. For example, atoms may be created and split using fusion and fission (although these are nuclear processes and Dalton's theory does hold for chemical reactions). Another deviation from the theory is that isotopes of atoms of a single element may be different from each other (isotopes were unknown in Dalton's time). Overall, the theory was immensely powerful. The concept of atoms of elements endures to the present day.

• “ John Dalton .”  Science History Institute , 31 Jan. 2018.
• Ross, Sydney. “ John Dalton .”  Encyclopædia Britannica , 9 Oct. 2018.
• John Dalton's Atomic Theory
• J.J. Thomson Atomic Theory and Biography
• Niels Bohr and the Manhattan Project
• Atoms and Atomic Theory - Study Guide
• Basic Model of the Atom and Atomic Theory
• Biography of Ernest Rutherford
• Law of Multiple Proportions Example Problem
• Gases Study Guide
• Essential Element Facts in Chemistry
• Chemistry Timeline
• Hydrogen Facts - H or Atomic Number 1
• A Brief History of Atomic Theory
• Topics Typically Covered in Grade 11 Chemistry
• Introduction to the Periodic Table
• Periodic Law Definition in Chemistry
• 10 Famous Meteorologists

By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts.

John Dalton

(1766-1844)

Who Was John Dalton?

During John Dalton's early career, he identified the hereditary nature of red-green color blindness. In 1803 he revealed the concept of Dalton’s Law of Partial Pressures. Also in the 1800s, he was the first scientist to explain the behavior of atoms in terms of the measurement of weight.

Early Life and Career

Dalton was born in Eaglesfield, England, on September 6, 1766, to a Quaker family. He had two surviving siblings. Both he and his brother were born color-blind. Dalton's father earned a modest income as a handloom weaver. As a child, Dalton longed for formal education, but his family was very poor. It was clear that he would need to help out with the family finances from a young age.

After attending a Quaker school in his village in Cumberland, when Dalton was just 12 years old he started teaching there. When he was 14, he spent a year working as a farmhand but decided to return to teaching — this time as an assistant at a Quaker boarding school in Kendal. Within four years, the shy young man was made principal of the school. He remained there until 1793, at which time he became a math and philosophy tutor at the New College in Manchester.

While at New College, Dalton joined the Manchester Literary and Philosophical Society. Membership granted Dalton access to laboratory facilities. For one of his first research projects, Dalton pursued his avid interest in meteorology. He started keeping daily logs of the weather, paying special attention to details such as wind velocity and barometric pressure—a habit Dalton would continue all of his life. His research findings on atmospheric pressure were published in his first book, Meteorological Findings , the year he arrived in Manchester.

During his early career as a scientist, Dalton also researched color blindness—a topic with which he was familiar through firsthand experience. Since the condition had affected both him and his brother since birth, Dalton theorized that it must be hereditary. He proved his theory to be true when genetic analysis of his own eye tissue revealed that he was missing the photoreceptor for perceiving the color green. As a result of his contributions to the understanding of red-green color blindness, the condition is still often referred to as "Daltonism."

Dalton's Law

Dalton's interest in atmospheric pressures eventually led him to a closer examination of gases. While studying the nature and chemical makeup of air in the early 1800s, Dalton learned that it was not a chemical solvent, as other scientists had believed. Instead, it was a mechanical system composed of small individual particles that used pressure applied by each gas independently.

Dalton's experiments on gases led to his discovery that the total pressure of a mixture of gases amounted to the sum of the partial pressures that each individual gas exerted while occupying the same space. In 1803 this scientific principle officially came to be known as Dalton's Law of Partial Pressures. Dalton's Law primarily applies to ideal gases rather than real gases, due to the elasticity and low particle volume of molecules in ideal gases. Chemist Humphry Davy was skeptical about Dalton's Law until Dalton explained that the repelling forces previously believed to create pressure only acted between atoms of the same sort and that the atoms within a mixture varied in weight and complexity.

The principle of Dalton's Law can be demonstrated using a simple experiment involving a glass bottle and large bowl of water. When the bottle is submerged under water, the water it contains is displaced, but the bottle isn't empty; it's filled with the invisible gas hydrogen instead. The amount of pressure exerted by the hydrogen can be identified using a chart that lists the pressure of water vapors at different temperatures, also thanks to Dalton's discoveries. This knowledge has many useful practical applications today. For instance, scuba divers use Dalton's principles to gauge how pressure levels at different depths of the ocean will affect the air and nitrogen in their tanks.

During the early 1800s, Dalton also postulated a law of thermal expansion that illustrated the heating and cooling reaction of gases to expansion and compression. He garnered international fame for his additional study using a crudely fashioned dew point hygrometer to determine how temperature impacts the level of atmospheric water vapor.

Atomic Theory

Dalton's fascination with gases gradually led him to formally assert that every form of matter (whether solid, liquid or gas) was also made up of small individual particles. He referred to the Greek philosopher Democritus of Abdera's more abstract theory of matter, which had centuries ago fallen out of fashion, and borrowed the term "atomos" or "atoms" to label the particles. In an article he wrote for the Manchester Literary and Philosophical Society in 1803, Dalton created the first chart of atomic weights.

Seeking to expand on his theory, he readdressed the subject of atomic weight in his book A New System of Chemical Philosophy , published in 1808. In A New System of Chemical Philosophy , Dalton introduced his belief that atoms of different elements could be universally distinguished based on their varying atomic weights. In so doing, he became the first scientist to explain the behavior of atoms in terms of the measurement of weight. He also uncovered the fact that atoms couldn't be created or destroyed.

Dalton's theory additionally examined the compositions of compounds, explaining that the tiny particles (atoms) in a compound were compound atoms. Twenty years later, chemist Amedeo Avogadro would further detail the difference between atoms and compound atoms.

In A New System of Chemical Philosophy , Dalton also wrote about his experiments proving that atoms consistently combine in simple ratios. What that meant was that the molecules of an element are always made up of the same proportions, with the exception of water molecules.

In 1810 Dalton published an appendix to A New System of Chemical Philosophy . In it he elaborated on some of the practical details of his theory: that the atoms within a given element are all exactly the same size and weight, while the atoms of different elements look—and are—different from one other. Dalton eventually composed a table listing the atomic weights of all known elements.

His atomic theories were quickly adopted by the scientific community at large with few objections. "Dalton made atoms scientifically useful," asserted Rajkumari Williamson Jones, a science historian at the University of Manchester Institute of Science and Technology. Nobel Laureate Professor Sir Harry Kroto, noted for co-discovering spherical carbon fullerenes, identified the revolutionary impact of Dalton's discoveries on the field of chemistry: "The crucial step was to write down elements in terms of their atoms...I don't know how they could do chemistry beforehand, it didn't make any sense."

From 1817 to the day he died, Dalton served as president of the Manchester Literary and Philosophical Society, the organization that first granted him access to a laboratory. A practitioner of Quaker modesty, he resisted public recognition; in 1822 he turned down elected membership to the Royal Society. In 1832 he did, however, begrudgingly accept an honorary Doctorate of Science degree from the prestigious Oxford University. Ironically, his graduation gown was red, a color he could not see. Fortunately for him, his color blindness was a convenient excuse for him to override the Quaker rule forbidding its subscribers to wear red.

In 1833 the government granted him a pension, which was doubled in 1836. Dalton was offered another degree, this time a Doctorate of Laws, by Edinburgh University in 1834. As if those honors were insufficient tribute to the revolutionary chemist, in London, a statue was erected in Dalton's honor--also in 1834. "Dalton was very much an icon for Manchester," said Rajkumari Williams Jones. "He is probably the only scientist who got a statue in his lifetime."

In his later life, Dalton continued to teach and lecture at universities throughout the United Kingdom, although it is said that the scientist was an awkward lecturer with a gruff and jarring voice. Throughout his lifetime, Dalton managed to maintain his nearly impeccable reputation as a devout Quaker. He lived a humble, uncomplicated life focusing on his fascination with science, and never married.

In 1837 Dalton had a stroke. He had trouble with his speech for the next year.

Death and Legacy

After suffering a second stroke, Dalton died quietly on the evening of July 26, 1844, at his home in Manchester, England. He was provided a civic funeral and granted full honors. A reported 40,000 people attended the procession, honoring his contributions to science, manufacturing and the nation's commerce.

By finding a way to "weigh atoms," John Dalton's research not only changed the face of chemistry but also initiated its progression into a modern science. The splitting of the atom in the 20th century could most likely not have been accomplished without Dalton laying the foundation of knowledge about the atomic makeup of simple and complex molecules. Dalton's discoveries also allowed for the cost-efficient manufacturing of chemical compounds, since they essentially give manufacturers a recipe for determining the correct chemical proportions in a given compound.

The majority of conclusions that made up Dalton's atomic theory still stand today.

"Now with nanotechnology, atoms are the centerpiece," said Nottingham University Professor of Chemistry David Garner. "Atoms are manipulated directly to make new medicines, semiconductors and plastics." He went on to further explain, "He gave us the first understanding of the nature of materials. Now we can design molecules with a pretty good idea of their properties."

In 2003, on the bicentennial of Dalton's public announcement of his atomic theory, the Manchester Museum held a tribute to the man, his life and his groundbreaking scientific discoveries.

QUICK FACTS

• Name: John Dalton
• Birth Year: 1766
• Birth date: September 6, 1766
• Birth City: Eaglesfield
• Birth Country: United Kingdom
• Gender: Male
• Best Known For: Chemist John Dalton is credited with pioneering modern atomic theory. He was also the first to study color blindness.
• Journalism and Nonfiction
• Science and Medicine
• Education and Academia
• Astrological Sign: Virgo
• John Fletcher's Quaker grammar school
• Death Year: 1844
• Death date: July 26, 1844
• Death City: Manchester
• Death Country: United Kingdom

CITATION INFORMATION

• Article Title: John Dalton Biography
• Author: Biography.com Editors
• Website Name: The Biography.com website
• Url: https://www.biography.com/scientists/john-dalton
• Access Date:
• Publisher: A&E; Television Networks
• Last Updated: May 21, 2021
• Original Published Date: April 2, 2014
• Berzelius' symbols are horrifying. A young student in chemistry might as soon learn Hebrew as make himself acquainted with them.
• We might as well attempt to introduce a new planet into the solar system, or to annihilate one already in existence, as to create or destroy a particle of hydrogen.
• The principal failing in [Sir Humphrey Davy's] character as a philosopher is that he does not smoke.
• I can now enter the lecture room with as little emotion nearly as I can smoke a pipe with you on Sunday or Wednesday evenings.
• Matter, though divisible in an extreme degree, is nevertheless not infinitely divisible. That is, there must be some point beyond which we cannot go in the division of matter... I have chosen the word 'atom' to signify these ultimate particles.
• Will it not be thought remarkable that in 1836 the British chemists are ignorant whether attraction, repulsion or indifference is marked when a mixture of any proportions of azote and oxygen are made.
• In short, [London] is a most surprising place, and worth one's while to see once; but the most disagreeable place on earth for one of a contemplative turn to reside in constantly.
• To ascertain the exact quantity of water in a given quantity of air is, I presume, an object not yet fully attained.
• The cause of rain is now, I consider, no longer an object of doubt.

Famous British People

George Michael

What We Know About ‘The Crown’ Season 6

Michael Caine Has Never Seen His ‘Jaws’ Role

David Beckham

Get to Know David and Victoria Beckham’s Kids

All the Details on David and Victoria’s Love Story

Peter Sutcliffe

Rosemary West

Myra Hindley

Dennis Nilsen

• Scientific Biographies

John Dalton

The theory of atomism, proposed by Dalton in the early 19th century and derived from meteorological studies, is the foundation for our modern concept of the atom.

Although a schoolteacher, a meteorologist, and an expert on color blindness, John Dalton is best known for his pioneering theory of atomism. He also developed methods to calculate atomic weights and structures and formulated the law of partial pressures.

Dalton (1766–1844) was born into a modest Quaker family in Cumberland, England, and for most of his life—beginning in his village school at the age of 12—earned his living as a teacher and public lecturer. After teaching for 10 years at a Quaker boarding school in Kendal, he moved on to a teaching position in the burgeoning city of Manchester.

There he joined the Manchester Literary and Philosophical Society, which provided him with a stimulating intellectual environment and laboratory facilities. The first paper he delivered before the society was on color blindness, which afflicted him and is sometimes still called Daltonism.

Theories of Atomism and the Law of Partial Pressures

Dalton arrived at his view of atomism by way of meteorology, in which he was seriously interested for a long period: he kept daily weather records from 1787 until his death, his first book was Meteorological Observations (1793), and he read a series of papers on meteorological topics before the Literary and Philosophical Society between 1799 and 1801.

The papers contained Dalton’s independent statement of Charles’s law (see Joseph Louis Gay-Lussac ): “all elastic fluids expand the same quantity by heat.” He also clarified what he had pointed out in Meteorological Observations —that the air is not a vast chemical solvent as Antoine-Laurent Lavoisier and his followers had thought, but a mechanical system, where the pressure exerted by each gas in a mixture is independent of the pressure exerted by the other gases, and where the total pressure is the sum of the pressures of each gas.

In explaining the law of partial pressures to skeptical chemists of the day—including Humphry Davy —Dalton claimed that the forces of repulsion thought to cause pressure acted only between atoms of the same kind and that the atoms in a mixture were indeed different in weight and “complexity.”

Experiments on Atomic Weights and Structures

He proceeded to calculate atomic weights from percentage compositions of compounds, using an arbitrary system to determine the likely atomic structure of each compound. If there are two elements that can combine, their combinations will occur in a set sequence. The first compound will have one atom of A and one of B; the next, one atom of A and two atoms of B; the next, two atoms of A and one of B; and so on.

Hence, water is HO. Dalton also came to believe that the particles in different gases had different volumes and surrounds of caloric, thus explaining why a mixture of gases—as in the atmosphere—would not simply layer out but was kept in constant motion. Dalton consolidated his theories in his New System of Chemical Philosophy (1808–1827).

As a Quaker, Dalton led a modest existence, although he received many honors later in life. In Manchester more than 40,000 people marched in his funeral procession.

Featured image: Portrait print of Dr. John Dalton, F.R.S. , 1834. Science History Institute.

Browse more biographies

Eugene Houdry

Justus von Liebig

Ruth Benerito

Copy the above HTML to republish this content. We have formatted the material to follow our guidelines, which include our credit requirements. Please review our full list of guidelines for more information. By republishing this content, you agree to our republication requirements.

• Show navigation

You currently have JavaScript disabled in your web browser, please enable JavaScript to view our website as intended.

Here are the instructions of how to enable JavaScript in your browser.

John Dalton FRS

John Dalton (1766-1844) was an English chemist, physicist, and meteorologist, best known for introducing the atomic theory into chemistry and for his work on human optics. Inspired by his own unusual perception of colour, he conducted the first ever research into colour blindness – a subject which subsequently became known as Daltonism.

John Dalton was born in 1766, to a modest Quaker family from the Lake District in Cumbria. While he received little formal education, his sharp mind and natural sense of curiosity compensated for a lack of early schooling. At the age of just 12 he joined his older brother in running a local Quaker school, where he remained as a teacher for over a decade.

Dalton had two influential mentors during this time: Elihu Robinson, a rich intellectual with an interest in mathematics and science; and John Gough, a blind classics scholar and natural and experimental philosopher. Both these men inspired in Dalton an avid interest in meteorology that lasted for the rest of his life.

In 1793, Dalton published his first scientific paper: 'Meteorological Observations and Essays'. He was keen to pursue further atmospheric and weather research at an academic institution, but as a Quaker was barred from most British universities at the time, so his mentor Gough pulled a few strings and got him a place as a tutor at Manchester College.

A curious investigation

By the time he arrived in Manchester, Dalton had begun to realise that he saw the world differently from most other people, as he wrote in a letter to Elihu Robinson:

"I am at present engaged in a very curious investigation. I discovered last summer with certainty, that colours appear different to me to what they do to others. […] my brother excepted, who seems to see as I do."

Dalton's observation that he and his brother both shared such an anomaly led him to conclude that his unusual colour perception was the result of a hereditary condition. His account of this phenomenon to the Manchester Literary and Philosophical Society in 1794 is the first recorded description of colour blindness, or as it became known, Daltonism.

Over the following years, Dalton conducted extensive research on the subject, culminating in the publication of his 1798 paper, 'Extraordinary facts relating to the vision of colours', in which he proposed that his own colour blindness was the result of his vitreous humour (the jelly-like part of his eye) possessing an abnormal blue tint, thus acting as a filter for certain wavelengths of light. 

However, post-mortem examination of his eyes in 1844, performed upon his prior request, revealed their contents to be "perfectly colourless." It was not until 1995, when modern scientists conducted a DNA analysis of his preserved eyeball, that it was revealed he had what is known today as red-green colour blindness, or deuteranopia: a rare form of the condition caused by a missing gene for the receptor sensitive to medium wavelength (green) light (as opposed to deuteroanomaly, which involves a mutated form of pigment).

Gases and atoms

By the turn of the nineteenth century, the emergence of new experimental techniques enabled Dalton to expand on his early meteorological work; specifically, the absorption of water vapour by air at different temperatures. His subsequent work on the constitution, evaporation and thermal expansion of gases led to his derivation of Dalton’s law of partial pressures, which in turn informed his proposition in 1803 of the modern theory of the atom.

Dalton’s atomic theory suggested that all matter was comprised of indivisible and indestructible atoms with distinct masses and properties, the combination of which determined the physical nature of their constituent elements. While his proposals for some exact formulations were incorrect (he thought that the formula for water was OH, rather than H2O), his ideas were revolutionary and laid the foundations for the development of all modern chemistry.

It was for his work on atomic theory that in 1826, Dalton became one of the first two recipients of the Royal Medal, a prestigious award presented annually by the Royal Society for "the most important contributions to the advancement of natural knowledge."

A life dedicated to science

Dalton continued his scientific investigation into a wide range of subjects until his death in 1844. He remained an active member of the Manchester Literary and Philosophical Society and, from 1822, was a Fellow of the Royal Society; his election citation stated that his "talents, acquirements and exertions are well known to his fellow labourers in the cause of Science".

Sign up for newsletters

Local Histories

Tim's History of British Towns, Cities and So Much More

A Brief Biography of John Dalton

By Tim Lambert

His Early Life

John Dalton was a great scientist of the early 19th century. He is famous for his theory of atoms. Dalton was born on 6 September 1766 in Eaglesfield, Cumbria, England. His father, Joseph Dalton was a weaver. His mother was called Deborah and the couple had 4 children. John received an elementary education at a Quaker school but he was mainly self-taught. When he was only 10 Dalton entered the service of a Quaker called Elihu Robinson.

But when he was just 12 Dalton set up his own school. However, his school failed. Dalton then joined his brother Jonathan as an assistant at a school in Kendal. Meanwhile, Dalton had a passion for science and he studied the subject enthusiastically.

Then in 1793 Dalton was offered a position as a professor of mathematics and philosophy at Manchester Academy. The same year, 1793 he published his first work, Meteorological Reflections, And Essays.

The Great Scientist

Dalton joined the Manchester Literary and Philosophical Society. In 1794 he read them a paper on colour blindness, which for a long time was called Daltonism after him. However, by 1800 the academy was in financial trouble. Dalton left and began earning a living as a private tutor in mathematics and science.

Meanwhile, he investigated gases and in 1803 he published his law of partial pressures. Then, in 1808 Dalton published his great work A New System of Chemical Philosophy in which he stated his atomic theory.

In 1832 Dalton was granted an honorary degree by Oxford University. Then in 1833, he was granted a pension from the British government. At first, it was a modest amount (150 pounds a year) but it was doubled to 300 pounds in 1836. John Dalton died on 27 July 1844. He was buried in Ardwick Cemetery in Manchester. 

There is a crater on the Moon named after Dalton.

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)
• Click to share on LinkedIn (Opens in new window)
• Click to share on WhatsApp (Opens in new window)

{{ message }}

{{ addToCartData.mixPtRmWarning }}

Souhaitez-vous continuer ?

{{requestquote.productname}}; {{requestquote.form.productcode}}.

{{ errors.first('firstName') }}

{{ errors.first('lastName') }}

{{ errors.first('email') }}

{{ errors.first('company') }}

{{ errors.first('packSize') }}

{{ errors.first('quantity') }}

Nous répondrons à votre demande dans les plus brefs délais.

Something went wrong, please try again later.

Votre panier est actuellement vide.

Connectez-vous pour voir les prix et procéder au paiement

Notez que les frais de livraison et les taxes sont calculés sur la page de paiement.

{{entry.product.manufacturer}}

{{entry.product.name}}.

Code du produit   {{entry.product.displayPartCode ? entry.product.displayPartCode : entry.product.code}}

CAS: {{entry.product.casNumber}}

Pack size: {{entry.product.uom}}

Niveau de biosécurité La classification de biosécurité s'appuie sur les directives du service de santé publique des États-Unis . Il incombe au client de s'assurer du respect intégral de toutes les réglementations applicables en matière de biosécurité et de biomatériaux dans son pays. : {{entry.product.biosafetyLevel == -1 ? '-' : entry.product.biosafetyLevel}} Code douanier {{entry.product.euTariffCode}}

{{ service.name }}

• Brazil ( Anglais )  |  ( Portugais (Brésil) )
• China Mainland ( Anglais )  |  ( Chinois (simplifié) )
• France ( Anglais )  |  ( Français )
• Germany ( Anglais )  |  ( Allemand )
• Italy ( Anglais )  |  ( Italien )
• Mexico ( Anglais )  |  ( Espagnol )
• Netherlands
• Poland ( Anglais )  |  ( Polonais )
• South Korea
• Spain ( Anglais )  |  ( Espagnol )
• Switzerland ( Anglais )  |  ( Allemand )  |  ( Français )
• United Kingdom
• United States of America (USA)
• Aide et support
• Nous contacter

Veuillez vous connecter ou vous enregistrer pour ajouter des éléments à vos favoris

Ou continuez à naviguer, mais vous ne pourrez avoir accès aux favoris ou aux tarifs.

Veuillez vous connecter pour voir les prix et ajouter au panier

Ou continuez à naviguer pour voir les étapes accessibles sans information de prix

Si vous n'avez pas encore de compte, veuillez  créer un compte créer un compte

John Dalton – the Father of Modern Chemistry

More than 200 years ago, a teacher from the North West of England was drafting a leaflet to publicise his new science book. His intention , he wrote, was “to place the whole science of Chemistry upon a new, and more simple, basis than it has been upon heretofore,” and it’s safe to say this wasn’t just hyperbole. The writer was John Dalton – born 255 years ago today, on September 6, 1766 – and his 1808 work, New System of Chemical Philosophy, was about to usher chemistry into the modern age. 

Dalton’s work first established what science historian Arnold Thackray says is now “ one of the most familiar ideas in the world ” - that all matter is made up of tiny, indivisible particles called atoms.

The self-taught Dalton, who came to chemistry by way of meteorological observations in his rain-swept, native Cumberland, also gave the world several more big ideas that together made up his atomic theory :  

1. Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements.

2. Atoms cannot be subdivided, created or destroyed.

3. Atoms of different elements can combine in fixed, whole number ratios to form compounds.

4. Atoms of the same element can combine in more than one ratio.

5. In chemical reactions, atoms are combined, separated or rearranged.

6. The atom is the smallest unit of matter that can take part in a chemical reaction. 

In the book, Dalton also drew individual atoms and compound atoms for the first time – a breakthrough that still forms the basis of how chemists visualise elements and molecules today, as well as the notation that they use. 

“For the first time ever, we’ve suddenly got a language, a way of thinking about it, a set of formulae that advance chemistry tremendously,” Thackray says . “And from that day to this, chemistry’s been done on that basis.”  

Of course, Dalton’s atomic theory was not without its flaws – and its critics. For many scientists, the fact that he could not confirm it by direct observation – because atoms could not be seen – was problematic. Amongst those who remained unconvinced were Sir Humphry Davy (1778-1829) and the leading French chemist, Claude-Louis Berthollet (1748-1822). However, whether proven or not, atomic theory proved useful because it was simpler to express the stoichiometry of a chemical reaction in atoms rather than absolute mass , while organic chemistry in particular made rapid advances once Dalton’s ideas were accepted. “Many chemists found themselves using atomic theory,” Marc Michalovic writes , “even if they held their noses all the while.” 

Although Dalton is regarded as the first proponent of modern atomic theory, the idea that matter is comprised of minute particles has a long and brilliant – although not always acknowledged – history. Dalton’s breakthrough was heavily influenced by the work of French scientists Antoine Lavoisier (1743-1794) and Joseph Proust (1754-1826), but some philosophers were exploring the concept long before that: 

c800-600 BCE

Unknown to western scientists in Dalton’s time, an Indian philosopher’s son called Acharya Kanada first conceptualised the idea of indivisible matter (the ‘ anu ’) around 2,500 years earlier - after breaking the food in his hand into smaller and smaller pieces until he was left with just its smell. 

c460-370 BCE

The Greek philosopher Democritus first used the term ‘ atomos ’, meaning ‘uncuttable’ , to describe the tiny, unbreakable objects that he suggested made up all matter in the universe. 

Antoine Lavoisier’s law of conservation of matter stated that in any system that is closed to the transfer of matter – both in and out – the amount of matter is conserved. Therefore, during any physical or chemical change, the total mass of the products remains equal to the total mass of the reactants. 

Proust, meanwhile, developed the law of definite proportion , which demonstrates that, if a compound is broken down into its constituent elements, the masses of the constituents will always have the same proportions, regardless of the quantity or source of the original substance.  

Dalton’s atomic theory informed the later experimental work of the Swedish chemist Jöns Jacob Berzelius (1779-1848). Berzelius further explored definite proportions, exploring the composition of elements and compounds through the combining properties of all known chemicals, and establishing a table of relative atomic weights in 1818. He also updated Dalton’s system of chemical notation, developing the system still in use today, although we have now swapped his superscript numbers (eg H 2 O) for subscript (H 2 O).  

Although some key aspects of Dalton’s work have been contradicted over time – for example, by the discovery of electrons , isotopes and allotropes – his atomic theory remains an astonishing achievement. Nature thinks it “perhaps the greatest” step on a long road of understanding, stretching from the ancients to Rutherford and Bohr in the 20 th Century. No wonder that many still consider this “ modest teacher ” excluded from Oxford and Cambridge because of his Quaker beliefs to be the father of modern chemistry , more than 250 years after his birth.  

Votre session Punchout va expirer dans 1 min 59 sec

Sélectionnez “continuer la session” pour prolonger la session