Robert Boyle

Boyle was a leading intellectual figure of the 17th century and one of the founders of modern chemistry.

Robert Boyle was born on 27 January 1627 in County Waterford in the south-east of Ireland. He was the seventh son of the earl of Cork. He was educated at Eton and then travelled and studied in Europe. He returned from the continent in 1644 extremely interested in science and settled in Dorset where he built a laboratory. In 1655 or 1666, Boyle moved to Oxford. It was here that he engaged Robert Hooke as an assistant and together they devised the most famous piece of experimental equipment associated with Boyle, the vacuum chamber or air-pump.

At this time even the idea of an experiment was controversial. The established method of 'discovering' something was to argue it out, using the established logical rules Aristotle and others had worked out 2,000 years before. Boyle was more interested in observing nature and drawing his conclusions from what actually happened. He was the first prominent scientist to perform controlled experiments and publish his work with details concerning procedure, apparatus and observations. He began to publish in 1659 and continued to do so for the rest of his life on subjects as diverse as philosophy, medicine and religion.

It is Boyle's Law for which he remains most famous. This states that if the volume of a gas is decreased, the pressure increases proportionally. Understanding that his results could be explained if all gases were made of tiny particles, Boyle tried to construct a universal 'corpuscular theory' of chemistry. He defined the modern idea of an 'element', as well as introducing the litmus test to tell acids from bases, and introduced many other standard chemical tests.

In 1660, together with 11 others, Boyle formed the Royal Society in London which met to witness experiments and discuss what we would now call scientific topics.

In 1668, Boyle moved permanently to London, living with his sister. In 1680 he refused the presidency of the Royal Society because the oath required violated his strongly held religious principles. Boyle died in London on 31 December 1691.

http://www.bbc.co.uk/history/historic_figures/boyle_robert.shtml

Henry Cavendish

Cavendish, often referred to as “the Honourable Henry Cavendish,” had no title, although his father was the third son of the duke of Devonshire, and his mother (née Ann Grey) was the fourth daughter of the duke of Kent. His mother died in 1733, three months after the birth of her second son, Frederick, and shortly before Henry’s second birthday, leaving Lord Charles Cavendish to bring up his two sons. Henry went to the Hackney Academy, a private school near London, and in 1748 entered Peterhouse College, Cambridge, where he remained for three years before he left without taking a degree (a common practice). He then lived with his father in London, where he soon had his own laboratory.

About the time of his father’s death, Cavendish began to work closely with Charles Blagden, an association that helped Blagden enter fully into London’s scientific society. In return, Blagden helped to keep the world at a distance from Cavendish. Cavendish published no books and few papers, but he achieved much. Several areas of research, including mechanics, optics, and magnetism, feature extensively in his manuscripts, but they scarcely feature in his published work.

His first publication (1766) was a combination of three short chemistry papers on “factitious airs,” or gases produced in the laboratory. He produced “inflammable air” (hydrogen) by dissolving metals in acids and “fixed air” (carbon dioxide) by dissolving alkalis in acids, and he collected these and other gases in bottles inverted over water or mercury. He then measured their solubility in water and their specific gravity and noted their combustibility. Cavendish was awarded the Royal Society’s Copley Medal for this paper. Gas chemistry was of increasing importance in the latter half of the 18th century and became crucial for Frenchman Antoine-Laurent Lavoisier’s reform of chemistry, generally known as the chemical revolution.

http://www.britannica.com/EBchecked/topic/100664/Henry-Cavendish

Joseph Priestley

Ever had a sip of soda and marvelled at the fact how a little fizz makes it different from fruit juices? Joseph Priestley added fizz in our life with the discovery of soda water and oxygen.

Today everyone knows oxygen is essential for us to breathe. People, animals and plants all need this gas to live. Joseph Priestley was the first person to discover oxygen. He also invented soda water, the substance that makes soft drinks so fizzy.

The early yearsPriestley was the eldest of six children from an English family. He spent his early years living with his grandfather. After his mother died when he was just six years old, in1741 he went to live with his aunt and uncle, Sarah and John Keighley, who educated him. In 1749 he became ill, which left him with a constant stutter. Ten years later Priestley started a school in Nantwich Cheshire. Here, he wrote a book on English grammar.

An electrifying discoveryDocumenting the history of electricity was Priestley’s first scientific work. He met many famous experimenters including John Canton, William Watson and Benjamin Franklin. He became so interested that he started his own experiments in electricity. Priestley discovered certain substances like charcoal that conducted electricity. This changed the belief that only water and liquids were good conductors of electricity. His book on the history of electricity became standard for over a century.

Soda waterWhen James Cook was to set sail on his second South Sea voyage, Joseph Priestley showed sailors how to create soda water. He thought this would cure Scurvy - a disease caused by lack of Vitamin C, common in sailors. Priestley discovered how to infuse water with carbon dioxide by suspending a bowl of water over a beer vat. He later experimented how to create carbon dioxide gas and infuse it in agitated water.

Experiments on airs and the discovery of oxygen

In 1744, Priestley conducted experiments on isolating air and discovered a new gas. Originally called dephlogisticated air, it was later named oxygen. He produced this by focusing suns rays on mercuric oxide. The reaction that resulted produced oxygen. Priestley’s experiments in air also lead to several discoveries, including nitric oxide, anhydrous hydrochloric acid, ammonia and nitrous oxide.

Studies in photosynthesis

Priestley’s studies and experiments in air also lead to the first discovery of photosynthesis. He showed how a burning candle in an inverted jar used up air and how keeping a plant in that jar could then produces oxygen by photosynthesis.

The American dream

When he was 61 years old, Joseph Priestley moved to America. Here he was welcomed as a contemporary thinker and friend. He was a supporter of both the American and French revolutions.

Antoine-Laurent de LavoisierFew things are as important as water, which we know is made of oxygen and hydrogen. Did you know that Antoine Lavoisier was the discoverer of both elements?

Contributions to Science

Antoine-Laurent de Lavoisier is one of the most important scientists in the history of chemistry. He discovered elements, formulated a basic law of chemistry and helped create the metric system.

During his time, people believed that when an object burns, a mysterious substance called ‘phlogiston’ was released. This was called the ‘phlogiston theory’. Lavoisier’s experiments demonstrated the contrary, i.e. when something burned, it actually absorbed something from the air, instead of releasing anything. He later named the ‘something’ from the air as oxygen, when he found that it combined with other chemicals to form acid. (In Greek, ‘oxy’ means sharp, referring to the sharp taste of acids.)

Henry Cavendish had earlier isolated hydrogen, but he called it inflammable air. Lavoisier showed that this inflammable air burned to form a colourless liquid, which turned out to be water. The Greek word for water is ‘hydro’, so the air that burned to form water was hydrogen!

Lavoisier was known for his painstaking attention to detail. Whenever he made a chemical reaction, he weighed all the substances carefully before and after the reaction. He discovered that in a chemical reaction, though substances may change their chemical nature, their total mass remains the same. This is called the law of conservation of mass.

His love for accuracy led to the formulation of the metric system of weights and measures – which is still in use today.

Lavoisier’s attention to detail and habit of recording everything is perhaps his most important contribution – for that is now the way science is done.BiographyLavoiser was born on 26 August 1743 in a wealthy Parisian family. He studied at the Collège Mazarin from 1754 to 1761. His interest in chemistry was developed as he read the works of Étienne Condillac. In 1769, he set about making a geological map of France, which was important for that country’s industrial development. In 1769, he took a government position as a tax collector in the government of King Louis XVI.

In 1771, he married Marie-Anne Pierette Paulze, who is considered as an eminent scientist in her own right.

She translated the works of many scientists from English and German into French, and later on, with her husband, published the Traité élémentaire de chimie, often considered the first comprehensive book on the subject.

In 1789, King Louis XVI was overthrown in the French Revolution. As Lavoisier had been a tax collector, he earned the wrath of the revolutionaries, who executed him on 8 May 1794.http://humantouchofchemistry.com/antoinelaurent-de-lavoisier.htm

John DaltonBest-known for his work in modern atomic theory, John Dalton was an English chemist, meteorologist and physicist. The son of a weaver, Dalton's major contribution to the field of chemistry is his atomic theory proposed in 1803. In the theory he reasoned that tiny particles called atoms make up elements.

Early beginnings

Though he came from a family of shoemakers and weavers, Dalton earned his living as a lecturer. Even at a young age he was interested in metrology and would spend time learning how to use metrological instruments and taking periodic readings. In fact, it was Dalton's work in this field that turned what was considered by many to be folklore into a respectable science.

Dalton's atomic theory

In his famous atomic theory, Dalton stated that tiny particles called atoms form elements. Different elements would have atoms of different sizes and mass. According to him atoms were unique, as they couldn't be created, divided or destroyed by chemical process. The later discovery of nuclear fusion and nuclear fission altered this viewpoint, though these were nuclear and not chemical reactions. The discovery of isotopes subsequently proved that elements can be identical in chemical structure but different in weight.

Understanding the atom

Atoms of a same element are always identical. He went on to prove that atoms of different elements could be differentiated by their atomic number. Atoms of different elements combine to form compounds. Compounds are unique, having a specific relative number of atoms. Dalton's theory was the important first step towards modern atomic theory.

The colourful truth about colour blindness

Dalton's theory on colour-blindness was one of the first researches published. Being the first person to research this, colour-blindness was known as Daltonism. He had made this important discovery when he realised that his own brother was colour-blind. Though his theory; that colour perception was by the discolouration of the liquid medium in the eyeball was disproved during his lifetime, it was the first time that this problem was formally discussed. John Dalton also held the view the atmosphere was a mixture of gasses. He believed the main ingredients were a mixture of 80% nitrogen and 20% oxygen.

http://humantouchofchemistry.com/john-dalton.htm

Brown, Robert (1773-1858), a Scottish botanist, is best known for describing the agitation of microscopic particles suspended in a liquid or gas, a movement that is now called Brownian motion.

Robert Brown, the son of an Episcopalian minister, completed his medical studies at the University of Edinburgh and then worked as an assistant surgeon in a Scottish infantry regiment. In the late 1790's, he met well-known botanist Joseph Banks and began to pursue his interest in botany. After resigning his surgical post, Brown served from 1801 to 1805 as the naturalist on an expedition to survey the coast of Australia, which had been recently discovered by Europeans. From 1810 until Banks's death in 1820, Brown served as his librarian. In 1827, Banks's books and collections were transferred to the British Museum, where Brown became curator of the botanical department.

Brown had noted and studied the agitated motion of very fine pollen grains suspended in water. In 1828, his observations of this motion were published. Brown also established that tiny particles of inorganic materials such as carbon and metals display Brownian motion. Brownian motion proved important to the development of the atomic theory of matter, which states that matter is composed of small particles in random motion.

Among his other contributions, Brown gave the name nucleus to the specialized body that regulates the functions of a living cell and was the first to identify it as a feature of most living cells. In addition to naming

the world's largest flower—the giant rafflesia of Sumatra, which can grow more than 3 feet (91 centimeters) wide— Brown also began the study of plant fossils, using a microscope.

http://science.howstuffworks.com/dictionary/famous-scientists/biologists/robert-brown-info.htm

X-rays are a form of electromagnetic radiations which emitted when matter is bombarded with fast electrons.

Wilhelm Conrad Roentgen

Wilhelm Roentgen, a German professor of physics, was the first person to discover electromagnetic radiation in a wavelength range commonly known as X-rays today. Although, many people had observed the effects of X-ray beams before, but Roentgen was the first one to study them systematically. To highlight the unknown nature of his discovery, he called them X-rays though they are still known as Roentgen-rays as well. For his remarkable achievement he was honored with the first he first Nobel Prize in Physics in 1901.

Discovery of X-ray BeamsWilhelm Roentgen was already working on the effects of cathode rays during 1895, before he actually discovered X-rays. His experiments involved the passing of electric current through gases at extremely low pressure. On November 8, 1895 while he was experimenting, he observed that certain rays were emitted during the passing of the current through discharge tube. His experiment that involved working in a totally dark room with a well-covered discharge tube resulted in the emission of rays which illuminated a barium platinocyanide

covered screen. The screen became fluorescent even though it was placed in the path of the rays, two meters away from discharge tube.

He continued his experiments using photographic plate to capture the image of various objects of random thickness placed in the path of the rays. He generated the very first "roentgenogram" by developing the image of his wife's hand and analyzed the variable transparency as showed by her bones, flesh and her wedding ring. Based on his subsequent research and experiments, he declared that X-ray beams are produced by the impact of cathode rays on material objects.

http://explorable.com/wilhelm-conrad-roentgen

Antoine Henri Becquerel

Let's read about how the field of nuclear chemistry was born!

Antoine Henri Becquerel (1852-1908)

It was the month of February in the year of 1896. Antoine Henri Becquerel, a French scientist, was conducting an experiment which started with the exposure of a uranium-bearing crystal to sunlight. Once the crystal had sat in the sunshine for a while, he placed it on a photographic plate. As he had anticipated, the crystal produced its image on the plate. Becquerel theorized that the absorbed energy of the sun was being released by the uranium in the form of x-rays.

Further testing of this theory had to be put off for a few days because the sky had clouded up and the sun had disappeared. For the next couple of days he left his sample of uranium in a closed drawer along with the photographic plate.

When the weather had cleared, he returned to the drawer to retrieve his gear. He was surprised to find that the crystal had left a clear, strong image on the photographic plate.

How could this be? There was no source of energy to produce the image! What Becquerel had discovered was that a piece of mineral which contained uranium could produce it's image on a photographic plate in the absence of light. What he had discovered was radioactivity! He attributed this phenomenon to spontaneous emission bt the uranium.

http://www.chem.duke.edu/~jds/cruise_chem/nuclear/discovery.html

The scientist who made Brownian motion famous is Albert Einstein, who brought the phenomenon to the attention of the larger physics community by publishing a paper on it in 1905, his personal annus mirabilis or "wonderful year." The phenomenon was observed as early as 1765, but not described or studied in detail until the botanist Robert Brown's research in 1827,and it is named in honor of his work. As a botanist, Brown first observed the effect in pollen floating in water, where it is visible with the naked eye. Through experimentation, Brown determined that the specks of pollen were not propelling themselves independently, but rather that their motion was psuedo-random.

Brownian motion is a phenomena whereby small particles suspended in a liquid tend to move in psuedo-random or stochastic paths through the liquid, even if the liquid in question is calm. It is the result of asymmetry in the kinetic impacts of molecules that make up the liquid. The liquid phase, by definition, must have some temperature, meaning its molecules or atoms must be thermally excited, bumping into each other and objects suspended within them. To picture this phenomena, a person can imagine the motion of golf balls on a table filled with thousands of ball bearings moving in quick trajectories.

http://www.wisegeek.com/what-is-brownian-motion.htm

Marie Curie

Famous Marie Curie quotes include: “We must not forget that when radium was discovered no one knew that it would prove useful in hospitals. The work was one of pure science. And this is a proof that scientific work must not be considered from the point of view of the direct usefulness of it. It must be done for itself, for the beauty of science, and then there is always the chance that a scientific discovery may become like the radium a benefit for humanity.”

Marie Curie

Marie Curie was a chemist and physicist famous for becoming the first person to be awarded two Nobel Prizes. She was brought up in Poland before eventually moving to France and obtaining French citizenship.

After French physicist Henri Becquerel first discovered a strange source of energy coming from uranium (radioactivity), Marie Curie decided that this would make a good field for research. With the help of her husband and his vital electrometer, she made numerous scientific discoveries including showing that radiation did indeed come from the atom itself rather than an interaction between molecules.

In 1911 Marie Curie was awarded another Nobel Prize, this time in Chemistry, for her discovery of radium and polonium and subsequent research.

In 1932 Marie Curie founded the ‘Radium Institute’ in Warsaw, Poland. The name was changed after World War II to the ‘Maria Skłodowska-Curie Institute of Oncology’. The institute carries out specialized cancer research and treatment.

http://www.sciencekids.co.nz/sciencefacts/scientists/mariepierrecurie.html

Ernest Rutherford was a New Zealand chemist who helped pioneer nuclear physics. He won a Nobel Prize in chemistry, made numerous contributions to science and worked closely with a number of his students who went on to make their own significant discoveries. Read on for interesting facts, quotes and information about Ernest Rutherford.

Ernest Rutherford lived from the 30th of August 1871 to the 19th of October 1937.

Rutherford studied at Canterbury College, University of New Zealand before moving to England in 1895 for post graduate study at

Cavendish Laboratory, University of Cambridge.

Rutherford worked on radioactivity, coining the terms ‘alpha’ and ‘beta’ to describe the two different types of radiation emitted by uranium and thorium. He also observed that radioactive material took the same amount of time for half of it to decay, known as its “half life”.

In 1907, Rutherford, Hans Geiger and Ernest Marsden carried out the Geiger-Marsden experiment, an attempt to examine the structure of the atom. The surprising results of this experiment demonstrated the existence of the atomic nucleus and became an integral part of the Rutherford model of the atom.

The Rutherford model of the atom was simplified in a well-known symbol showing electrons circling around the nucleus like planets orbiting the sun. This symbol became popular and has been used by various organizations around the world as a symbol for atoms and atomic energy in general.

http://www.sciencekids.co.nz/sciencefacts/scientists/ernestrutherford.html

English physicist Henry Moseley, who arranged the Periodic Table in order of the atomic numbers of the elements.

ENGLISH PHYSICIST 1887–1915

Henry Moseley's research career lasted only forty months before tragically ending with his death on a Gallipoli battlefield in World War I. But in his classic study of the x-ray spectra of elements, he established the truly scientific basis of the Periodic Table by arranging chemical elements in the order of their atomic numbers.

Henry Gwyn Jeffreys Moseley, who was always called "Harry" by his family, was born in Weymouth, England, on November 23, 1887. His family was wealthy, aristocratic, and scientifically accomplished, and young Henry showed an early interest in zoology . He attended Eton on a King's scholarship, where he excelled in mathematics, and was introduced to the study of x rays by his physics teacher. He entered Trinity College, Oxford, in 1906. At that time, Oxford did not have a particularly notable science curriculum, but Moseley chose the school in order to be near his widowed mother. He graduated in 1910 with high honors in mathematics and science, and secured a position in the laboratory of Ernest Rutherford at the University of Manchester.

It was a time of great excitement and ferment in science, and Rutherford's laboratory was one of the epicenters of discovery in atomic physics. The first coherent theory of the structure of the atom was just then being developed by Rutherford and his research group, which, besides Moseley, included Niels Bohr, Hans Geiger, Kasimir Fajans, and others.

The nature of x rays was also receiving new interest because of the discovery by the German physicist Max von Laue in 1912 that they were diffracted by their passage through crystals and therefore possessed a wave nature. Succeeding experiments by William L. Bragg the same year showed that similar results could be obtained by the reflection of x rays from the face of a crystal. Moseley persuaded Rutherford to allow him and a colleague, C. S. Darwin, to further study the nature of x rays. Their work demonstrated that the spectral line of platinum, which they were using as the anticathode in their x-ray tube, was characteristic of that element alone. Moseley returned to Oxford, and despite the experimental deficiencies of his laboratories, measured the x-ray spectral lines of nearly all the elements from aluminum to gold. The results of his study showed a clear and simple progression of the elements that was based on the number of protons in the atomic nucleus, rather than the order based on atomic weights that was then the basis of the Periodic Table.

http://www.chemistryexplained.com/Ma-Na/Moseley-Henry.html#ixzz2d1xh6kdz

Johannes Bronsted and Thomas Lowry

In 1923, within several months of each other, Johannes Nicolaus Brønsted (Denmark) and Thomas Martin Lowry (England) published essentially the same theory about how acids and bases behave. Since they came to their conclusions independently of each other, both names have been used for the theory name.

Brønsted–Lowry theory, also called proton theory of acids and bases, a

theory, introduced independently in 1923 by the Danish chemist Johannes Nicolaus Brønsted and the English chemist Thomas Martin Lowry, stating that any compound that

can transfer a proton to any other compound is an acid, and the compound that accepts the proton is a base. A proton is a nuclear particle with a unit positive electrical charge; it is represented by the symbol H+ because it constitutes the nucleus of a hydrogen atom

The Brønsted–Lowry theory enlarges the number of compounds considered to be acids and

bases to include not only the neutral molecules (e.g., sulfuric, nitric, and acetic acids, and the alkali metal hydroxides) but also certain atoms and molecules with positive and negative electrical charges (cations and anions). The ammonium ion, the hydronium ion, and some

hydrated metal cations are considered acids. The acetate, phosphate, carbonate, sulfide, and halogen ions are considered bases.

http://www.britannica.com/EBchecked/topic/80953/Bronsted-Lowry-theory

On December 2, 1942, Enrico Fermi and his team of scientists harnessed the atom and opened the door to new scientific and technological realms. His achievement allowed the U.S. to produce the atomic bomb that helped end World War II. Now, more than fifty years later, nuclear energy provides a significant part of the world's

electrical power, and radioactive materials are used for hundreds of industrial, agricultural, and medical applications-from food preservation to cancer therapy, checking the integrity of welds in pipelines and bridge supports, and gauges that measure the thickness of coatings applied to paper.

Fermi was born in Rome in 1901 and received his doctorate from the University of Pisa in 1922. During 1923 to 1924, he studied in Göttingen, Germany, with Max Born, and in Leiden, The Netherlands, with Paul Ehrenfest. From 1924 to 1926, Fermi lectured in mathematical physics and mechanics at the University of Florence. He became the first professor of theoretical physics at the University of Rome, where he taught for 12 years.

http://science.energy.gov/fermi/the-life-of-enrico-fermi/