André-Marie Ampère

(20 January 1775 – 10 June 1836)

André-Marie Ampère is generally regarded as one of the main founders of classical electromagnetism. The SI unit of measurement of electric current, the ampere, is named after him.

Ampère developed a mathematical and physical theory to understand the relationship between electricity and magnetism, discovering that two parallel wires carrying electric currents attract or repel each other, depending on whether the currents flow in the same or opposite directions.

Ampère also theorised upon the existence of an ‘electrodynamic molecule’ that served as the component element of both electricity and magnetism. This was later discovered and is known today as the electron.

Archimedes of Syracuse

(c. 287 BC – c. 212 BC)

Archimedes of Syracuse was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an explanation of the principle of the lever. He is credited with designing innovative machines, including siege engines and the screw pump that bears his name.

Archimedes used the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, and gave a remarkably accurate approximation of pi. He also defined the spiral bearing his name, formulae for the volumes of solids of revolution, and an ingenious system for expressing very large numbers.

Ernst Otto Beckmann

(4 July, 1853 – 12 July, 1923)

Ernst Otto Beckmann was a German chemist who is remembered for his invention of the Beckmann differential thermometer and for his discovery of the Beckmann rearrangement.

After a year of voluntary military service, as a pharmacist, Beckmann began studying toxicology at the TU Braunschweig with Robert Otto. Beckmann tried to apply an already-known reaction to discriminate between aldehydes and ketones. The reaction involved the use of hydroxylamine to convert benzophenone into an oxime. Treating this oxime with phosphorus pentachloride converted it into a substance already characterised by Wallach. This reaction is now known as the Beckmann rearrangement.

Robert Boyle

(25 January 1627 – 31 December 1691)

Robert Boyle was a natural philosopher, chemist, physicist, and inventor. Regarded today as the first modern chemist, he is best known for Boyle's law, which describes the inversely proportional relationship between the absolute pressure and volume of a gas, providing the temperature is kept constant within a closed system.

Boyle was born in Lismore Castle, in County Waterford, Ireland, the son of an Earl, and received private tutoring in Latin, Greek and French before being sent to Eton College in England. He later travelled, then went on to devote his life to scientific research, taking a prominent place in the group known as the ‘Invisible College’, who devoted themselves to the growth of the ‘new philosophy’.

Anders Celsius

(27 November 1701 – 25 April 1744)

Anders Celsius was a Swedish astronomer who went on to become a professor of astronomy at Uppsala University.

He proposed the Celsius temperature scale in a paper to the Royal Society of Sciences in Uppsala, the oldest Swedish scientific society, founded in 1710. His thermometer was calibrated with a value of 100° for the freezing point of water and 0° for the boiling point.

Celsius was the first to suggest a connection between the aurora borealis and changes in the magnetic field of the Earth. At Nuremberg in 1733 he published a collection of 316 observations of the aurora borealis made by himself and others. In astronomy, Celsius began the first attempt to measure the magnitude of starlight with a tool other than the human eye.

Jacques Alexandre César Charles

(12 November 1746 – 7 April 1823)

Jacques Alexandre César Charles was a French inventor, scientist, mathematician and balloonist.

Jacques Charles and the Robert brothers launched the world’s first hydrogen filled balloon on 27 August 1783, from the Champ de Mars (now the site of the Eiffel Tower). It was filled with hydrogen that had been made by pouring a quarter of a tonne of sulphuric acid onto half a tonne of scrap iron. This gas was fed into the balloon via lead pipes.

Charles’ law (also known as the law of volumes) describes how gases expand when heated. It was first published by natural philosopher Joseph Louis Lussac in 1802, but he credited it to unpublished work by Jacques Charles, and named the law in his honour. Charles’ Law states that under constant pressure, the volume of an ideal gas is proportional to its absolute temperature. The volume of a gas at constant pressure increases linearly with the absolute temperature of the gas.

Charles-Augustin de Coulomb

(14 June 1736 – 23 August 1806)

Charles-Augustin de Coulomb was best known for developing Coulomb's law, the definition of the electrostatic force of attraction and repulsion.

He discovered an inverse relationship of the force between electric charges and the square of its distance, later named after him as Coulomb's law.

Coulomb also stated that the attractive force between two oppositely charged spheres is proportional to the product of the quantities of charge on the spheres and is inversely proportional to the square of the distance between the spheres. The SI unit of electric charge, the coulomb, was named after Coulomb.

John Dalton

(6 September 1766 – 27 July 1844)

John Dalton was an English chemist, meteorologist and physicist. He is best known for his pioneering work in the development of modern atomic theory, and his research into colour blindness (sometimes referred to as Daltonism, in his honour).

In 1801, Dalton presented an important series of papers: on the constitution of mixed gases; on the pressure of steam and other vapours at different temperatures, both in a vacuum and in air; on evaporation; and on the thermal expansion of gases.

The most important of all Dalton's investigations are those concerned with the atomic theory in chemistry, with which his name is inseparably associated.

René Descartes

(31 March 1596 – 11 February 1650)

René Descartes was a French philosopher, mathematician, and writer. Descartes' influence in mathematics is also apparent, with the Cartesian coordinate system having been named after him.

One of Descartes' most enduring legacies was his development of Cartesian or analytic geometry, which uses algebra to describe geometry. He started the convention of representing unknowns in equations by x, y, and z, and knowns by a, b, and c and was also first to use superscripts to show powers or exponents, for example the 2 used in x² to indicate squaring. He was also the first to assign a place for algebra in our system of knowledge, and believed that algebra was a method to automate or mechanise reasoning, particularly about abstract, unknown quantities.

Thomas Alva Edison

(11 February 1847 – 18 October 1931)

Thomas Alva Edison was an American inventor and businessman. Edison is the fourth most prolific inventor in history, holding well over 1,000 US patents in his name, as well as many patents elsewhere.

Edison began his career as an inventor in Newark, New Jersey, with the automatic repeater and his other improved telegraphic devices, but is remembered most for inventing the phonograph in 1877.

He did not invent the first electric light bulb, but instead invented the first commercially practical incandescent light. These early bulbs had an extremely short lifespan, cost a lot to produce and run, making them difficult to apply on a large scale commercially. The first successful test was on October 22, 1879, in which a bulb lasted 13.5 hours, but he later improved this with a filament that could last over 1,200 hours.

The key to Edison's fortunes was telegraphy though. He patented the sound recording and reproducing phonograph in 1878, and was also granted a patent for the motion picture camera or ‘Kinetograph’.

Michael Faraday

(22 September 1791 – 25 August 1867)

Michael Faraday was an English scientist whose main discoveries include electromagnetic induction, diamagnetism and electrolysis.

Faraday discovered two new compounds of chlorine and carbon, and also conducted the first rough experiments on the diffusion of gases. He invented an early form of what was to become the Bunsen burner, discovered chemical substances such as benzene and established that gases are the vapours of liquids possessing a very low boiling point. Faraday is also known for discovering the laws of electrolysis, and for terminology such as anode, cathode, electrode, and ion.

His inventions of electromagnetic devices formed the foundation of electric motor technology, and it was largely due to his efforts that electricity became used in technology.

The SI unit of capacitance, the farad, is named in his honour.

Sir John Ambrose Fleming

(29 November 1849 – 18 April 1945)

Sir John Ambrose Fleming FRS (29 November 1849 – 18 April 1945) was the English electrical engineer and physicist best known for inventing the vacuum tube.

Fleming was a consultant to the Marconi Wireless Telegraph Company, Swan Company, Edison Telephone, and later the Edison Electric Light Company. In 1899 he became Scientific Adviser to the Marconi Company and soon after began work on designing the power plant to enable the Marconi Company to transmit across the Atlantic.

In 1904 he invented the two-electrode vacuum-tube rectifier for which he is best known. This invention is often considered to have been the beginning of electronics, and Fleming's diode was used in radio receivers and radars for many decades afterwards.

Joseph Louis Gay-Lussac

(6 December 1778 – 9 May 1850)

Joseph Louis Gay-Lussac was a French chemist and physicist. He is known mostly for two laws related to gases, and for his work on alcohol-water mixtures, which led to the degrees Gay-Lussac used to measure alcoholic beverages in many countries.

In 1802, he was appointed demonstrator to A. F. Fourcroy at the École Polytechnique, where in (1809) he became professor of chemistry. From 1808 to 1832, he was professor of physics at the Sorbonne, a post which he only resigned for the chair of chemistry at the Jardin des Plantes. In 1821, he was elected a foreign member of the Royal Swedish Academy of Sciences.

William Gilbert

(24 May 1544 – 30 November 1603)

William Gilbert was an English physician, physicist and natural philosopher who is credited as one of the originators of the term electricity. A unit of magnetomotive force was named the gilbert in his honour.

Gilbert concluded that the Earth was itself magnetic and that this was the reason compasses point north, and was also the first person to state that the centre of the Earth was iron. Twenty years before Galileo he pointed out the motion of the skies was due to Earth's rotation. He also made the first attempt to map the surface markings on the Moon in the 1590s.

Joseph Henry

(17 December 1797 – 13 May 1878)

Joseph Henry was an American scientist who discovered the electromagnetic phenomenon of self-inductance. He also discovered mutual inductance independently of Michael Faraday, though Faraday was the first to publish his results. The SI unit of inductance, the henry, is named in his honour.

Heinrich Rudolf Hertz

(22 February 1857 – 1 January 1894)

Heinrich Rudolf Hertz was the first person to conclusively prove the existence of electromagnetic waves. The scientific unit of frequency was named the hertz in his honour.

In some of his more advanced experiments, Hertz measured the velocity of electromagnetic radiation and found it to be the same as light’s velocity. He also established beyond any doubt that light is a form of electromagnetic radiation.

His experiments expanded the field of electromagnetic transmission, and he also found that radio waves could be transmitted through different types of materials but were reflected by others, leading in the distant future to radar.

His discoveries would later be more fully understood by others and be part of the new ‘wireless age’.

Robert Hooke

(28 July 1635 – 3 March 1703)

Robert Hooke was an English natural philosopher, architect and polymath.

Robert Hooke was born in 1635 in Freshwater on the Isle of Wight. On his father's death in 1648, Robert was left forty pounds, a sum that enabled him to buy an apprenticeship. Hooke studied at Wadham College during the Protectorate where he became one of a tightly knit group of ardent Royalists centred around John Wilkins. Here he was employed as an assistant to Thomas Willis and to Robert Boyle, for whom he built the vacuum pumps used in Boyle's gas law experiments. He built some of the earliest Gregorian telescopes, observed the rotations of Mars and Jupiter and, based on his observations of fossils, was an early advocate of biological evolution. He investigated the phenomenon of refraction, deducing the wave theory of light, and was the first to suggest that matter expands when heated and that air is made of small particles separated by relatively large distances. He performed pioneering work in the field of surveying and map-making and was involved in the work that led to the first modern plan-form map.

In 1660, Hooke discovered the law of elasticity which bears his name and which describes the linear variation of tension with extension in an elastic spring.

In 1665 Hooke published Micrographia, a book describing microscopic and telescopic observations, and some original work in biology. During this period Hooke coined the term cell for describing biological organisms.

Micrographia also contains Hooke's ideas on combustion. His experiments led him to conclude that combustion involves a substance that is mixed with air, a statement with which modern scientists would agree, but that was not widely understood at the time. Hooke went on to conclude that respiration also involves a specific component of the air.

James Prescott Joule

(24 December 1818 – 11 October 1889)

James Prescott Joule FRS was an English physicist and brewer. He studied the nature of heat, and discovered its relationship to mechanical work. This led to the theory of conservation of energy, which in turn led to the development of the first law of thermodynamics. The SI derived unit of energy, the joule, is named after him.

William Thomson, 1st Baron Kelvin

(26 June 1824 – 17 December 1907)

William Thomson, 1st Baron Kelvin, OM, GCVO, PC, PRS, PRSE, was an Irish mathematical physicist and engineer who was born in Belfast.

At the University of Glasgow he did important work in the mathematical analysis of electricity and formulation of the first and second laws of thermodynamics, and did much to unify the emerging discipline of physics in its modern form. He also had a career as an electric telegraph engineer and inventor, which propelled him into the public eye and ensured his wealth, fame and honour. For his work on the transatlantic telegraph project he was knighted by Queen Victoria, becoming Sir William Thomson.

Lord Kelvin is widely known for determining the correct value of absolute zero as approximately - 273.15 Celsius. Absolute temperatures are stated in units of kelvin in his honour.

Gustav Robert Kirchhoff

(12 March 1824 – 17 October 1887)

Gustav Robert Kirchhoff was a German physicist.

Concepts in circuit theory and thermal emission are named ‘Kirchhoff’s laws’ after him, as well as a law of thermochemistry.

Kirchhoff formulated his circuit laws in 1845 while still a student. In 1857 he calculated that an electric signal in a resistance-free wire travels along the wire at the speed of light. He proposed his law of thermal radiation in 1859, and gave a proof in 1861.

Georges Leclanché

(1839 – September 14, 1882)

Georges Leclanché was a French electrical engineer who invented the Leclanché cell, one of the first modern electrical batteries and the forerunner of the modern dry cell battery. The Leclanché cell comprised of a conducting solution (electrolyte) of ammonium chloride with a negative terminal of zinc and a positive terminal of manganese dioxide.

Heinrich Friedrich Emil Lenz

(12 February 1804 – 10 February 1865)

Heinrich Friedrich Emil Lenz was a Russian physicist remembered for formulating Lenz's law in electrodynamics. The symbol L, conventionally representing inductance, is chosen in his honour. He also independently discovered Joules’ law in 1842.

James Clerk Maxwell

(13 June 1831 – 5 November 1879)

James Clerk Maxwell was a Scottish theoretical physicist who formulated classical electromagnetic theory. His equations demonstrate that electricity, magnetism and light are all manifestations of the same thing - the electromagnetic field.

Maxwell demonstrated that electric and magnetic fields travel through space in the form of waves and at the constant speed of light. He also helped develop the Maxwell–Boltzmann distribution, a means of describing aspects of the kinetic theory of gases and presenting the first durable colour photograph in 1861.

Sir Isaac Newton

25 December 1642 – 20 March 1727)

Sir Isaac Newton was the English polymath who laid the foundations for much of classical mechanics used today. He showed that the motions of objects are governed by the same set of natural laws by demonstrating the consistency between Kepler's laws of planetary motion and his own theory of gravitation.

Newton was appointed Lucasian Professor of Mathematics in 1669. From 1670 to 1672, Newton lectured on optics. During this period he investigated refraction, demonstrating that a prism could decompose white light into a spectrum of colours, and that a lens and a second prism could recompose the multicoloured spectrum into white light. He also showed that the coloured light does not change its properties by separating out a coloured beam and shining it on various objects. Newton observed that colour is the result of objects interacting with already-coloured light rather than objects generating the colour themselves. This is known as Newton's theory of colour.

From this work, he concluded that the lens of any refracting telescope would suffer from the dispersion of light into colours (chromatic aberration). As a proof of this he constructed the first known functional reflecting telescope, today known as a Newtonian telescope, which involved solving the problems of suitable mirror material and shaping.

The Principia was published on 5 July 1687. In this work, Newton stated the three universal laws of motion.

Newton's First Law (also known as the Law of Inertia) states that an object at rest tends to stay at rest and that an object in uniform motion tends to stay in uniform motion unless acted upon by a net external force.

Newton's Second Law states that an applied force on an object equals the rate of change of its momentum with time. The SI unit of force is the newton, named in Newton's honour.

Newton's Third Law states that for every action there is an equal and opposite reaction. This means that any force exerted onto an object has a counterpart force that is exerted in the opposite direction back onto the first object.

Blaise Pascal

(19 June 1623 – 19 August 1662)

Blaise Pascal was a French polymath. A child prodigy educated by his father, Pascal’s earliest work was in the natural and applied sciences, where he made important contributions to the study of fluids, and clarified the concepts of pressure and vacuum.

Pascal went on to become an important mathematician, helping create two major new areas of research: he wrote a significant treatise on the subject of projective geometry at the age of 16, and later corresponded with Pierre de Fermat on probability theory, strongly influencing the development of modern economics and social science.

Pythagoras of Samos

(born about bc 570 and died about bc 495)

Pythagoras of Samos was an Ionian Greek philosopher and mathematician. Pythagoras made influential contributions to philosophy in the late sixth century bc. He is best known for the Pythagorean theorem, which states that in a right-angled triangle the area of the square of the hypotenuse (the side opposite the right-angle) is equal to the sum of the areas of the squares of the other two sides – that is, a² + b² = c².

Nikola Tesla

(10 July 1856 – 7 January 1943)

Nikola Tesla started working in the telephony and electrical fields before emigrating to the United States in 1884 to work for Thomas Edison. He soon struck out on his own though, setting up laboratories and companies to develop a range of electrical devices. In 1960, in honour of Tesla, the term tesla was coined for the SI unit measure for magnetic field strength.

Alessandro Giuseppe Antonio Anastasio Volta

(18 February 1745 – 5 March 1827)

Alessandro Giuseppe Antonio Anastasio Volta was the Italian physicist that invented the battery.

Volta studied the chemistry of gases, discovering methane. Volta also studied electrical capacitance, developing means to study both electrical potential (V) and charge (Q), and discovering that for a given object, they are proportional. This was named Volta's Law of capacitance, and as a result of this work the unit of electrical potential is called the volt.

James Watt

(19 January 1736 – 25 August 1819)

James Wattwas a Scottish inventor and mechanical engineer.

While working at the University of Glasgow, Watt realised that the engine designs of the time wasted energy by repeatedly cooling then reheating the cylinder. He introduced a separate condenser, which radically improved both the power and efficiency of steam engines.

The watt is named after him – the unit of power incorporated in the International System of Units (or ‘SI’).

Wilhelm Eduard Weber

(24 October 1804 – 23 June 1891)

Wilhelm Eduard Weber was a German physicist who, together with Gauss, invented the first electromagnetic telegraph.

He studied magnetism with Gauss, and during 1864 published his Electrodynamic Proportional Measures, which contained a system of absolute measurements for electric currents and forms the basis of those in use today. The SI unit of magnetic flux, the weber (Wb) is named after him.

Sir Charles Wheatstone

(6 February 1802 – 19 October 1875)

Sir Charles Wheatstone was an English scientist and inventor of the concertina, the stereoscope, and the Playfair cipher. He is best known for his contributions in the development of the Wheatstone bridge, which is used to measure an unknown electrical resistance.

Thomas Young

(13 June 1773 – 10 May 1829)

Thomas Young was an English polymath. He is famous for having partly deciphered Egyptian hieroglyphics (specifically the Rosetta Stone). Young made notable scientific contributions to the fields of vision, light, solid mechanics, energy, physiology, language, musical harmony and Egyptology.

At the age of 14 Young had learned Greek and Latin and was acquainted with French, Italian, Hebrew, German, Chaldean, Syriac, Samaritan, Arabic, Persian, Turkish and Amharic. Young’s modulus relates the stress (pressure) in a body to its associated strain (change in length as a ratio of the original length). For the first time it allowed prediction of the strain in a component subject to a known stress (and vice versa). Young’s modulus depends only on the material, not its geometry, thus allowing a revolution in engineering strategies.

Young has also been called the founder of physiological optics. In 1793 he explained the mode in which the eye accommodates itself to vision at different distances as depending on changes of the curvature of the crystalline lens, being the first to describe astigmatism, and hypothesized that colour perception depends on the presence in the retina of three kinds of nerve fibres.