View source for List of Dutch discoveries

{{short description|None}}
{{Cleanup|reason=excessive [[WP:REFBLOAT]]|talksection=Cleanup proposal|date=May 2016}}
{{Use dmy dates|date=January 2022}}
{{History of the Netherlands}}

The following list is composed of objects, concepts, phenomena and processes that were discovered or invented by people from the [[Netherlands]].

{{TOC limit|3}}

== Discoveries ==
=== Archaeology ===

==== Java Man (Homo erectus erectus) (1891) ====
[[File:Pithecanthropus-erectus.jpg|thumb|Original fossils of ''Pithecanthropus erectus'' (now ''Homo erectus'') found in Java in 1891. Estimated to be between 700,000 and 1,000,000 years old, at the time of their discovery the fossils of "[[Java Man]]" were the oldest [[hominin]] fossils ever found.]]
[[Java Man]] (''Homo erectus erectus'') is the name given to hominid fossils discovered in 1891 at [[Trinil]] – [[Ngawi Regency]] on the banks of the Solo River in [[East Java]], [[Indonesia]], one of the first known specimens of [[Homo erectus]]. Its discoverer, Dutch paleontologist [[Eugène Dubois]], gave it the scientific name '''Pithecanthropus erectus''', a name derived from Greek and Latin roots meaning ''upright ape-man''.

=== Astronomy ===
==== Columba (constellation) (1592) ====

[[Constellation Columba|Columba]] is a small, faint [[constellation]] named in the late sixteenth century. Its name is [[Latin]] for [[dove]]. It is located just south of [[Canis Major]] and [[Lepus (constellation)|Lepus]]. Columba was named by Dutch astronomer [[Petrus Plancius]] in 1592 in order to differentiate the 'unformed stars' of the large constellation [[Canis Major]]. Plancius first depicted Columba on the small celestial planispheres of his large wall map of 1592. It is also shown on his smaller world map of 1594 and on early Dutch celestial globes.

==== Novaya Zemlya effect (1597) ====
The first person to record the [[Novaya Zemlya effect]] was [[Gerrit de Veer]], a member of [[Willem Barentsz]]' ill-fated third expedition into the polar region. [[Novaya Zemlya]], the [[archipelago]] where de Veer first observed the phenomenon, lends its name to the effect.

==== 12 southern constellations (1597–1598) ====
Plancius defined 12 constellations created by Plancius from the observations of [[Pieter Dirkszoon Keyser]] and [[Frederick de Houtman]].<ref name="Ridpath, Ian 1988 p. 9–10">Ridpath, Ian (1988). ''Star Tales'', p. 9–10</ref><ref name="Lankford, John 1997 p. 161">Lankford, John (1997). ''History of Astronomy: An Encyclopedia'', p. 161</ref><ref name="Stephenson, Bruce 2000 p. 24">Stephenson, Bruce; Bolt, Marvin; Friedman, Anna Felicity (2000). ''The Universe Unveiled: Instruments and Images Through History'', p. 24</ref><ref name="Kanas, Nick 2007 p. 119–21">Kanas, Nick (2007). ''Star Maps: History, Artistry, and Cartography'', p. 119–21</ref><ref name="Gendler, Robert 2011 p. 14">Gendler, Robert; Christensen, Lars Lindberg; Malin, David (2011). ''Treasures of the Southern Sky'', p. 14</ref><ref name="Simpson, Phil 2012 p. 559–61">Simpson, Phil (2012). ''Guidebook to the Constellations: Telescopic Sights, Tales, and Myths'', p. 559–61</ref><ref name="Ridpath, Ian 2012 p. 96">Ridpath, Ian (2012). ''A Dictionary of Astronomy (Oxford Paperback Reference)'', p. 96</ref>
* ''[[Apus]]'' is a faint constellation in the [[southern sky]], first defined in the late 16th century. Its name means "no feet" in Greek, and it represents a [[bird-of-paradise]] (once believed to lack feet). It first appeared on a 35&nbsp;cm diameter celestial globe published in 1597 (or 1598) in Amsterdam by Plancius with [[Jodocus Hondius]].
* ''[[Chamaeleon]]'' is named after the [[chameleon]], a kind of [[lizard]].
* ''[[Dorado]]'' is now one of the 88 modern constellations. Dorado has been represented historically as a [[dolphinfish]] and a [[swordfish]].
* ''[[Grus (constellation)|Grus]]'' is Latin for the [[crane (bird)|crane]], a species of bird. The stars that form Grus were originally considered part of [[Piscis Austrinus]] (the southern fish).
* ''[[Hydrus]]''' name means "male water snake".
* ''[[Indus (constellation)|Indus]]'' represents an Indian, a word that could refer at the time to any native of Asia or the Americas.
* ''[[Musca]]'' is one of the minor southern constellations. It first appeared on a 35-cm diameter celestial globe published in 1597 (or 1598) in Amsterdam by Plancius and Hondius. The first depiction of this constellation in a celestial atlas was in [[Johann Bayer]]'s ''[[Uranometria]]'' of 1603.
* ''[[Pavo (constellation)|Pavo]]'' is [[Latin]] for [[peacock]].
* ''[[Phoenix (constellation)|Phoenix]]'' is a minor southern constellation, named after the mythical [[phoenix (mythology)|phoenix]]. It was the largest of the twelve.
* ''[[Triangulum Australe]]'' is Latin for "the southern triangle", which distinguishes it from [[Triangulum]] in the northern sky and is derived from the almost equilateral pattern of its three brightest stars. It was first depicted on a [[celestial globe]] as Triangulus Antarcticus by Plancius in 1589, and later with more accuracy and its current name by [[Johann Bayer]] in his 1603 ''Uranometria''.
* ''[[Tucana]]'' is Latin for the [[toucan]], a South American bird.
* ''[[Volans]]'' represents a [[flying fish]]; its name is a shortened form of its original name, ''Piscis Volans''.

==== Camelopardalis (constellation) (1612–1613) ====
''Camelopardalis'' was created by Plancius in 1613 to represent the animal [[Rebecca]] rode to marry [[Isaac]] in [[the Bible]]. One year later, [[Jakob Bartsch]] featured it in his atlas. [[Johannes Hevelius]] gave it the official name of "Camelopardus" or "Camelopardalis" because he saw the [[constellation]]'s many faint stars as the spots of a [[giraffe]].

==== Monoceros (constellation) (1612–1613) ====
''Monoceros'' is a relatively modern creation. Its first certain appearance was on a globe created by Plancius in 1612 or 1613. It was later charted by Bartsch as ''Unicornus'' in his 1624 star chart.

==== Rings of Saturn (1655) ====
[[Image:Unraveling Saturn's Rings.jpg|right|thumb|200px|[[Christiaan Huygens]] was the first person to describe [[Rings of Saturn|Saturn's rings]] as a disk surrounding [[Saturn]]]]

In 1655, [[Christiaan Huygens|Huygens]] became the first person to suggest that Saturn was surrounded by a ring, after Galileo's much less advanced telescope had failed to show rings. Galileo had reported the anomaly as possibly 3 planets instead of one.

==== Titan (Saturn's moon) (1655) ====
[[Image:Titan in natural color Cassini.jpg|thumb|right|200px|[[Titan (moon)|Titan]] was the first known [[Moons of Saturn|moon of Saturn]], discovered in 1655 by [[Christiaan Huygens]].]]

In 1655, using a 50 power [[refracting telescope]] that he designed himself, Huygens discovered the first of [[Saturn]]'s moons, [[Titan (moon)|Titan]].

==== Kapteyn's Star (1897) ====
[[Kapteyn's Star]] is a [[Stellar classification|class M1]] [[red dwarf]] about 12.76 [[light-year]]s from Earth in the southern [[constellation]] [[Pictor]], and the closest [[galactic halo|halo]] star to the Solar System. With a [[apparent magnitude|magnitude]] of nearly 9 it is visible through [[binoculars]] or a [[telescope]]. It had the highest [[proper motion]] of any star known until the discovery of [[Barnard's Star]] in 1916. Attention was first drawn to what is now known as [[Kapteyn's Star]] by the Dutch astronomer [[Jacobus Kapteyn]], in 1897.

==== Discovery of evidence for galactic rotation (1904) ====
In 1904, studying the [[proper motion]]s of stars, Dutch astronomer [[Jacobus Kapteyn]] reported that these were not random, as it was believed in that time; stars could be divided into two streams, moving in nearly opposite directions. It was later realized that Kapteyn's data had been the first evidence of the rotation of our [[Galaxy]], which ultimately led to the finding of [[Galaxy rotation curve|galactic rotation]] by [[Bertil Lindblad]] and [[Jan Oort]].

==== Galactic halo (1924) ====
In 1924, Dutch astronomer [[Jan Oort]] [[:Category:Discoveries by Jan Oort|discovered]] the [[galactic halo]], a group of stars orbiting the [[Milky Way]] but outside the main disk.

==== Oort constants (1927) ====
The [[Oort constants]] (discovered by [[Jan Oort]]) <math>A</math> and <math>B</math> are empirically derived parameters that characterize the local rotational properties of the [[Milky Way]].

==== Evidence of dark matter (1932) ====
In 1932, Dutch astronomer [[Jan Oort]] became the first person to discover evidence of [[dark matter]]. Oort proposed the substance after measuring the motions of nearby stars in the [[Milky Way]] relative to the galactic plane. He found that the mass of the galactic plane must be more than the mass of the material that can be seen. A year later (1933), [[Fritz Zwicky]] examined the dynamics of clusters of galaxies and found their movements similarly perplexing.

==== Discovery of methane in the atmosphere of Titan (1944) ====
The first formal proof of the existence of an [[Atmosphere of Titan|atmosphere]] around [[Titan (moon)|Titan]] came in 1944, when [[Gerard Kuiper]] observed Titan with the new McDonald {{convert|82|in|m|adj=on}} telescope and discovered spectral signatures on Titan at wavelengths longer than 0.6&nbsp;μm (micrometers), among which he identified two absorption bands of [[methane]] at 6190 and 7250&nbsp;Å (Kuiper1944). This discovery was significant not only because it requires a dense [[atmosphere]] with a significant fraction of methane, but also because the atmosphere needs to be chemically evolved, since methane requires [[hydrogen]] in the presence of [[carbon]], and molecular and atomic hydrogen would have escaped from Titan's weak gravitational field since the formation of the [[Solar System]].<ref>Brown, Robert Hanbury; Lebreton, Jean-Pierre; Waite, John H. (2009). ''Titan from Cassini-Huygens'', p. 10</ref>

==== Discovery of carbon dioxide in the atmosphere of Mars (1947) ====
Using [[infrared]] spectrometry, in 1947 the Dutch-American astronomer [[Gerard Kuiper]] detected [[carbon dioxide]] in the [[Atmosphere of Mars|Martian atmosphere]], a discovery of biological significance because it is a principal [[gas]] in the process of [[photosynthesis]] (see also: [[History of Mars observation]]). He was able to estimate that the amount of carbon dioxide over a given area of the surface is double that on the [[Earth]].

==== Miranda (Uranus's moon) (1948) ====
[[Miranda (moon)|Miranda]] is the smallest and innermost of [[Uranus]]'s five major moons. It was discovered by [[Gerard Kuiper]] on 16 February 1948 at [[McDonald Observatory]].

==== Nereid (Neptune's moon) (1949) ====
[[Nereid (moon)|Nereid]], also known as Neptune II, is the third-largest [[natural satellite|moon]] of [[Neptune]] and was its second moon to be discovered, on 1 May 1949, by Gerard Kuiper, on photographic plates taken with the 82-inch telescope at McDonald Observatory.

==== Oort cloud (1950) ====
The ''[[Oort cloud]]'' or ''Öpik–Oort cloud'', named after Dutch astronomer [[Jan Oort]] and Estonian astronomer [[Ernst Öpik]], is a spherical cloud of predominantly [[Volatile (astrogeology)|icy]] [[planetesimal]]s believed to surround the [[Sun]] at a distance of up to {{convert|50000|AU|ly|abbr=on|lk=on|sigfig=1}}. Further evidence for the existence of the [[Kuiper belt]] emerged from the study of comets. That comets have finite lifespans has been known for some time. As they approach the Sun, its heat causes their [[volatility (physics)|volatile]] surfaces to sublimate into space, gradually evaporating them. In order for comets to continue to be visible over the age of the Solar System, they must be replenished frequently.<ref name="matter">{{cite journal | author=David Jewitt | title=From Kuiper Belt Object to Cometary Nucleus: The Missing Ultrared Matter | journal=[[The Astronomical Journal]] | volume=123 | issue=2 | pages=1039–49 | year=2002 | doi=10.1086/338692 | bibcode=2002AJ....123.1039J| s2cid=122240711 | doi-access=free }}</ref> One such area of replenishment is the [[Oort cloud]], a spherical swarm of comets extending beyond 50,000 [[Astronomical unit|AU]] from the Sun first hypothesised by Dutch astronomer [[:Category:Discoveries by Jan Oort|Jan Oort]] in 1950.<ref>{{cite journal |bibcode=1950BAN....11...91O |title=The structure of the cloud of comets surrounding the Solar System and a hypothesis concerning its origin |last1=Oort |first1=J. H. |volume=11 |year=1950 |page=91 |journal=Bull. Astron. Inst. Neth.}}</ref> The [[Oort cloud]] is believed to be the point of origin of [[long-period comet]]s, which are those, like [[Comet Hale–Bopp|Hale–Bopp]], with orbits lasting thousands of years.

==== Kuiper belt (1951) ====
The [[Kuiper belt]] was named after Dutch-American astronomer [[Gerard Kuiper]], regarded by many as the father of modern [[planetary science]], though his role in hypothesising it has been heavily contested. In 1951, he proposed the existence of what is now called the [[Kuiper Belt]], a disk-shaped region of [[minor planets]] outside the orbit of [[Neptune]], which also is a source of short-period [[comet]]s.

=== Biology ===
==== Function of the fallopian tubes (1660s) ====
Dutch physician and anatomist [[Regnier de Graaf]] may have been the first to understand the reproductive function of the [[fallopian tube]]s. He described the [[hydrosalpinx]], linking its development to female [[infertility]]. de Graaf recognized pathologic conditions of the tubes. He was aware of tubal pregnancies, and he surmised that the mammalian egg traveled from the [[ovary]] to the [[uterus]] through the tube.

==== Development of ovarian follicles (1672) ====
In his ''De Mulierum Organis Generatione Inservientibus'' (1672), de Graaf provided the first thorough description of the female [[gonad]] and established that it produced the [[ovum]]. De Graaf used the terminology [[vesicle (biology and chemistry)|vesicle]] or egg (ovum) for what now called the [[ovarian follicle]]. Because the fluid-filled ovarian vesicles had been observed previously by others, including [[Andreas Vesalius]] and [[Falloppio]], De Graaf did not claim their discovery. He noted that he was not the first to describe them, but to describe their development. De Graaf was the first to observe changes in the ovary before and after mating and describe the [[corpus luteum]]. From the observation of [[pregnancy]] in rabbits, he concluded that the follicle contained the [[oocyte]]. The mature stage of the ovarian follicle is called the [[Graafian follicle]] in his honour, although others, including [[Fallopius]], had noticed it previously but failed to recognize its reproductive significance.

==== Foundations of microbiology (discovery of microorganisms) (1670s) ====
[[Antonie van Leeuwenhoek]] is often considered to be the [[List of people considered father or mother of a scientific field|father]] of [[microbiology]]. [[Robert Hooke]] is cited as the first to record microscopic observation of the fruiting bodies of [[Mold (fungus)|mold]]s, in 1665. However, the first observation of [[microbe]]s using a microscope is generally credited to van Leeuwenhoek. In the 1670s, he observed and researched bacteria and other [[microorganism]]s, using a single-lens microscope of his own design.<ref name="Windelspecht, Michael 2002 p. 168">Windelspecht, Michael (2002). ''Groundbreaking Scientific Experiments, Inventions, and Discoveries of the 17th Century (Groundbreaking Scientific Experiments, Inventions and Discoveries through the Ages)'', p. 168</ref><ref>Fensham, Peter J.; Gunstone, Richard F.; White, Richard Thomas (1994). ''The Content of Science: A Constructivist Approach to Its Teaching and Learning'', p. 164–65</ref><ref>Aneja, K. R. (2003). ''Experiments in Microbiology, Plant Pathology and Biotechnology'', p. 8</ref><ref>Huerta, Robert D. (2003). ''Giants of Delft: Johannes Vermeer and the Natural Philosophers. The Parallel Search for Knowledge During the Age of Discovery'', p. 30</ref><ref>Cullen, Katherine E. (2006). ''Biology: The People Behind the Science'', p. 24</ref><ref>Ghoshal, Sabari (2009). ''Fundamentals of Bioanalytical Techniques and Instrumentation'', p. 19</ref><ref>Wayne, Randy O. (2009). ''Plant Cell Biology: From Astronomy to Zoology'', p. 299</ref><ref name="Maczulak, Anne 2010 p. 1–2">Maczulak, Anne (2010). ''Allies and Enemies: How the World Depends on Bacteria'', p. 12</ref><ref>Huff, Toby E. (2010). ''Intellectual Curiosity and the Scientific Revolution: A Global Perspective'', p. 198–205</ref><ref>Arp, Robert (2013). ''1001 Ideas That Changed the Way We Think'', p. 374</ref><ref>{{cite web|url=http://www.timeshighereducation.co.uk/418426.article |author=Grove, Jack |title=Striving to be first among equals |publisher=Times Higher Education |date=15 December 2011 |accessdate=18 May 2014 }}</ref>

In 1981 the British microscopist [[Brian J. Ford]] found that Leeuwenhoek's original specimens had survived in the collections of the Royal Society of London.<ref>{{cite web|url=http://www.brianjford.com/wavintr.htm |title=The discovery by Brian J Ford of Leeuwenhoek's original specimens, from the dawn of microscopy in the 16th century |publisher=Brianjford.com |accessdate=2010-06-13}}</ref> They were found to be of high quality, and were all well preserved. Ford carried out observations with a range of microscopes, adding to our knowledge of Leeuwenhoek's work.<ref>Huerta, Robert D. (2003). ''Giants of Delft: Johannes Vermeer and the Natural Philosophers: the Parallel Search for Knowledge During the Age of Discovery'', p. 32</ref>

==== Photosynthesis (1779) ====
[[Photosynthesis]] is a fundamental [[biochemistry|biochemical]] process in which plants, [[alga]]e, and some [[bacterium|bacteria]] convert sunlight to chemical energy. The process was discovered by [[Jan Ingenhousz]] in 1779.<ref>Ord, M.G.; Stocken, L.A. (1997). ''Further Milestones in Biochemistry (Foundations of Modern Biochemistry)'', p. 25</ref><ref>Blankenship, Robert E. (2002). ''Molecular Mechanisms of Photosynthesis'', p. 28</ref><ref>McDonald, Maurice S. (2003). ''Photobiology of Higher Plants'', p. 34</ref><ref>Rezende, Lisa (2006). ''Chronology of Science'', p. 151</ref><ref>Stiles, Walter (2006). ''Principles of Plant Physiology'', p. 162</ref><ref>Haven, Kendall (2007). ''100 Greatest Science Discoveries of All Time'', p. 45</ref><ref>Möller, Detlev (2010). ''Chemistry of the Climate System'', p. 83–84</ref><ref>Magiels, Geerdt (2010). ''From Sunlight to Insight: Jan IngenHousz, the Discovery of Photosynthesis & Science in the Light of Ecology'', p. 7</ref><ref>Rogers, Kara (2011). ''The Chemical Reactions of Life: From Metabolism to Photosynthesis'', p. 182–84</ref><ref>Ihde, Aaron John (2012). ''The Development of Modern Chemistry'', p. 419</ref><ref>Hill, Jane F. (2013). ''Chemical Research on Plant Growth: A translation of Théodore de Saussure's Recherches chimiques sur la Végétation''</ref> The chemical energy is used to drive reactions such as the formation of sugars or the fixation of nitrogen into [[amino acid]]s, the building blocks for [[protein synthesis]]. Ultimately, nearly all living things depend on energy produced from photosynthesis. It is also responsible for producing the [[oxygen]] that makes animal life possible. Organisms that produce energy through photosynthesis are called [[photoautotroph]]s. Plants are the most visible representatives of photoautotrophs, but bacteria and algae also employ the process.

==== Plant respiration (1779) ====
Plant respiration was also discovered by Ingenhousz in 1779.

==== Foundations of virology (1898) ====
[[Martinus Beijerinck]] is considered one of the founders of [[History of virology|virology]]. In 1898, he published results on his filtration experiments, demonstrating that [[tobacco mosaic disease]] is caused by an infectious agent smaller than a bacterium. His results were in accordance with similar observations made by [[Dmitri Ivanovsky]] in 1892. Like Ivanovsky and [[Adolf Mayer]], predecessor at [[Wageningen]], Beijerinck could not culture the filterable infectious agent. He concluded that the agent can replicate and multiply in living plants. He named the new [[pathogen]] ''[[virus]]'' to indicate its non-bacterial nature. This discovery is considered to be the beginning of [[virology]].

==== Chemistry of photosynthesis (1931) ====
In 1931, [[C. B. van Niel|Cornelis van Niel]] made key discoveries explaining the [[chemistry]] of [[photosynthesis]]. By studying [[purple sulfur bacteria]] and [[green sulfur bacteria]], he was the first scientist to demonstrate that photosynthesis is a [[Light-dependent reaction|light-dependent]] [[redox]] reaction, in which [[hydrogen]] reduces [[carbon dioxide]].<ref>Stenesh, J. (1998). ''Biochemistry'', p. 377</ref><ref>Khanna, Pragya (2008). ''Cell and Molecular Biology'', p. 151</ref> Expressed as:
:2 H<sub>2</sub>A + CO<sub>2</sub> → 2A + CH<sub>2</sub>O + H<sub>2</sub>O

where A is the [[electron acceptor]]. His discovery predicted that H<sub>2</sub>O is the hydrogen donor in green plant photosynthesis and is oxidized to O<sub>2</sub>. The chemical summation of photosynthesis was a milestone in the understanding of the chemistry of photosynthesis. This was later experimentally verified by [[Robin Hill (biochemist)|Robert Hill]].

==== Foundations of modern ethology (Tinbergen's four questions) (1930s) ====
Many [[naturalists]] have studied aspects of animal behaviour throughout history. [[Ethology]] has its scientific roots in the work of Charles Darwin and of American and German ornithologists of the late 19th and early 20th century, including Charles O. Whitman, Oskar Heinroth, and Wallace Craig. The modern discipline of [[ethology]] is generally considered to have begun during the 1930s with the work of Dutch biologist [[Nikolaas Tinbergen]] and by Austrian biologists [[Konrad Lorenz]] and [[Karl von Frisch]].<ref>Burkhardt, Jr., Richard W. (2005). ''Patterns of Behavior: Konrad Lorenz, Niko Tinbergen, and the Founding of Ethology''. (University of Chicago Press)</ref>

[[Tinbergen's four questions]], named after [[Nikolaas Tinbergen]], one of the founders of modern [[ethology]], are complementary categories of explanations for behaviour. It suggests that an integrative understanding of behaviour must include both a proximate and ultimate (functional) analysis of behaviour, as well as an understanding of both phylogenetic/developmental history and the operation of current mechanisms.<ref>Daly, M & Wilson, M. (1983). Sex, evolution, and behaviour. Brooks-Cole.</ref>

==== Vroman effect (1975) ====
The [[Vroman effect]], named after [[Leo Vroman]], is exhibited by [[protein]] [[adsorption]] to a surface by [[blood plasma|blood serum]] proteins.

=== Chemistry ===
==== Concept of gas (1600s) ====

Flemish physician [[Jan Baptist van Helmont]] is sometimes considered the founder of [[pneumatic chemistry]], coining the word ''[[gas]]'' and conducting experiments involving gases. Van Helmont had derived the word "gas" from the Dutch word ''geest'', which means ghost or spirit.

==== Foundations of stereochemistry (1874) ====
Dutch chemist [[Jacobus Henricus van 't Hoff]] is generally considered to be one of the founders of the field of [[stereochemistry]]. In 1874, [[Jacobus Henricus van 't Hoff|Van 't Hoff]] built on the work on isomers of German chemist [[Johannes Wislicenus]], and showed that the four valencies of the [[carbon atom]] were probably directed in space toward the four corners of a regular tetrahedron, a model which explained how optical activity could be associated with an asymmetric carbon atom. He shares credit for this with the French chemist [[Joseph Le Bel]], who independently came up with the same idea. Three months before his doctoral degree was awarded Van 't Hoff published this theory, which today is regarded as the foundation of [[stereochemistry]], first in a Dutch pamphlet in the fall of 1874, and then in the following May in a small French book entitled ''La chimie dans l'espace''. A German translation appeared in 1877, at a time when the only job Van 't Hoff could find was at the Veterinary School in [[Utrecht]]. In these early years his theory was largely ignored by the scientific community, and was sharply criticized by one prominent chemist, [[Hermann Kolbe]]. However, by about 1880 support for Van 't Hoff's theory by such important chemists as [[Johannes Wislicenus]] and [[Viktor Meyer]] brought recognition.

==== Foundations of modern physical chemistry (1880s) ====
[[Jacobus van 't Hoff]] is also considered as one of the modern founders of the disciple of [[physical chemistry]].<ref>[[Keith J. Laidler|Laidler, Keith J.]] ''Chemical Kinetics and the Origins of Physical Chemistry''. (''Archive for History of Exact Sciences'', March 1985, Volume 32, Issue 1, p. 43–75)</ref> The first scientific journal specifically in the field of physical chemistry was the German journal, ''Zeitschrift für Physikalische Chemie'', founded in 1887 by [[Wilhelm Ostwald]] and Van 't Hoff. Together with [[Svante Arrhenius]], these were the leading figures in physical chemistry in the late 19th century and early 20th century.

==== Van 't Hoff equation (1884) ====
The [[Van 't Hoff equation]] in [[chemical thermodynamics]] relates the change in the [[equilibrium constant]], ''K<sub>eq</sub>'', of a chemical equilibrium to the change in [[temperature]], ''T'', given the [[Enthalpy of formation|standard enthalpy change]], ''ΔH<sup><s>o</s></sup>'', for the process. It was proposed by Dutch chemist [[Jacobus Henricus van 't Hoff]] in 1884.<ref>[http://nobelprize.org/nobel_prizes/chemistry/laureates/1901/hoff-bio.html Biography on Nobel prize website]. Nobelprize.org (1 March 1911). Retrieved on 2013-11-8.</ref> The ''Van 't Hoff equation'' has been widely utilized to explore the changes in [[state functions]] in a [[thermodynamic system]]. The ''Van 't Hoff plot'', which is derived from this equation, is especially effective in estimating the change in [[enthalpy]], or total energy, and [[entropy]], or amount of disorder, of a [[chemical reaction]].

==== Van 't Hoff factor (1884) ====
The '''van 't Hoff factor <math> i </math>''' is a measure of the effect of a solute upon [[colligative properties]] such as [[osmotic pressure]], relative lowering in [[vapor pressure]], [[Boiling-point elevation|elevation of boiling point]] and [[freezing point depression]]. The [[van 't Hoff factor]] is the ratio between the actual concentration of particles produced when the substance is dissolved, and the [[concentration]] of a substance as calculated from its mass.

==== Lobry de Bruyn–van Ekenstein transformation (1885) ====
In [[carbohydrate chemistry]], the [[Lobry de Bruyn–van Ekenstein transformation]] is the base or acid-catalyzed transformation of an [[aldose]] into the [[ketose isomer]] or vice versa, with a tautomeric [[enediol]] as reaction intermediate. The transformation is relevant for the industrial production of certain [[ketose]]s and was discovered in 1885 by [[Cornelis Adriaan Lobry van Troostenburg de Bruyn]] and [[Willem Alberda van Ekenstein]].

==== Prins reaction (1919) ====
The Prins reaction is an [[organic reaction]] consisting of an [[electrophilic addition]] of an [[aldehyde]] or [[ketone]] to an [[alkene]] or [[alkyne]] followed by capture of a [[nucleophile]]. Dutch chemist Hendrik Jacobus Prins discovered two new [[organic reaction]]s, both now carrying the name [[Prins reaction]]. The first was the addition of [[polyhalogen]] compounds to [[olefin]]s, was found during Prins doctoral research, while the others, the acid-catalyzed addition of aldehydes to olefinic compounds, became of industrial relevance.

==== Hafnium (1923) ====
Dutch physicist [[Dirk Coster]] and Hungarian-Swedish chemist [[George de Hevesy]] co-discovered ''[[Hafnium]]'' (Hf) in 1923, by means of [[X-ray]] spectroscopic analysis of [[zirconium]] ore. ''Hafnium' is named after ''Hafnia', the Latin name for [[Copenhagen]] (Denmark), where it was discovered.

==== Crystal bar process (1925) ====
The [[crystal bar process]] (also known as ''iodide process'' or the ''van Arkel–de Boer process'') was developed by Dutch chemists [[Anton Eduard van Arkel]] and [[Jan Hendrik de Boer]] in 1925. It was the first industrial process for the commercial production of pure ductile metallic [[zirconium]]. It is used in the production of small quantities of ultra-pure [[titanium]] and zirconium.

==== Koopmans' theorem (1934) ====
[[Koopmans' theorem]] states that in closed-shell [[Hartree–Fock theory]], the first [[ionization energy]] of a molecular system is equal to the negative of the orbital energy of the highest occupied molecular orbital ([[HOMO]]). This theorem is named after [[Tjalling Koopmans]], who published this result in 1934.<ref>{{cite journal
 | last = Koopmans
 | first = Tjalling
 | title = Über die Zuordnung von Wellenfunktionen und Eigenwerten zu den einzelnen Elektronen eines Atoms
 | journal = Physica
 | year = 1934
 | volume = 1
 | issue = 1–6
 | pages = 104–13
 | publisher = Elsevier
 | doi = 10.1016/S0031-8914(34)90011-2
| bibcode=1934Phy.....1..104K}}
</ref>
Koopmans became a [[Nobel laureate]] in 1975, though neither in physics nor chemistry, but in [[Nobel Memorial Prize in Economic Sciences|economics]].

=== Genetics ===
==== Concept of pangene/gene (1889) ====

In 1889, Dutch botanist [[Hugo de Vries]] published his book ''Intracellular Pangenesis'', in which he postulated that different characters have different hereditary carriers, based on a modified version of [[Charles Darwin]]'s theory of [[Pangenesis]] of 1868. He specifically postulated that inheritance of specific traits in organisms comes in ''particles''. He called these units ''pangenes''.

==== Rediscovery the laws of inheritance (1900) ====
1900 marked the "rediscovery of [[Mendelian genetics]]". The significance of [[Gregor Mendel]]'s work was not understood until early in the twentieth century, after his death, when his research was re-discovered by [[Hugo de Vries]], [[Carl Correns]] and [[Erich von Tschermak]], who were working on similar problems.<ref>Kuiper, Kathleen (2010). ''The Britannica Guide to Theories and Ideas That Changed the Modern World'', p. 56</ref> They were unaware of Mendel's work. They worked independently on different plant hybrids, and came to Mendel's conclusions about the rules of [[inheritance]].

=== Geology ===
==== Bushveld Igneous Complex (1897) ====

The [[Bushveld Igneous Complex]] (or BIC) is a large, layered igneous intrusion within the Earth's crust that has been tilted and eroded and now outcrops around what appears to be the edge of a great geological basin, the [[Transvaal Basin]]. Located in South Africa, the BIC contains some of Earth's richest [[ore deposit]]s. The complex contains the world's largest reserves of [[platinum group metals]] (PGMs), [[platinum]], [[palladium]], [[osmium]], [[iridium]], [[rhodium]], and [[ruthenium]], along with vast quantities of iron, [[tin]], [[chromium]], [[titanium]] and [[vanadium]]. The site was discovered around 1897 by Dutch geologist [[Gustaaf Molengraaff]].

=== Mathematics ===
==== Differential geometry of curves (concepts of the involute and evolute of a curve) (1673) ====
[[Christiaan Huygens]] was the first to publish in 1673 (''[[Horologium Oscillatorium]]'') a specific method of determining the [[evolute]] and [[involute]] of a [[curve]]<ref>Ungs, Michael (2010). ''The Theory of Quantum Torus Knots: Its Foundation in Differential Geometry'', Volume II, p. 334</ref>

==== Korteweg–de Vries equation (1895) ====
In [[mathematics]], the [[Korteweg–de Vries equation]] ('''KdV equation''' for short) is a [[mathematical model]] of waves on shallow water surfaces. It is particularly notable as the prototypical example of an [[exactly solvable model]], that is, a non-linear [[partial differential equation]] whose solutions can be exactly and precisely specified. The equation is named for [[Diederik Korteweg]] and [[Gustav de Vries]] who, in 1895, proposed a mathematical model which allowed to predict the waves behaviour on shallow water surfaces.<ref>De Gloria, Alessandro (2014). ''Applications in Electronics Pervading Industry, Environment and Society'', p. 91</ref>

==== Proof of the Brouwer fixed-point theorem (1911) ====
[[Brouwer fixed-point theorem]] is a [[fixed-point theorem]] in [[topology]], named after Dutchman [[L. E. J. Brouwer|Luitzen Brouwer]], who proved it in 1911.

==== Proof of the hairy ball theorem (1912) ====
The [[hairy ball theorem]] of [[algebraic topology]] states that there is no nonvanishing [[continuous function|continuous]] tangent [[vector field]] on even-dimensional [[n‑sphere|''n''-spheres]]. The theorem was first stated by [[Henri Poincaré]] in the late 19th century. It was first proved in 1912 by [[Luitzen Egbertus Jan Brouwer|Brouwer]].<ref>[http://dz-srv1.sub.uni-goettingen.de/sub/digbib/loader?ht=VIEW&did=D28661 Georg-August-Universität Göttingen] {{webarchive|url=https://web.archive.org/web/20060526145611/http://dz-srv1.sub.uni-goettingen.de/sub/digbib/loader?ht=VIEW&did=D28661 |date=26 May 2006 }}</ref>

==== Debye functions (1912) ====
The [[Debye functions]] are named in honor of [[Peter Debye]], who came across this function (with ''n'' = 3) in 1912 when he analytically computed the [[heat capacity]] of what is now called the [[Debye model]].

==== Kramers–Kronig relations (1927) ====
The [[Kramers–Kronig relations]] are bidirectional [[mathematics|mathematical]] relations, connecting the [[real number|real]] and [[imaginary number|imaginary]] parts of any [[complex analysis|complex function]] that is [[analytic function|analytic]] in the [[upper half-plane]]. The relation is named in honor of [[Ralph Kronig]]<ref>{{cite journal|doi=10.1364/JOSA.12.000547|author=R. de L. Kronig| title=On the theory of the dispersion of X-rays|journal= J. Opt. Soc. Am.| volume=12|issue=6|pages= 547–57|year=1926}}</ref> and [[Hendrik Anthony Kramers]].<ref>{{cite journal| author=H.A. Kramers| title=La diffusion de la lumiere par les atomes| journal = Atti Cong. Intern. Fisici, (Transactions of Volta Centenary Congress) Como| volume = 2|pages=545–57 |year=1927}}</ref>

==== Heyting algebra (formalized intuitionistic logic) (1930) ====
Formalized [[intuitionistic logic]] was originally developed by [[Arend Heyting]] to provide a formal basis for [[Luitzen Brouwer]]'s programme of [[intuitionism]]. Arend Heyting introduced [[Heyting algebra]] (1930) to formalize [[intuitionistic logic]].<ref>Hesseling, Dennis E. (2003). ''Gnomes in the Fog: The Reception of Brouwer's Intuitionism in the 1920s''. (Birkhäuser Verlag)</ref><ref>Van Atten, Mark; Boldini, Pascal; Bourdeau, Michel; Heinzmann, Gerhard (2008). ''One Hundred Years of Intuitionism (1907–2007)''. (Birkhäuser Verlag)</ref>

==== Zernike polynomials (1934) ====
In mathematics, the [[Zernike polynomials]] are a [[polynomial sequence|sequence]] of [[polynomial]]s that are [[orthogonal polynomials|orthogonal]] on the [[unit disk]]. Named after [[Frits Zernike]], the Dutch optical physicist, and the inventor of [[phase contrast microscopy]], they play an important role in beam [[optics]].

==== Minnaert function (1941) ====
In 1941, [[Marcel Minnaert]] invented the [[Minnaert function]], which is used in optical measurements of celestial bodies. The [[Marcel Minnaert|Minnaert]] function is a [[photometry (astronomy)|photometric]] function used to interpret [[astronomical]] observations<ref>{{cite journal | doi = 10.1016/S0019-1035(03)00075-7 | bibcode=2003Icar..163..150C | volume=163 | issue=1 | title=Probing Titan's lower atmosphere with acousto-optic tuning | journal=Icarus | pages=150–63| year=2003 | last1=Chanover | first1=N.J. | last2=Anderson | first2=C.M. | last3=McKay | first3=C.P. | last4=Rannou | first4=P. | last5=Glenar | first5=D.A. | last6=Hillman | first6=J.J. | last7=Blass | first7=W.E. }}</ref><ref>{{cite journal | doi = 10.1016/j.icarus.2006.05.006 | bibcode=2006Icar..184..401S | volume=184 | issue=2 | title=Martian phase function: Modeling the visible to near-infrared surface photometric function using HST-WFPC2 data | journal=Icarus | pages=401–23| year=2006 | last1=Soderblom | first1=J. | last2=Belliii | first2=J. | last3=Hubbard | first3=M. | last4=Wolff | first4=M. }}</ref> and [[remote sensing]] data for the [[Earth]].<ref>{{cite journal | doi = 10.1080/01431160500104194 | volume=26 | issue=17 | title=The use of the Minnaert correction for land-cover classification in mountainous terrain | journal=International Journal of Remote Sensing | pages=3831–51| year=2005 | last1=Blesius | first1=L. | last2=Weirich | first2=F. | bibcode=2005IJRS...26.3831B | s2cid=129750287 }}</ref>

=== Mechanics ===
==== Proof of the law of equilibrium on an inclined plane (1586) ====

In 1586, [[Simon Stevin]] (Stevinus) derived the mechanical advantage of the [[inclined plane]] by an argument that used a string of beads.<ref name="Koetsier">{{cite conference
 | first = Teun
 | last = Koetsier
 | title = Simon Stevin and the rise of Archimedean mechanics in the Renaissance
 | book-title = The Genius of Archimedes – 23 Centuries of Influence on Mathematics, Science and Engineering: Proceedings of an International Conference Held at Syracuse, Italy, June 8–10, 2010
 | pages = 94–99
 | publisher = Springer
 | year = 2010
 | url = https://books.google.com/books?id=65Pz4_XJrgwC&pg=PA95
 | isbn = 978-90-481-9090-4
 }}</ref> Stevin's proof of the [[Inclined plane#History|law of equilibrium on an inclined plane]], known as the "Epitaph of Stevinus".

==== Centripetal force (1659) ====
[[Image:Centripetal force diagram.svg|thumb|A body experiencing [[uniform circular motion]] requires a [[centripetal force]], towards the axis as shown, to maintain its circular path. In 1659, [[Christiaan Huygens]] coined the term "[[centrifugal force]]" and was the first to derive the now standard mathematical description for the [[centripetal force]].]]
[[Christiaan Huygens]] stated what is now known as the second of Newton's laws of motion in a quadratic form.<ref name="mach">[[Ernst Mach]], ''The Science of Mechanics'' (1919), e.g. p. 143, p. 172 and p. 187 <https://archive.org/details/scienceofmechani005860mbp>.</ref> In 1659 he derived the now standard formula for the [[centripetal force]], exerted by an object describing a [[circular motion]], for instance on the string to which it is attached.<ref>Westfall, Richard S. (1971). ''The Construction of Modern Science: Mechanisms and Mechanics'', p. 130</ref><ref>Gindikin, Semyon Grigorevich (1988). ''Tales of Physicists and Mathematicians'', p. 86–87</ref><ref>Jammer, Max (1997). ''Concepts of Mass in Classical and Modern Physics'', p. 62–63</ref><ref>Jammer, Max (1999). ''Concepts of Force: A Study in the Foundations of Dynamics'', p. 109–10</ref><ref>Graneau, Peter; Graneau Neal (2006). ''In the Grip of the Distant Universe: The Science of Inertia'', p. 111–12</ref><ref>Ginzburg, Vladimir B.; Ginzburg, Tatyana V. (2007). ''Prime Elements of Ordinary Matter, Dark Matter & Dark Energy: Beyond Standard Model & String Theory'', p. 82–83</ref><ref>{{cite web|url=http://paginas.fe.up.pt/~feliz/e_paper30_in-defense-of-centrifugal-force-revised.pdf |author=Feliz-Teixeira, J. Manuel |title=In Defence of the Centrifugal Force and the Geometric Law of Motion |date= June 2011 |accessdate=28 April 2014 }}</ref> In modern notation:

:<math>F_{c}=\frac{m\ v^2}{r}</math>

with ''m'' the [[mass (physics)|mass]] of the object, ''v'' the [[velocity]] and ''r'' the [[radius]]. The publication of the general formula for this force in 1673 was a significant step in studying orbits in astronomy. It enabled the transition from [[Kepler's third law]] of planetary motion, to the [[inverse square law]] of gravitation.<ref>{{cite book|author=J. B. Barbour|title=Absolute Or Relative Motion?: The discovery of dynamics|url=https://books.google.com/books?id=ekA9AAAAIAAJ&pg=PA542|accessdate=23 April 2013|year=1989|publisher=CUP Archive|isbn=978-0-521-32467-0|page=542}}</ref>

==== Centrifugal force (1659) ====
Huygens coined the term ''[[centrifugal force]]'' in his 1659 ''De Vi Centrifiga'' and wrote of it in his 1673 ''Horologium Oscillatorium'' on [[pendulum]]s.

==== Formula for the period of mathematical pendulum (1659) ====
In 1659, [[Christiaan Huygens]] was the first to derive the formula for the [[Frequency|period]] of an ideal mathematical [[pendulum]] (with massless rod or cord and length much longer than its swing),<ref>Barbour, Julian B. (1989). ''Absolute or Relative Motion?: Volume 1, The Discovery of Dynamics: A Study from a Machian Point of View of the Discovery and the Structure of Dynamical Theories'', p. 454</ref><ref>Matthews, Michael; Gauld, Colin F.; Stinner, Arthur (2006). ''The Pendulum: Scientific, Historical, Philosophical and Educational Perspectives'', p. 9–10</ref><ref>Ginzburg, Vladimir B.; Ginzburg, Tatyana V. (2007). ''Prime Elements of Ordinary Matter, Dark Matter & Dark Energy: Beyond Standard Model & String Theory'', p. 82</ref><ref>Snygg, John (2011). ''A New Approach to Differential Geometry using Clifford's Geometric Algebra'', p. 195–202</ref><ref>Kautz, Richard (2011). ''Chaos: The Science of Predictable Random Motion'', p. 69–70</ref><ref>Filippov, Aleksandr T. (2011). ''The Versatile Soliton'', p. 68–69</ref><ref>Simonyi, Károly (2012). ''A Cultural History of Physics'', p. 240–55</ref> in modern notation:

:<math>T = 2 \pi \sqrt{\frac{l}{g}}</math>

with ''T'' the period, ''l'' the length of the [[pendulum]] and ''g'' the [[gravitational acceleration]]. By his study of the oscillation period of compound pendulums Huygens made contributions to the development of the concept of [[moment of inertia]].

==== Tautochrone curve (isochrone curve) (1659) ====
A [[tautochrone]] or [[isochrone curve]] is the curve for which the time taken by an object sliding without friction in uniform gravity to its lowest point is independent of its starting point. The curve is a [[cycloid]], and the time is equal to π times the square root of the radius over the [[Gravity of Earth|acceleration of gravity]]. [[Christiaan Huygens]] was the first to discover the [[tautochrone|tautochronous property]] (or [[isochrone curve|isochronous property]]) of the cycloid.<ref>Knoebel, Arthur; Laubenbacher, Reinhard; Lodder, Jerry; Pengelley, David (2007). ''Mathematical Masterpieces: Further Chronicles by the Explorers''. (Springer), p. 169.</ref> The [[tautochrone]] problem, the attempt to identify this curve, was solved by Christiaan Huygens in 1659. He proved geometrically in his ''[[Horologium Oscillatorium]]'', originally published in 1673, that the curve was a [[cycloid]]. Huygens also proved that the time of descent is equal to the time a body takes to fall vertically the same distance as the diameter of the circle which generates the cycloid, multiplied by π⁄2. The [[tautochrone curve]] is the same as the [[brachistochrone curve]] for any given starting point. [[Johann Bernoulli]] posed the problem of the [[brachistochrone]] to the readers of ''[[Acta Eruditorum]]'' in June, 1696. He published his solution in the journal in May of the following year, and noted that the solution is the same curve as Huygens's [[tautochrone curve]].<ref>Struik, Dirk Jan (1986). ''A Source Book in Mathematics, 1200–1800''. (Princeton University Press), p. 392</ref><ref>Farouki, Rida T. (2007). ''Pythagorean-Hodograph Curves: Algebra and Geometry Inseparable''. (Springer), p. 161.</ref>

==== Coupled oscillation (spontaneous synchronization) (1665) ====
[[Christiaan Huygens]] observed that two pendulum clocks mounted next to each other on the same support often become synchronized, swinging in opposite directions. In 1665, he reported the results by letter to the [[Royal Society of London]]. It is referred to as "an odd kind of sympathy" in the Society's minutes. This may be the first published observation of what is now called ''coupled oscillations''. In the 20th century, ''coupled oscillators'' took on great practical importance because of two discoveries: [[laser]]s, in which different atoms give off light waves that oscillate in unison, and [[superconductor]]s, in which pairs of electrons oscillate in synchrony, allowing electricity to flow with almost no resistance. ''Coupled oscillators'' are even more ubiquitous in nature, showing up, for example, in the synchronized flashing of fireflies and chirping of crickets, and in the pacemaker cells that regulate [[Cardiac cycle|heartbeats]].

=== Medicine ===
==== Foundations of modern (human) anatomy (1543) ====

[[Image:Vesalius 164frc.png|right|thumb|200px|One of the large, detailed illustrations in [[Andreas Vesalius]]'s ''[[De humani corporis fabrica]]'', 1543]]

Flemish anatomist and physician [[Andreas Vesalius]] is often referred to as the founder of modern [[human anatomy]] for the publication of the seven-volume ''[[De humani corporis fabrica]]'' (''On the Structure of the Human Body'') in 1543.

==== Crystals in gouty tophi (1679) ====
In 1679, van Leeuwenhoek used a microscopes to assess tophaceous material and found that [[Tophus|gouty tophi]] consist of aggregates of needle-shaped crystals, and not globules of chalk as was previously believed.

==== Boerhaave syndrome (1724) ====
[[Boerhaave syndrome]] (also known as ''spontaneous esophageal perforation'' or ''esophageal rupture'') refers to an [[esophagus|esophageal]] rupture secondary to forceful [[vomiting]]. Originally described in 1724 by Dutch physician/botanist [[Herman Boerhaave]], it is a rare condition with high mortality. The syndrome was described after the case of a Dutch admiral, Baron Jan von Wassenaer, who died of the condition.

==== Factor V Leiden (1994) ====
[[Factor V Leiden]] is an inherited disorder of blood clotting. It is a variant of human [[factor V]] that causes a hypercoagulability disorder. It is named after the city Leiden, where it was first identified by R. Bertina, et al., in 1994.

=== Microbiology ===
==== Blood cells (1658) ====

In 1658 Dutch naturalist [[Jan Swammerdam]] was the first person to observe [[red blood cells]] under a microscope and in 1695, [[microscopist]] [[Antoni van Leeuwenhoek]], also Dutch, was the first to draw an illustration of "red corpuscles", as they were called. No further [[blood cells]] were discovered until 1842 when the [[platelets]] were discovered.

==== Red blood cells (1658) ====
The first person to observe and describe [[red blood cell]]s was Dutch biologist [[Jan Swammerdam]], who had used an early microscope to study the [[blood]] of a frog.

==== Micro-organisms (1670s) ====
A resident of Delft, [[Anton van Leeuwenhoek]], used a high-power single-lens simple microscope to discover the world of [[microorganism|micro-organisms]]. His simple microscopes were made of silver or copper frames, holding hand-ground lenses were capable of magnification up to 275 times. Using these he was the first to observe and describe single-celled organisms, which he originally referred to as ''animalcules'', and which now referred to as [[microorganism|micro-organisms]] or [[microbe]]s.<ref name="Ruestow, Edward G. 1996">Ruestow, Edward G. (1996). ''The Microscope in the Dutch Republic: The Shaping of Discovery''</ref><ref name="Huerta, Robert D. 2003">Huerta, Robert D. (2003). ''Giants of Delft: Johannes Vermeer and the Natural Philosophers: the Parallel Search for Knowledge During the Age of Discovery''</ref><ref name="Burgess, Jeremy 1990 p. 186">Burgess, Jeremy; Marten, Michael; Taylor, Rosemary (1990). ''Under the Microscope: A Hidden World Revealed'', p. 186</ref>
* [[Infusoria]] (1674) – Infusoria is a collective term for minute aquatic creatures including [[ciliate]], [[euglena]], [[paramecium]], [[protozoa]] and unicellular [[algae]] that exist in freshwater ponds. However, in formal classification [[microorganism]] called infusoria belongs to [[Kingdom (biology)|Kingdom]] [[Animal]]ia, [[Phylum]] [[Protozoa]], [[Class (biology)|Class]] [[Ciliates]] (Infusoria). They were first discovered by [[Antoni van Leeuwenhoek]].

[[File:Leishmania donovani 01.png|thumb|right|200px|''[[Leishmania]] donovani'', (a species of protozoa) in a [[bone marrow]] cell]]
* [[Protozoa]] (1674) – In 1674, [[Van Leeuwenhoek]] was the first person to observe and describe [[protozoa]].
* [[Bacteria]] (1676) – The first [[bacteria]] were observed by van Leeuwenhoek in 1676 using his single-lens microscope.<ref name="Maczulak, Anne 2010 p. 12">Maczulak, Anne (2010). ''Allies and Enemies: How the World Depends on Bacteria'', p. 1–2</ref><ref>Fensham, Peter J.; Gunstone, Richard F.; White, Richard Thomas (1994). ''The Content of Science: A Constructivist Approach to Its Teaching and Learning'', p. 164</ref><ref>Haven, Kendall (2007). ''100 Greatest Science Discoveries of All Time'', p. 29–30</ref><ref>Rogers, Kara (2011). ''Bacteria and Viruses (Biochemistry, Cells, and Life)'', p. 1–3</ref><ref>Goes, Frank Joseph (2013). ''The Eye in History'', p. 338–41</ref> He described the creatures he saw as small creatures. The name ''bacterium'' was introduced much later, by [[Christian Gottfried Ehrenberg]] in 1828, derived from the [[Greek word]] βακτηριον meaning "small stick". Because of the difficulty in describing individual bacteria and the importance of their discovery, the study of bacteria is generally that of the study of [[microbiology]].
* [[Sperm cells]] (1677) – Sperm cells were first observed by [[Anton van Leeuwenhoek]] in 1677. The term "[[sperm]]" refers to the male [[reproductive]] [[Cell (biology)|cells]]. A uniflagellar [[sperm]] cell that is [[Motility|motile]] is referred to as a "[[spermatozoon]]", whereas a non-motile [[sperm cell]] is referred to as a "spermatium".
* [[Spermatozoa]] (1677) – A [[spermatozoon]] or spermatozoon (''pl.'' spermatozoa), from the [[ancient Greek]] ''σπερμα'' (seed) and ''ζων'' (alive) and more commonly known as a sperm cell, is the [[ploidy|haploid]] [[cell (biology)|cell]] that is the male [[gamete]]. Sperm cells were first observed by a student of van Leeuwenhoek in 1677. Leeuwenhoek pictured sperm cells with great accuracy.

[[File:Giardia lamblia SEM 8698 lores.jpg|thumb|right|180px|''[[Giardia lamblia|Giardia]]'' trophozoite, [[Scanning electron microscope|SEM]]. The [[trophozoite]] form of [[Giardia]] was first observed in 1681 by Antonie van Leeuwenhoek in his own diarrhea stools.]]
* [[Giardia]] (1681) – ''[[Giardia]]'' is a [[genus]] of [[Anaerobic organism|anaerobic]] [[flagellate]]d [[protozoa]]n [[parasite]]s of the phylum Sarcomastigophora that colonise and reproduce in the small intestines of several [[vertebrates]], causing ''[[giardiasis]]''. Their life cycle alternates between an actively swimming [[trophozoite]] and an infective, resistant [[Microbial cyst|cyst]]. The [[trophozoite]] form of [[Giardia]] was first observed in 1681 by [[Van Leeuwenhoek]] during observation of his own stool.<ref name="ErlandsenMeyer1984">{{cite book|author1=Stanley L. Erlandsen|author2=Ernest A. Meyer|title=Giardia and Giardiasis: Biology, Pathogenesis, and Epidemiology|url=https://books.google.com/books?id=F8IIzx8PaWAC&pg=PA131|date=1 March 1984|publisher=Springer|isbn=978-0-306-41539-5|pages=131–}}</ref>

[[Volvox]] (1700)- [[Volvox]] is a [[genus]] of [[chlorophyte]]s, a type of [[green algae]]. It forms spherical [[Colony (biology)|colonies]] of up to 50,000 cells. They live in a variety of [[freshwater]] habitats, and were first reported by Van Leeuwenhoek in 1700.

==== Biological nitrogen fixation (1885) ====
Biological [[nitrogen fixation]] was discovered by [[Martinus Beijerinck]] in 1885.

==== Rhizobium (1888) ====
''[[Rhizobium]]'' is a [[genus]] of [[Gram-negative]] [[soil]] [[bacteria]] that [[nitrogen fixation|fix nitrogen]]. Rhizobium forms an [[endosymbiont|endosymbiotic]] [[nitrogen fixation|nitrogen fixing]] association with roots of [[legumes]] and ''Parasponia''. [[Martinus Beijerinck]] in the [[Netherlands]] was the first to isolate and cultivate a [[microorganism]] from the nodules of legumes in 1888. He named it ''Bacillus radicicola'', which is now placed in ''[[Bergey's Manual of Determinative Bacteriology]]'' under the genus Rhizobium.

==== Spirillum (first isolated sulfate-reducing bacteria) (1895) ====
[[Martinus Beijerinck]] discovered the phenomenon of bacterial [[Sulfate-reducing bacteria|sulfate reduction]], a form of [[anaerobic respiration]]. He learned that bacteria could use [[sulfate]] as a terminal [[electron acceptor]], instead of oxygen. He isolated and described ''[[Spirillum|Spirillum desulfuricans]]'' (now called ''[[Desulfovibrio desulfuricans]]''<ref>{{cite web |url=https://lpsn.dsmz.de/genus/desulfovibrio |title=Genus ''Desulfovibrio'' |last1=Jean |first1=Euzeby |publisher=[[List of Prokaryotic names with Standing in Nomenclature]] |accessdate=6 November 2014}}</ref>), the first known [[sulfate-reducing bacterium]].

==== Concept of virus (1898) ====
In 1898 Beijerinck coined the term "virus" to indicate that the causal agent of [[tobacco mosaic disease]] was non-bacterial. Beijerinck discovered what is now known as the [[tobacco mosaic virus]]. He observed that the agent multiplied only in cells that were dividing and he called it a [[contagium vivum fluidum]] (''contagious living fluid''). Beijerinck's discovery is considered to be the beginning of [[virology]].<ref>[[Charles Calisher|Calisher, Charles H.]]; Horzinek, M.C. (1999). ''100 Years of Virology: The Birth and Growth of a Discipline'', p. 1–8</ref><ref>Creager, Angela N. H. (2002). ''The Life of a Virus: Tobacco Mosaic Virus as an Experimental Model, 1930–1965'', p. 20–27</ref><ref>Feest, Uljana; Steinle, Friedrich (2003). ''Scientific Concepts and Investigative Practice'', p. 204–08</ref><ref>Trigiano, Robert N.; Windham, Mark T.; Windham, Alan S. (2004). ''Plant Pathology: Concepts and Laboratory Exercises'', p. 35</ref><ref>Dimmock, Nigel; Easton, Andrew; Leppard, Keith (2007). ''Introduction to Modern Virology'', p. 4–5</ref><ref>Haven, Kendall (2007). ''100 Greatest Science Discoveries of All Time'', p. 101–02</ref><ref>Devasahayam, H. Lewin (2009). ''Illustrated Plant Pathology: Basic Concepts'', p. 7</ref><ref>Shors, Teri (2013). ''Understanding Viruses'', p. 628</ref><ref>Pommerville, Jeffrey C. (2014). ''''Fundamentals of Microbiology'', p. 453</ref><ref>Grove, David (2014). ''Tapeworms, Lice, and Prions: A Compendium of Unpleasant Infections'', p. 429</ref>

==== Azotobacter (1901) ====
''[[Azotobacter]]'' is a [[genus]] of usually [[Motility|motile]], oval or spherical [[bacteria]] that form thick-walled [[cyst]]s and may produce large quantities of capsular [[Mucus|slime]]. They are aerobic, free-living soil [[Microorganism|microbes]] which play an important role in the [[nitrogen cycle]] in nature, binding atmospheric [[nitrogen]], which is inaccessible to plants, and releasing it in the form of [[ammonium]] ions into the soil. Apart from being a [[model organism]], it is used by humans for the production of [[biofertilizer]]s, [[food additive]]s, and some [[biopolymer]]s. The first representative of the genus, ''Azotobacter chroococcum'', was discovered and described in 1901 by the Dutch [[microbiologist]] and botanist [[Martinus Beijerinck]].

==== Enrichment culture (1904) ====
Beijerinck is credited with developing the first [[enrichment culture]], a fundamental method of studying microbes from the environment.

=== Physics ===
==== 31 equal temperament (1661) ====

Division of the [[octave]] into 31 steps arose naturally out of Renaissance [[music theory]]; the lesser [[diesis]]  –  the ratio of an octave to three major thirds, 128:125 or 41.06 cents  –  was approximately a [[interval (music)|fifth]] of a tone and a third of a [[semitone]]. In 1666, [[Lemme Rossi]] first proposed an equal temperament of this order. Shortly thereafter, having discovered it independently, scientist [[Christiaan Huygens]] wrote about it also. Since the standard system of [[musical tuning|tuning]] at that time was [[quarter-comma meantone]], in which the fifth is tuned to 5<sup>1/4</sup>, the appeal of this method was immediate, as the fifth of 31-et, at 696.77 cents, is only 0.19 cent wider than the fifth of quarter-comma meantone. Huygens not only realized this, he went farther and noted that 31-ET provides an excellent approximation of septimal, or [[limit (music)|7-limit]] harmony. In the twentieth century, physicist, music theorist and composer [[Adriaan Fokker]], after reading Huygens's work, led a revival of interest in this system of tuning which led to a number of compositions, particularly by Dutch composers. Fokker designed the [[Fokker organ]], a 31-tone equal-tempered organ, which was installed in [[Teylers Museum|Teyler's Museum]] in [[Haarlem]] in 1951.

==== Polarization of light (1678) ====
In 1678, [[Christiaan Huygens|Huygens]] discovered the [[polarization of light]] by [[double refraction]] in [[calcite]].<ref>Turner, Gerard L'Estrange (1983). ''Nineteenth-century Scientific Instruments'', p. 149</ref><ref>Driggers, Ronald G. (2003). ''Encyclopedia of Optical Engineering, Volume 1'', p. 183</ref><ref>Coulson, Kinsell (2012). ''Solar and Terrestrial Radiation: Methods and Measurements'', p. 12</ref>

==== Huygens' principle (concepts of the wavefront and wavelet) (1690) ====
In his ''[[Treatise on light]]'', Huygens showed how [[Snell's law]] of sines could be explained by, or derived from, the [[wave]] nature of [[light]], using the [[Huygens–Fresnel principle]].

==== Bernoulli's principle (1738) ====
[[Bernoulli's principle]] was discovered by Dutch-Swiss mathematician and physicist [[Daniel Bernoulli]] and named after him. It states that for an [[inviscid flow]], an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.

==== Brownian motion (1785) ====
In 1785, Ingenhousz described the irregular movement of [[coal dust]] on the surface of alcohol and therefore has a claim as discoverer of what came to be known as [[Brownian motion]].

==== Buys Ballot's law (1857) ====
The law takes its name from Dutch meteorologist [[C. H. D. Buys Ballot]], who published it in the ''Comptes Rendus'', in November 1857. While [[William Ferrel]] first theorized this in 1856, Buys Ballot was the first to provide an [[empirical validation]]. The law states that in the [[Northern Hemisphere]], if a person stands with his back to the wind, the low pressure area will be on his left, because wind travels counterclockwise around low pressure zones in that [[Hemisphere of the Earth|hemisphere]]. this is approximately true in the higher latitudes and is reversed in the [[Southern Hemisphere]].

==== Foundations of molecular physics (1873) ====
Spearheaded by [[Ernst Mach|Mach]] and [[Wilhelm Ostwald|Ostwald]], a strong philosophical current that denied the existence of [[molecules]] arose towards the end of the 19th century. The molecular existence was considered unproven and the molecular hypothesis unnecessary. At the time Van der Waals' thesis was written (1873), the [[molecular structure]] of [[fluids]] had not been accepted by most physicists, and [[liquid]] and [[vapor]] were often considered as chemically distinct. But [[Johannes Diderik van der Waals|Van der Waals]]'s work affirmed the reality of molecules and allowed an assessment of their size and [[Van der Waals forces|attractive strength]].<ref>Johannes van der Waals (''The equation of state for gases and liquids'', Nobel Lecture, 12 December 1910)</ref> By comparing [[Van der Waals equation of state|his equation of state]] with experimental data, Van der Waals was able to obtain estimates for the actual size of molecules and the strength of [[Van der Waals forces|their mutual attraction]].<ref>Sengers, Johanna Levelt (2002), p. 16</ref> By [[Van der Waals constants (data page)|introducing parameters]] characterizing molecular size and attraction in constructing his [[equation of state]], Van der Waals set the tone for [[molecular physics]] ([[molecular dynamics]] in particular) of the 20th century. That molecular aspects such as size, shape, attraction, and [[intermolecular force|multipolar interactions]] should form the basis for mathematical formulations of the thermodynamic and transport properties of [[fluids]] is presently considered an axiom.<ref>Sengers, Johanna Levelt (2002), p. 255–56</ref>

==== Van der Waals equation of state (1873) ====
In 1873, [[J. D. van der Waals]] introduced the [[Van der Waals equation of state|first equation of state]] derived by the assumption of a finite volume occupied by the constituent [[molecules]].<ref>Van der Waals, J. D. (1873). ''On the Continuity of the Gaseous and Liquid States'' (Doctoral dissertation, Universiteit Leiden).</ref> The [[Van der Waals equation]] is generally regarded as the first somewhat realistic [[equation of state]] (beyond the ideal gas law). Van der Waals noted the [[ideal gas|non-ideality]] of [[gases]] and attributed it to the existence of [[intermolecular interaction|molecular]] or atomic interactions. His new formula revolutionized the study of equations of state, and was most famously continued via the [[Redlich-Kwong equation of state]] (1949) and the Soave modification of Redlich-Kwong. While the Van der Waals equation is definitely superior to the [[ideal gas law]] and does predict the formation of a [[liquid phase]], the agreement with experimental data is limited for conditions where the liquid forms. Except at higher pressures, the [[real gas]]es do not obey [[Van der Waals equation]] in all ranges of pressures and temperatures. Despite its limitations, the equation has historical importance, because it was the first attempt to model the behaviour of [[real gas]]es.

==== Van der Waals forces (1873) ====
The [[van der Waals force]]s are named after the scientist who first described them in 1873. [[Johannes Diderik van der Waals]] noted the non-ideality of gases and attributed it to the existence of molecular or atomic interactions. They are forces that develop between the atoms inside molecules and keep them together.<ref>Parsegian, V. Adrian (2005). ''Van der Waals Forces: A Handbook for Biologists, Chemists, Engineers, and Physicists'', p. 2</ref> The Van der Waals forces between molecules, much weaker than [[chemical bonds]] but present universally, play a role in fields as diverse as [[supramolecular chemistry]], [[structural biology]], [[polymer science]], [[nanotechnology]], [[surface science]], and [[condensed matter physics]].

==== Van der Waals radius (1873) ====
The [[Van der Waals radius]], ''r''{{sub|w}}, of an [[atom]] is the radius of an imaginary hard [[sphere]] which can be used to model the atom for many purposes. It is named after [[Johannes Diderik van der Waals]], winner of the 1910 [[Nobel Prize in Physics]], as he was the first to recognise that atoms were not simply [[Point (geometry)|points]] and to demonstrate the physical consequences of their size through the [[Van der Waals equation|van der Waals equation of state]].

==== Law of corresponding states (1880) ====
The [[Theorem of corresponding states|law of corresponding states]] was first suggested and formulated by van der Waals in 1880. This showed that the van der Waals equation of state can be expressed as a simple function of the critical pressure, critical volume and critical temperature. This general form is applicable to all substances. The compound-specific constants a and b in the original equation are replaced by universal (compound-independent) quantities. It was this law that served as a guide during experiments which ultimately led to the [[liquefaction]] of [[hydrogen]] by [[James Dewar]] in 1898 and of [[helium]] by [[Heike Kamerlingh Onnes]] in 1908.

==== Lorentz ether theory (1892) ====
[[Lorentz ether theory]] has its roots in [[Hendrik Lorentz]]'s "theory of electrons", which was the final point in the development of the classical [[aether (classical element)|aether]] theories at the end of the 19th and at the beginning of the 20th century. Lorentz's initial theory created in 1892 and 1895 was based on a completely motionless aether. Many aspects of Lorentz's theory were incorporated into [[special relativity]] with the works of [[Albert Einstein]] and [[Hermann Minkowski]].

==== Lorentz force law (1892) ====
[[File:Lorentz force particle.svg|180px|thumb|[[Lorentz force]] '''F''' on a [[charged particle]] (of [[electric charge|charge]] ''q'') in motion (instantaneous velocity '''v'''). The [[electric field|'''E''' field]] and [[magnetic field|'''B''' field]] vary in space and time.]]
In 1892, [[Hendrik Lorentz]] derived the modern form of the formula for the electromagnetic force which includes the contributions to the total force from both the electric and the magnetic fields.<ref>Wadhwani, Navina (2007). ''Electricity And Magnetism'', p. 78</ref><ref>Andriesse, Cornelis Dirk (2008). ''Dutch Messengers: A History of Science Publishing, 1930–1980'', p. 12</ref><ref>Miyazaki, Terunobu; Jin, Hanmin (2012). ''The Physics of Ferromagnetism'', p. 3</ref> In many textbook treatments of classical electromagnetism, the [[Lorentz force law]] is used as the ''definition'' of the electric and magnetic fields '''E''' and '''B'''.<ref name=Jackson20>See, for example, Jackson p. 777–78.</ref><ref>{{cite book|title=Gravitation|author1=J.A. Wheeler |author2=C. Misner |author3=K.S. Thorne |publisher=W.H. Freeman & Co|year=1973|pages=72–73|isbn=978-0-7167-0344-0}}. These authors use the Lorentz force in tensor form as definer of the [[electromagnetic tensor]] ''F'', in turn the fields '''E''' and '''B'''.</ref><ref>{{cite book|title=Electromagnetism|url=https://archive.org/details/electromagnetism0000gran|url-access=registration|edition=2nd|author1=I.S. Grant |author2=W.R. Phillips |author3=Manchester Physics |publisher=John Wiley & Sons|year=2008|page=[https://archive.org/details/electromagnetism0000gran/page/n135 122]|isbn=978-0-471-92712-9}}</ref> To be specific, the Lorentz force is understood to be the following empirical statement:

:''The electromagnetic force '''F''' on a [[test charge]] at a given point and time is a certain function of its charge ''q'' and velocity '''v''', which can be parameterized by exactly two vectors '''E''' and '''B''', in the functional form'':

::<math>\mathbf{F}=q(\mathbf{E}+\mathbf{v}\times\mathbf{B})</math>

==== Abraham–Lorentz force (1895) ====
In the physics of [[electromagnetism]], the [[Abraham–Lorentz force]] (also ''Lorentz-Abraham force'') is the [[recoil]] [[force]] on an [[acceleration|accelerating]] [[charged particle]] caused by the particle emitting [[electromagnetic radiation]]. It is also called the ''radiation reaction force'' or the ''self force''.

==== Lorentz transformation (1895) ====
In physics, the [[Lorentz transformation]] (or [[Lorentz transformations]]) is named after the Dutch physicist [[Hendrik Lorentz]]. It was the result of attempts by Lorentz and others to explain how the speed of [[light]] was observed to be independent of the [[frame of reference|reference frame]], and to understand the symmetries of the laws of [[electromagnetism]]. The Lorentz transformation is in accordance with [[special relativity]], but was derived before special relativity. Early approximations of the transformation were published by Lorentz in 1895. In 1905, [[Henri Poincaré|Poincaré]] was the first to recognize that the transformation has the properties of a [[group (mathematics)|mathematical group]], and named it after Lorentz.

==== Lorentz contraction (1895) ====
In physics, [[length contraction]] (more formally called [[Lorentz contraction]] or [[Lorentz–FitzGerald contraction]] after [[Hendrik Lorentz]] and [[George Francis FitzGerald|George FitzGerald]]) is the phenomenon of a decrease in length measured by the observer, of an object which is traveling at any non-zero velocity relative to the observer. This contraction is usually only noticeable at a substantial fraction of the [[speed of light]].

==== Lorentz factor (1895) ====
The [[Lorentz factor]] or ''Lorentz term'' is the factor by which time, length, and [[relativistic mass]] change for an object while that object is moving. It is an expression which appears in several equations in [[special relativity]], and it arises from deriving the [[Lorentz transformation]]s. The name originates from its earlier appearance in [[Lorentz ether theory|Lorentzian electrodynamics]] – named after the [[Netherlands|Dutch]] physicist [[Hendrik Lorentz]].<ref>[http://www.nap.edu/html/oneuniverse/motion_knowledge_concept_12.html One universe], by [[Neil deGrasse Tyson]], [[Charles Tsun-Chu Liu]], and Robert Irion.</ref>

==== Zeeman effect (1896) ====
[[File:EinsteinZeemanEhrenfest.jpg|thumb|right|180px|Discoverer of the [[Zeeman effect]], [[Pieter Zeeman]] with [[Albert Einstein]] and [[Paul Ehrenfest]] in his laboratory in Amsterdam (circa 1920).]]
The [[Zeeman effect]], named after the [[Netherlands|Dutch]] physicist [[Pieter Zeeman]], is the effect of splitting a [[spectral line]] into several components in the presence of a static [[magnetic field]]. It is analogous to the [[Stark effect]], the splitting of a spectral line into several components in the presence of an [[electric field]]. Also similar to the Stark effect, transitions between different components have, in general, different intensities, with some being entirely forbidden (in the [[dipole]] approximation), as governed by the [[selection rule]]s.

Since the distance between the Zeeman sub-levels is a function of the magnetic field, this effect can be used to measure the magnetic field, e.g. that of the [[Sun]] and other [[star]]s or in laboratory [[Plasma (physics)|plasmas]].
The Zeeman effect is important in applications such as [[nuclear magnetic resonance]] spectroscopy, [[electron spin resonance]] spectroscopy, [[magnetic resonance imaging]] (MRI) and [[Mössbauer spectroscopy]]. It may also be utilized to improve accuracy in [[atomic absorption spectroscopy]].

A theory about the [[magnetic sense]] of birds assumes that a protein in the retina is changed due to the Zeeman effect.<ref>[http://rsif.royalsocietypublishing.org/content/3/9/583.full The magnetic compass mechanisms of birds and rodents are based on different physical principles]. Journal of the Royal Society</ref>

When the spectral lines are absorption lines, the effect is called ''inverse Zeeman effect''.

==== Liquid helium (liquefaction of helium) (1908) ====
[[File:2 Helium.png|thumb|Liquid helium in a cup.]]
[[Helium]] was first liquefied ([[liquid helium]]) on 10 July 1908, by Dutch physicist [[Heike Kamerlingh Onnes]]. With the production of [[liquid helium]], it was said that "the coldest place on Earth" was in [[Leiden]].<ref>Matricon, Jean; Waysand, Georges (1994). ''The Cold Wars: A History of Superconductivity'', p. 23</ref><ref>Shachtman, Tom (1999). ''Absolute Zero and the Conquest of Cold'', p. 186</ref><ref>Blundell, Stephen J. (2009). ''Superconductivity: A Very Short Introduction'', p. 23–24</ref>

==== Superconductivity (1911) ====
[[File:Ehrenfest Lorentz Bohr Kamerlingh Onnes.jpg|thumb|right|[[Paul Ehrenfest]], [[Hendrik Lorentz]] and [[Niels Bohr]] visit [[Heike Kamerlingh Onnes]] in the cryogenic lab (where Onnes discovered the [[phenomenon]] of [[superconductivity]] in 1911).]]

[[Superconductivity]], the ability of certain materials to conduct electricity with little or no resistance, was discovered by Dutch physicist [[Heike Kamerlingh Onnes]].<ref>Vidali, Gianfranco (1993). ''Superconductivity: The Next Revolution?'', p. 30–38</ref><ref>Matricon, Jean; Waysand, Georges (1994). ''The Cold Wars: A History of Superconductivity''</ref><ref>Shachtman, Tom (1999). ''Absolute Zero and the Conquest of Cold'', p. 233</ref><ref>Buckel, Werner; Kleiner, Reinhold (2004). ''Superconductivity: Fundamentals and Applications''</ref>

==== Einstein–de Haas effect (1910s) ====
The [[Einstein–de Haas effect]] or the ''Richardson effect'' (after [[Owen Willans Richardson]]), is a physical phenomenon delineated by [[Albert Einstein]] and [[Wander Johannes de Haas]] in the mid-1910s, that exposes a relationship between [[magnetism]], [[angular momentum]], and the [[Electron magnetic moment|spin]] of elementary particles.

==== Debye model (1912) ====
In [[thermodynamics]] and [[solid state physics]], the [[Debye model]] is a method developed by [[Peter Debye]] in 1912 for estimating the [[phonon]] contribution to the [[specific heat]] (heat capacity) in a [[solid]].<ref>{{cite journal |first=Peter |last=Debye |title=Zur Theorie der spezifischen Waerme |journal=[[Annalen der Physik]] |location=Leipzig |volume=39 |issue=4 |pages=789–839 |year=1912 |doi= 10.1002/andp.19123441404 |bibcode=1912AnP...344..789D |url=https://zenodo.org/record/1424256 }}</ref> It treats the [[oscillation|vibrations]] of the [[Crystal structure#Classification|atomic lattice]] (heat) as [[phonon]]s in a box, in contrast to the [[Einstein solid|Einstein model]], which treats the solid as many individual, non-interacting [[quantum harmonic oscillator]]s. The Debye model correctly predicts the low temperature dependence of the heat capacity.

==== De Sitter precession (1916) ====
The [[geodetic effect]] (also known as geodetic precession, [[de Sitter precession]] or [[De Sitter precession|de Sitter effect]]) represents the effect of the curvature of [[spacetime]], predicted by [[general relativity]], on a vector carried along with an orbiting body. The geodetic effect was first predicted by [[Willem de Sitter]] in 1916, who provided relativistic corrections to the Earth–Moon system's motion.

==== De Sitter space and anti-de Sitter space (1920s) ====
In mathematics and physics, a [[de Sitter space]] is the analog in [[Minkowski space]], or spacetime, of a sphere in ordinary, [[Euclidean space]]. The ''n''-dimensional de Sitter space, denoted dS<sub>''n''</sub>, is the [[Lorentzian manifold]] analog of an [[n-sphere|''n''-sphere]] (with its canonical [[Riemannian metric]]); it is maximally [[symmetric]], has constant positive [[scalar curvature|curvature]], and is [[simply connected]] for ''n'' at least 3. The de Sitter space, as well as the [[anti-de Sitter space]] is named after [[Willem de Sitter]] (1872–1934), professor of astronomy at [[Leiden University]] and director of the [[Leiden Observatory]]. Willem de Sitter and [[Albert Einstein]] worked in the 1920s in [[Leiden]] closely together on the spacetime structure of our universe. De Sitter space was discovered by [[Willem de Sitter]], and, at the same time, independently by [[Tullio Levi-Civita]].

==== Van der Pol oscillator (1920) ====
In [[dynamical system]]s, a [[Van der Pol oscillator]] is a non-conservative [[oscillator]] with non-linear [[Damping ratio|damping]]. It was originally proposed by Dutch physicist [[Balthasar van der Pol]] while he was working at Philips in 1920. Van der Pol studied a [[differential equation]] that describes the circuit of a [[vacuum tube]]. It has been used to model other phenomenon such as human [[Cardiac cycle|heartbeats]] by colleague Jan van der Mark.

==== Kramers' opacity law (1923) ====
[[Kramers' opacity law]] describes the [[opacity (optics)|opacity]] of a medium in terms of the ambient [[density]] and [[temperature]], assuming that the opacity is dominated by [[ionization|bound-free absorption]] (the absorption of light during ionization of a bound [[electron]]) or [[free-free absorption]] (the absorption of light when scattering a free ion, also called [[bremsstrahlung]]).<ref>Phillips (1999), p. 92.</ref> It is often used to model [[radiative transfer]], particularly in [[stellar atmosphere]]s.<ref>Carroll (1996), p. 274–276.</ref> The relation is named after the [[Dutch people|Dutch]] [[physicist]] [[Hendrik Kramers]], who first derived the form in 1923.<ref name="Carroll274">Carroll (1996), p. 274.</ref>

==== Electron spin (1925) ====
In 1925, Dutch physicists [[George Eugene Uhlenbeck]] and [[Samuel Goudsmit]] co-discovered the concept of [[electron spin]], which posits an intrinsic [[angular momentum]] for all electrons.

==== Solidification of helium (1926) ====
In 1926, Onnes' student, Dutch physicist [[Willem Hendrik Keesom]], invented a method
to freeze [[liquid helium]] and was the first person who was able to solidify the noble gas.

==== Ehrenfest theorem (1927) ====
The [[Ehrenfest theorem]], named after the Austrian-born [[Dutch Jew|Dutch-Jew]] theoretical physicist [[Paul Ehrenfest]] at [[Leiden University]].

==== De Haas–van Alphen effect (1930) ====
The [[de Haas–van Alphen effect]], often abbreviated to dHvA, is a [[quantum mechanical]] effect in which the [[magnetic moment]] of a pure metal [[crystal]] oscillates as the intensity of an applied [[magnetic field]] B is increased. It was discovered in 1930 by [[Wander Johannes de Haas]] and his student P. M. van Alphen.

==== Shubnikov–de Haas effect (1930) ====
The [[Shubnikov–de Haas effect]] (ShdH) is named after Dutch physicist [[Wander Johannes de Haas]] and Russian physicist [[Lev Shubnikov]].

==== Kramers degeneracy theorem (1930) ====
In quantum mechanics, the [[Kramers theorem|Kramers degeneracy theorem]] states that for every energy eigenstate of a [[T-symmetry|time-reversal symmetric]] system with half-integer total spin, there is at least one more eigenstate with the same energy. It was first discovered in 1930 by [[Hendrik Anthony Kramers|H. A. Kramers]]<ref>Kramers, H. A., Proc. Amsterdam Acad. 33, 959 (1930)</ref> as a consequence of the [[Breit equation]].

==== Minnaert resonance frequency (1933) ====
In 1933, [[Marcel Minnaert]] published a solution for the [[Acoustics|acoustic]] [[resonance frequency]] of a single [[Liquid bubble|bubble]] in [[water]], the so-called [[Minnaert resonance]]. The [[Minnaert resonance]] or [[Minnaert frequency]]<ref>{{Citation |last=Minnaert |first=M. |author-link=Marcel Minnaert |year=1933 |title=On musical air-bubbles and the sound of running water |journal=Philosophical Magazine |volume=16 |issue=104 |pages=235–48 |doi=10.1080/14786443309462277|s2cid=120320419 }}</ref> is the [[acoustic resonance|acoustic]] [[resonance]] frequency of a single bubble in an infinite domain of water (neglecting the effects of [[surface tension]] and [[Viscosity|viscous]] [[attenuation]]).

==== Casimir effect (1948) ====
In quantum field theory, the [[Casimir effect]] and the [[Casimir–Polder force]] are physical forces arising from a quantized field. Dutch physicists [[Hendrik Casimir]] and [[Dirk Polder]] at Philips Research Labs proposed the existence of a force between two polarizable atoms and between such an atom and a conducting plate in 1947. After a conversation with [[Niels Bohr]] who suggested it had something to do with zero-point energy, Casimir alone formulated the theory predicting a force between neutral conducting plates in 1948; the former is called the Casimir–Polder force while the latter is the Casimir effect in the narrow sense.

==== Tellegen's theorem (1952) ====
[[Tellegen's theorem]] is one of the most powerful theorems in [[network theory]]. Most of the energy distribution theorems and extremum principles in network theory can be derived from it. It was published in 1952 by [[Bernard Tellegen]]. Fundamentally, Tellegen's theorem gives a simple relation between magnitudes that satisfy [[Kirchhoff's circuit laws|Kirchhoff's laws]] of [[electrical circuit theory]].

==== Stochastic cooling (1970s) ====
In the early 1970s [[Simon van der Meer]], a Dutch particle physicist at [[CERN]], discovered this technique to concentrate proton and anti-proton beams, leading to the discovery of the [[W particle|W]] and [[Z particle]]s. He won the 1984 [[Nobel Prize in Physics]] together with [[Carlo Rubbia]].

==== Renormalization of gauge theories (1971) ====
In 1971, [[Gerardus 't Hooft]], who was completing his PhD under the supervision of Dutch theoretical physicist [[Martinus Veltman]], [[renormalization|renormalized]] [[Yang–Mills theory]]. They showed that if the symmetries of Yang–Mills theory were to be realized in the [[Spontaneous symmetry breaking|spontaneously broken]] mode, referred to as the Higgs mechanism, then Yang–Mills theory can be renormalized.<ref>{{cite journal |author1=G. 't Hooft |author2=M. Veltman |name-list-style=amp| title=Regularization and Renormalization of Gauge Fields | journal=Nuclear Physics B | volume=44 |issue=1 | year=1972 | pages=189–219 |bibcode = 1972NuPhB..44..189T |doi = 10.1016/0550-3213(72)90279-9 |hdl=1874/4845 |url=https://repositorio.unal.edu.co/handle/unal/81144 |hdl-access=free }}</ref><ref>[http://igitur-archive.library.uu.nl/phys/2005-0622-155148/13877.pdf Regularization and Renormalization of Gauge Fields by 't Hooft and Veltman (PDF)] {{webarchive|url=https://web.archive.org/web/20120707134940/http://igitur-archive.library.uu.nl/phys/2005-0622-155148/13877.pdf |date= 7 July 2012 }}</ref> Renormalization of Yang–Mills theory is considered as a major achievement of twentieth century physics.

==== Holographic principle (1993) ====
The [[holographic principle]] is a property of [[string theory|string theories]] and a supposed property of [[quantum gravity]] that states that the description of a volume of [[space]] can be thought of as encoded on a [[Boundary (topology)|boundary]] to the region – preferably a [[light-like]] boundary like a [[apparent horizon|gravitational horizon]]. In 1993, Dutch theoretical physicist [[Gerard 't Hooft]] proposed what is now known as the [[holographic principle]]. It was given a precise string-theory interpretation by [[Leonard Susskind]]<ref name=SusskindArXiv>{{cite journal |title=The World as a Hologram |last=Susskind |first=Leonard |doi=10.1063/1.531249 |date=1995 |journal=Journal of Mathematical Physics |volume=36 |issue=11 |pages=6377–96|arxiv=hep-th/9409089 |bibcode = 1995JMP....36.6377S |s2cid=17316840 }}</ref> who combined his ideas with previous ones of 't Hooft and [[Charles Thorn]].<ref name=SusskindArXiv /><ref>{{cite conference |first=Charles B. |last=Thorn |title=Reformulating string theory with the 1/N expansion |conference=International A.D. Sakharov Conference on Physics |location=Moscow |date=27–31 May 1991 |isbn=978-1-56072-073-7 |arxiv=hep-th/9405069 |pages=447–54|bibcode=1994hep.th....5069T }}</ref>

== References ==
{{reflist}}

== External links ==
* [https://web.archive.org/web/20150322003219/http://www.dailydutchinnovation.com/about/ Daily Dutch Innovation]

{{Inventions}}
{{Netherlands topics}}

{{DEFAULTSORT:Dutch Inventions And Discoveries}}
[[Category:Lists of inventions or discoveries]]
[[Category:Netherlands history-related lists|Discoveries]]
[[Category:History of science and technology in the Netherlands|.]]
[[Category:Science and technology in the Dutch Republic]]
[[Category:Science and technology in the Netherlands]]
[[Category:Dutch exploration in the Age of Discovery]]
[[Category:Netherlandic studies|List of Dutch discoveries]]
[[Category:Discoveries]]