Science

=== 19th century ===
{{Main|19th century in science}}[[File:Darwin Tree 1837.png|left|thumb|The first diagram of an [[Phylogenetic tree|evolutionary tree]] made by [[Charles Darwin]] in 1837|alt=Sketch of a map with captions]]
During the nineteenth century, many distinguishing characteristics of contemporary modern science began to take shape. These included the transformation of the life and physical sciences, frequent use of precision instruments, emergence of terms such as "biologist", "physicist", "scientist", increased professionalization of those studying nature, scientists gained cultural authority over many dimensions of society, industrialization of numerous countries, thriving of popular science writings and emergence of science journals.<ref name="Lightman 19th">{{cite book|last1= Lightman|first1= Bernard|editor1-last= Shank|editor1-first= Michael|editor2-last= Numbers|editor2-first= Ronald|editor3-last= Harrison|editor3-first= Peter|title= Wrestling with Nature: From Omens to Science|date= 2011|publisher= University of Chicago Press|location= Chicago|isbn= 978-0-226-31783-0|page= 367|chapter= 13. Science and the Public}}</ref> During the late 19th century, [[psychology]] emerged as a separate discipline from philosophy when [[Wilhelm Wundt]] founded the first laboratory for psychological research in 1879.<ref name="leahey2018">{{cite book |last=Leahey |first=Thomas Hardy |title=A History of Psychology: From Antiquity to Modernity |date=2018 |publisher=Routledge |isbn=978-1-138-65242-2 |edition=8th |location=New York, NY |pages=219–253 |chapter=The psychology of consciousness}}</ref>

During the mid-19th century, [[Charles Darwin]] and [[Alfred Russel Wallace]] independently proposed the theory of evolution by [[natural selection]] in 1858, which explained how different plants and animals originated and evolved. Their theory was set out in detail in Darwin's book ''[[On the Origin of Species]]'', published in 1859.<ref name="padian2008">{{cite journal | last = Padian | first = Kevin | title = Darwin's enduring legacy | journal = Nature | volume = 451 | issue = 7179 | pages = 632–634 |year = 2008 | doi = 10.1038/451632a | pmid = 18256649 | bibcode = 2008Natur.451..632P | doi-access = free }}</ref> Separately, [[Gregor Mendel]] presented his paper, "[[Experiments on Plant Hybridization]]" in 1865,<ref>{{Cite book|last=Henig|first=Robin Marantz |author-link=Robin Marantz Henig |url=https://archive.org/details/monkingardenlost00heni|title=The monk in the garden: the lost and found genius of Gregor Mendel, the father of genetics|date=2000|pages=134–138}}</ref> which outlined the principles of biological inheritance, serving as the basis for modern genetics.<ref name="miko2008">{{cite journal | last = Miko | first = Ilona | title = Gregor Mendel's principles of inheritance form the cornerstone of modern genetics. So just what are they? | journal = Nature Education | volume = 1 | issue = 1 | pages = 134 |year = 2008 | url = https://www.nature.com/scitable/topicpage/gregor-mendel-and-the-principles-of-inheritance-593/ | access-date = May 9, 2021 | archive-date = July 19, 2019 | archive-url = https://web.archive.org/web/20190719224056/http://www.nature.com/scitable/topicpage/gregor-mendel-and-the-principles-of-inheritance-593 | url-status = live }}</ref>

Early in the 19th century, [[John Dalton]] suggested the modern [[atomic theory]], based on Democritus's original idea of indivisible particles called ''atoms''.<ref name="In Search of El Dorado: John Dalton">{{cite journal |last1=Rocke |first1=Alan J. |year=2005 |title=In Search of El Dorado: John Dalton and the Origins of the Atomic Theory |journal=Social Research |volume=72 |issue=1 |pages=125–158 |doi=10.1353/sor.2005.0003 |jstor=40972005|s2cid=141350239 }}</ref> The laws of [[conservation of energy]], [[conservation of momentum]] and [[conservation of mass]] suggested a highly stable universe where there could be little loss of resources. However, with the advent of the [[steam engine]] and the [[industrial revolution]] there was an increased understanding that not all forms of energy have the same [[energy quality|energy qualities]], the ease of conversion to useful [[Work (thermodynamics)|work]] or to another form of energy.<ref name=Reichl /> This realization led to the development of the laws of [[thermodynamics]], in which the free energy of the universe is seen as constantly declining: the [[entropy]] of a closed universe increases over time.{{efn|name= HelmholtzGibbsGuthLinde|1= Whether the universe is closed or open, or the [[shape of the universe]], is an open question. The 2nd law of thermodynamics,<ref name=Reichl >{{cite book |last=Reichl |first=Linda |author-link=Linda Reichl |date=1980 |title=A Modern Course in Statistical Physics |url= |location= |publisher=Edward Arnold |isbn=0-7131-2789-9}}</ref>{{rp|9}}<ref name=Rao>{{cite book|last=Rao|first=Y. V. C.|title=Chemical Engineering Thermodynamics|publisher=Universities Press|isbn=978-81-7371-048-3|year=1997|page=158}}</ref> and the 3rd law of thermodynamics<ref name=3rdlaw >{{cite journal |doi=10.1016/j.aop.2016.07.031 |title=Bounded energy exchange as an alternative to the third law of thermodynamics |year=2016 |last1=Heidrich |first1=M. |journal=Annals of Physics |volume=373 |pages=665–681 |bibcode=2016AnPhy.373..665H |url=https://zenodo.org/record/999547 |access-date=May 29, 2022 |archive-date=January 15, 2019 |archive-url=https://web.archive.org/web/20190115182230/https://zenodo.org/record/999547 |url-status=live }}</ref> imply the [[heat death of the universe]] if the universe is a closed system, but not necessarily for an expanding universe.}}

The [[electromagnetic theory]] was established in the 19th century by the works of [[Hans Christian Ørsted]], [[André-Marie Ampère]], [[Michael Faraday]], [[James Clerk Maxwell]], [[Oliver Heaviside]], and [[Heinrich Hertz]]. The new theory raised questions that could not easily be answered using Newton's framework. The discovery of [[X-ray]]s inspired the discovery of [[radioactivity]] by [[Henri Becquerel]] and [[Marie Curie]] in 1896,<ref>{{cite book |last=Mould |first=Richard F. |title=A century of X-rays and radioactivity in medicine: with emphasis on photographic records of the early years |date=1995 |publisher=Inst. of Physics Publ. |isbn=978-0-7503-0224-1 |edition=Reprint. with minor corr |location=Bristol |page=12}}</ref> Marie Curie then became the first person to win two [[Nobel Prize|Nobel prizes]].<ref name="psb113">{{cite book |last=Estreicher |first=Tadeusz |title=Polski słownik biograficzny, vol. 4 |title-link=Polski słownik biograficzny |year=1938 |page=113 |language=pl |chapter=Curie, Maria ze Skłodowskich |author-link=Tadeusz Estreicher}}</ref> In the next year came the discovery of the first subatomic particle, the [[electron]].<ref name="thomson">{{cite journal |last=Thomson |first=J.J. |year=1897 |title=Cathode Rays |url=https://zenodo.org/record/1431235 |url-status= |journal=[[Philosophical Magazine]] |volume=44 |issue=269 |pages=293–316 |doi=10.1080/14786449708621070 |archive-url= |archive-date= |access-date=February 24, 2022|url-access= }}</ref>