Editing Electricity (section)

==Electricity and the natural world==
===Physiological effects===
{{Main|Electrical injury}}

A voltage applied to a human body causes an electric current through the tissues, and although the relationship is non-linear, the greater the voltage, the greater the current.<ref name=tleis>
{{Citation
| first = Nasser | last = Tleis
| title = Power System Modelling and Fault Analysis
| publisher = Elsevier
| year = 2008
| pages = 552–54
| isbn = 978-0-7506-8074-5}}
</ref> The threshold for perception varies with the supply frequency and with the path of the current, but is about 0.1&nbsp;mA to 1&nbsp;mA for mains-frequency electricity, though a current as low as a microamp can be detected as an [[electrovibration]] effect under certain conditions.<ref>
{{Citation
| first = Sverre | last = Grimnes
| title = Bioimpedance and Bioelectricity Basic
| publisher = Academic Press
| year = 2000
| pages = 301–09
| isbn = 0-12-303260-1}}
</ref> If the current is sufficiently high, it will cause muscle contraction, [[fibrillation]] of the heart, and [[burn|tissue burns]].<ref name=tleis/> The lack of any visible sign that a conductor is electrified makes electricity a particular hazard. The pain caused by an electric shock can be intense, leading electricity at times to be employed as a method of [[torture]].<ref>
{{Citation
| first1 = J.H. | last1 = Lipschultz
| first2 = M.L.J.H. | last2 = Hilt
| title = Crime and Local Television News
| publisher = Lawrence Erlbaum Associates
| year = 2002
| page = 95
| isbn = 0-8058-3620-9}}
</ref> Death caused by an electric shock—[[electrocution]]—is still used for [[capital punishment|judicial execution]] in some US states, though its use had become very rare by the end of the 20th century.<ref>{{Cite journal |last1=Linders |first1=Annulla |last2=Kansal |first2=Shobha Pai |last3=Shupe |first3=Kyle |last4=Oakley |first4=Samuel |date=2021 |title=The Promises and Perils of Technological Solutions to the Troubles with Capital Punishment |url=http://journals.sagepub.com/doi/10.1177/0160597620932892 |journal=Humanity & Society |language=en |volume=45 |issue=3 |pages=384–413 |doi=10.1177/0160597620932892 |s2cid=225595301 |issn=0160-5976}}</ref>

===Electrical phenomena in nature===
{{main|Electrical phenomena}}
[[File:Electric-eel2.jpg|thumb|The [[electric eel]], ''Electrophorus electricus'']]

Electricity is not a human invention, and may be observed in several forms in nature, notably [[lightning]]. Many interactions familiar at the macroscopic level, such as [[touch]], [[friction]] or [[chemical bond]]ing, are due to interactions between electric fields on the atomic scale. The [[Earth's magnetic field]] is due to the [[dynamo theory|natural dynamo]] of circulating currents in the planet's core.<ref>
{{citation
|first=Thérèse |last=Encrenaz|author-link=Thérèse Encrenaz
|title=The Solar System
|page=217
|publisher=Springer
|isbn=3-540-00241-3
|year=2004}}
</ref> Certain crystals, such as [[quartz]], or even [[sugar]], generate a potential difference across their faces when pressed.<ref name=crystallography>
{{citation
|first1=José |last1=Lima-de-Faria
|first2=Martin J.| last2= Buerger
|title=Historical Atlas of Crystallography
|journal=Zeitschrift für Kristallographie
|volume=209
|issue=12
|page=67
|publisher=Springer
|isbn=0-7923-0649-X
|year=1990|bibcode=1994ZK....209.1008P
|doi=10.1524/zkri.1994.209.12.1008a
}}
</ref> This phenomenon is known as [[piezoelectricity]], from the [[Greek language|Greek]] ''piezein'' (πιέζειν), meaning to press, and was discovered in 1880 by [[Pierre Curie|Pierre]] and [[Jacques Curie]]. The effect is reciprocal: when a piezoelectric material is subjected to an electric field it changes size slightly.<ref name=crystallography/>

Some organisms, such as [[shark]]s, are able to detect and respond to changes in electric fields, an ability known as [[electroreception]],<ref name=Biodynamics>
{{citation
| first = Vladimir & Tijana 
| last = Ivancevic
| title = Natural Biodynamics
| page = 602
| publisher = World Scientific
| year = 2005
| isbn = 981-256-534-5}}
</ref> while others, termed [[electrogenic]], are able to generate voltages themselves to serve as a predatory or defensive weapon; these are [[electric fish]] in different orders.<ref name=Electroreception/> The order [[Gymnotiformes]], of which the best-known example is the [[electric eel]], detect or stun their prey via high voltages generated from modified muscle cells called [[electrocytes]].<ref name=Electroreception/><ref name=morris/> All animals transmit information along their cell membranes with voltage pulses called [[action potential]]s, whose functions include communication by the nervous system between [[neuron]]s and [[muscle]]s.<ref name="neural science">
{{citation
| first1 = E.
| last1 = Kandel
| first2 = J.
| last2 = Schwartz
| first3 = T.
| last3 = Jessell
| title = Principles of Neural Science
| pages = [https://archive.org/details/isbn_9780838577011/page/27 27–28]
| year = 2000
| publisher = McGraw-Hill Professional
| isbn =0-8385-7701-6
| url = https://archive.org/details/isbn_9780838577011/page/27
}}
</ref> An electric shock stimulates this system and causes muscles to contract.<ref>{{citation
| first = Paul 
| last = Davidovits
| title = Physics in Biology and Medicine
| pages = 204–05
| year = 2007
| publisher = Academic Press
| isbn = 978-0-12-369411-9}}</ref> Action potentials are also responsible for coordinating activities in certain plants.<ref name="neural science"/>