Editing Electricity (section)

===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"/>