File:Resistivity geometry.png|A piece of resistive material with electrical contacts on both ends.
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File:Newtons cradle animation.ogv|Like balls in a [[Newton's cradle]], electrons in a metal quickly transfer energy from one terminal to another, despite their own negligible movement.
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File:Superconductivity 1911.gif|Original data from the 1911 experiment by [[Heike Kamerlingh Onnes]] showing the resistance of a mercury wire as a function of temperature. The abrupt drop in resistance is the superconducting transition.
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File:Lightning over Oradea Romania 3.jpg|[[Lightning]] is an example of plasma present at Earth's surface. Typically, lightning discharges 30,000 amperes at up to 100 million volts, and emits light, radio waves, and X-rays. Plasma temperatures in lightning might approach 30,000 kelvin (29,727 °C) (53,540 °F), or five times hotter than the temperature at the sun surface, and electron densities may exceed 1024 m−3.