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In physics, contact tension (also known as the contact electromotive force, the contact potential, or the Volta effect), is an obsolete scientific theory that attempted to explain how electricity is generated in an electric battery or, as it was then called, the Voltaic pile.^[1] Wikipedia does not have an article with this exact name. ... In the late-18th century, scientists developed sensitive instruments for detecting electrification, otherwise known as electrostatic charge imbalance. ... Physics (from the Greek, (phúsis), nature and (phusiké), knowledge of nature) is the science concerned with the discovery and understanding of the fundamental laws which govern matter, energy, space and time. ... An obsolete scientific theory is a scientific theory that was once commonly accepted but (for whatever reason) is no longer considered the most complete description of reality by mainstream science; or a falsifiable theory which has been shown to be false. ... Four double-A batteries In science and technology, a battery is a device that stores energy and makes it available in an electrical form. ... A copper-zinc Voltaic pile The Voltaic pile was the first modern electric battery, invented by Alessandro Volta in 1800. ...

History

The theory held that static electricity was generated by means of contact between dissimilar materials, and was in close agreement with the principles of static electricity as then understood. It was eventually replaced by the current theory of electrochemistry, namely, that electricity is generated by the action of chemistry and the exchange of electrons between atoms making up the battery. An important fact leading to the rejection of the theory of contact tension was the observation that corrosion, that is, the chemical degradation of the battery, seemed unavoidable with its use, and that the more electricity was drawn from the battery, the faster the corrosion proceeded. Static electricity is a class of phenomena involving the net charge present on an object; typically referring to charged object with voltages of sufficient magnitude to produce visible attraction, repulsion, and sparks. ... English chemists John Daniell (left) and Michael Faraday (right), both credited to be founders of electrochemistry as known today. ... Chemistry (from Greek χημεία khemeia[1] meaning alchemy) is the science of matter at the atomic to molecular scale, dealing primarily with collections of atoms, such as molecules, crystals, and metals. ... The electron is a fundamental subatomic particle that carries an electric charge. ... Properties For other uses, see Atom (disambiguation). ... Corrosion is deterioration of intrinsic properties in a material due to reactions with its environment. ...

In fact, the Volta effect does correspond to a weak electric potential developed by the contact of different metals. This effect was first discovered by Alessandro Volta, and can be measured using a capacitance electroscope[2] comprised of different metals. However, the actual effect is not sufficiently strong to account for the action of electric batteries. Electric potential is the potential energy per unit of charge associated with a static (time-invariant) electric field, also called the electrostatic potential, typically measured in volts. ... Volta redirects here. ... A capacitance electroscope is a type of electroscope in which a dielectric material is sandwiched between the leaves of the electroscope. ...

A number of high voltage dry piles were invented between the early 1800s and the 1830s in an attempt to determine the answer to this question, and specifically to support Volta’s hypothesis of contact tension. The Oxford Electric Bell is one example. In electrical engineering High voltage refers to a voltage which is high. ... The Dry-Pile (also known as the Duluc pile or Zamboni pile) is a high voltage low current semi-permanent electric battery developed in the early 1800s and constructed from silver foil, zinc foil, and paper. ... The Oxford Electric Bell or Clarendon Dry Pile is located in the foyer of the Clarendon Laboratory at the University of Oxford. ...

References

• ↑  Willem Hackmann, The Enigma of Volta's "Contact Tension" and the Development of the "Dry Pile", (undated, 2000 or later)