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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^{[citation needed]} that attempted to explain how electricity is generated in an electric battery or, as it was then called, the Voltaic pile. 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, φυσικός (physikos), natural, and φύσις (physis), nature) is the science of the natural world, dealing with the fundamental constituents of the universe, the forces they exert on one another, and the results produced by these forces. ... 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. ...

Explanation

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 unavoiable 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 (derived from alchemy) is the science of matter at or near the atomic scale. ... Properties The electron is a lightweight fundamental subatomic particle that carries a negative electric charge. ... Properties In chemistry and physics, an atom (Greek άτομον meaning indivisible) is the smallest possible particle of a chemical element that retains its chemical properties. ... Rust, the most familiar example of corrosion. ...

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[1] 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. ... Count Alessandro Giuseppe Antonio Anastasio Volta (February 18, 1745 - March 5, 1827) was an Italian physicist known especially for the development of the electric battery in 1800. ... 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. 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. ...

References

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