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Galvanic Cell
A galvanic cell or voltaic cell, named after the scientists Luigi Galvani and Alessandro Volta, respectively, is an electrochemical cell in which an electric current is generated from spontaneous Oxidation-Reduction reactions. A common apparatus generally consists of two different metals, each immersed in separate beakers containing their respective metal ions in solution that are connected by a salt bridge or separated by a porous membrane. Volta was the inventor of the voltaic pile, the first Battery (electricity), electrical battery. In common usage, the word "battery" has come to include a single galvanic cell, but a battery properly consists of multiple cells. History In 1780, Luigi Galvani discovered that when two different metals (e.g., copper and zinc) are in contact and then both are touched at the same time to two different parts of a muscle of a frog leg, to close the circuit, the frog's leg contracts. He called this "bioelectricity, animal electricity". The frog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galvanic Cell With No Cation Flow
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Galvanic (after Luigi Galvani) may refer to: * Galvanic anode * Galvanic bath * Galvanic cell * Galvanic corrosion * Galvanic current * Galvanic isolation * Galvanic series * Galvanic skin response * Galvanic vestibular stimulation * Galvanism * Galvanization * Operation Galvanic, World War II attack which included the Battle of Tarawa See also * List of forms of electricity named after scientists This is a list of forms of electricity named after scientists. The terms in this list are mostly archaic usages but are found in many 19th and early 20th-century publications. Adjectives ; faradic : Of electricity that is alternating, especial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials depending on the type of battery. The electrophore, invented by Johan Wilcke, was an early version of an electrode used to study static electricity. Anode and cathode in electrochemical cells Electrodes are an essential part of any battery. The first electrochemical battery made was devised by Alessandro Volta and was aptly named the Voltaic cell. This battery consisted of a stack of copper and zinc electrodes separated by brine-soaked paper disks. Due to fluctuation in the voltage provided by the voltaic cell it wasn't very practical. The first practical battery was invented in 1839 and named the Daniell cell after John Frederic Daniell. Still making use of the zinc–copper electrode combination. Since then many more batteries have be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daniell Cell
The Daniell cell is a type of electrochemical cell invented in 1836 by John Frederic Daniell, a British chemist and meteorologist, and consists of a copper pot filled with a copper (II) sulfate solution, in which is immersed an unglazed earthenware container filled with sulfuric acid and a zinc electrode. He was searching for a way to eliminate the hydrogen bubble problem found in the voltaic pile, and his solution was to use a second electrolyte to consume the hydrogen produced by the first. Zinc sulfate may be substituted for the sulfuric acid. The Daniell cell was a great improvement over the existing technology used in the early days of battery development. A later variant of the Daniell cell called the gravity cell or crowfoot cell was invented in the 1860s by a Frenchman named Callaud and became a popular choice for electrical telegraphy. The Daniell cell is also the historical basis for the contemporary definition of the volt, which is the unit of electromotive force in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semi-permeable Membrane
Semipermeable membrane is a type of biological or synthetic, polymeric membrane that will allow certain molecules or ions to pass through it by osmosis. The rate of passage depends on the pressure, concentration, and temperature of the molecules or solutes on either side, as well as the permeability of the membrane to each solute. Depending on the membrane and the solute, permeability may depend on solute size, solubility, properties, or chemistry. How the membrane is constructed to be selective in its permeability will determine the rate and the permeability. Many natural and synthetic materials which are rather thick are also semipermeable. One example of this is the thin film on the inside of the egg. Biological membranes are selectively permeable, with the passage of molecules controlled by facilitated diffusion, passive transport or active transport regulated by proteins embedded in the membrane. Biological membranes An example of a biological semi-permeable membrane is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Half-cell
In electrochemistry, a half-cell is a structure that contains a conductive electrode and a surrounding conductive electrolyte separated by a naturally occurring Helmholtz double layer. Chemical reactions within this layer momentarily pump electric charges between the electrode and the electrolyte, resulting in a potential difference between the electrode and the electrolyte. The typical anode reaction involves a metal atom in the electrode being dissolved and transported as a positive ion across the double layer, causing the electrolyte to acquire a net positive charge while the electrode acquires a net negative charge. The growing potential difference creates an intense electric field within the double layer, and the potential rises in value until the field halts the net charge-pumping reactions. This self-limiting action occurs almost instantly in an isolated half-cell; in applications two dissimilar half-cells are appropriately connected to constitute a Galvanic cell. A standa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enthalpy
Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant pressure, which is conveniently provided by the large ambient atmosphere. The pressure–volume term expresses the work required to establish the system's physical dimensions, i.e. to make room for it by displacing its surroundings. The pressure-volume term is very small for solids and liquids at common conditions, and fairly small for gases. Therefore, enthalpy is a stand-in for energy in chemical systems; bond, lattice, solvation and other "energies" in chemistry are actually enthalpy differences. As a state function, enthalpy depends only on the final configuration of internal energy, pressure, and volume, not on the path taken to achieve it. In the International System of Units (SI), the unit of measurement for enthalpy is the joule. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galvanic Cell Labeled
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Galvanic (after Luigi Galvani) may refer to: * Galvanic anode * Galvanic bath * Galvanic cell * Galvanic corrosion * Galvanic current * Galvanic isolation * Galvanic series * Galvanic skin response * Galvanic vestibular stimulation * Galvanism * Galvanization * Operation Galvanic, World War II attack which included the Battle of Tarawa See also * List of forms of electricity named after scientists This is a list of forms of electricity named after scientists. The terms in this list are mostly archaic usages but are found in many 19th and early 20th-century publications. Adjectives ; faradic : Of electricity that is alternating, especial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parthia
Parthia ( peo, 𐎱𐎼𐎰𐎺 ''Parθava''; xpr, 𐭐𐭓𐭕𐭅 ''Parθaw''; pal, 𐭯𐭫𐭮𐭥𐭡𐭥 ''Pahlaw'') is a historical region located in northeastern Greater Iran. It was conquered and subjugated by the empire of the Medes during the 7th century BC, was incorporated into the subsequent Achaemenid Empire under Cyrus the Great in the 6th century BC, and formed part of the Hellenistic Seleucid Empire following the 4th-century-BC conquests of Alexander the Great. The region later served as the political and cultural base of the Eastern Iranian Parni people and Arsacid dynasty, rulers of the Parthian Empire (247 BC – 224 AD). The Sasanian Empire, the last state of pre-Islamic Iran, also held the region and maintained the seven Parthian clans as part of their feudal aristocracy. Name The name "Parthia" is a continuation from Latin ', from Old Persian ', which was the Parthian language self-designator signifying "of the Parthians" who were an Iranian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baghdad Battery
The Baghdad Battery is the name given to a set of three artifacts which were found together: a ceramic pot, a tube of copper, and a rod of iron. It was discovered in present-day Khujut Rabu, Iraq in 1936, close to the metropolis of Ctesiphon, the capital of the Parthian (150 BC – 223 AD) and Sasanian (224–650 AD) empires, and it is believed to date from either of these periods. Its origin and purpose remain unclear. It was hypothesized by Wilhelm König, at the time director of the National Museum of Iraq, that the object functioned as a galvanic cell, possibly used for electroplating, or some kind of electrotherapy, but there is no electroplated object known from this period, and the claims are near universally rejected by archaeologists. An alternative explanation is that it functioned as a storage vessel for sacred scrolls. Physical description and dating The artifacts consist of a terracotta pot approximately tall, with a mouth, containing a cylinder made of a rolled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm König
Wilhelm König (born in Vienna) was an Austrian archaeologist and painter. A painter by profession, in 1931, König was elected assistant to the German leader of the Baghdad Antiquity Administration with the title of a "Direktor". At the excavation of a Parthian settlement in modern day Khujut Rabu (near Baghdad, Iraq), he discovered the alleged Baghdad Battery. In February 1939, he returned to Vienna, due to blood poisoning, where he published a book ''Im verlorenen Paradies. Neun Jahre Irak''. Controversy In March 2012, Professor Elizabeth Stone, of Stony Brook University, an expert on Iraqi archaeology, returning from one of the first archaeological expeditions in Iraq since 20 years, stated that she does not know a single archaeologist, who believed that this was a "''real'' battery".Prof. Stone's statement, listed as a 'red flag' amon5 red flags why it was not a battery(with sources, on Archaeology Fantasies website) Works''Neun Jahre Irak''Brünn, Münster, Wien 1940 Wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromotive Force
In electromagnetism and electronics, electromotive force (also electromotance, abbreviated emf, denoted \mathcal or ) is an energy transfer to an electric circuit per unit of electric charge, measured in volts. Devices called electrical ''transducers'' provide an emf by converting other forms of energy into electrical energy. Other electrical equipment also produce an emf, such as batteries, which convert chemical energy, and generators, which convert mechanical energy. This energy conversion is achieved by physical forces applying physical work on electric charges. However, electromotive force itself is not a physical force, and for the current ISO/IEC standards consider the term deprecated, favoring the names source voltage or source tension instead (denoted U_s). An electronic–hydraulic analogy may view emf as the mechanical work done to water by a pump, which results in a pressure difference (analogous to voltage). In electromagnetic induction, emf can be defined ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anion
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons while an anion is a negatively charged ion with more electrons than protons. Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
