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Following the Path of Discovery Repeat Famous Experiments and Inventions |
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There is evidence that primitive batteries were used in Iraq and Egypt as early as 200 B.C. for electroplating and precious metal gilding. In 1748, Benjamin Franklin coined the term "battery" to describe an array of charged glass plates. Around the 1790s, through numerous observations and experiments, Luigi Galvani, an Italian professor of anatomy, caused muscular contraction in a frog by touching its nerves with an electrostatically charged metal. Later, he was able to cause muscular contraction by touching the nerve with different metals without a source of electrostatic charge. He concluded that animal tissue contained an innate vital force, which he termed "animal electricity." In fact, it was Volta's famous disagreement with Galvani's theory of animal electricity that led Volta, in 1800, to build the voltaic pile to prove that electricity did not come from the animal tissue but was generated by the contact of different metals in a moist environment. Most historians attribute the invention of the battery to Alessandro Volta since his voltaic pile was the first battery that produced a reliable, steady current of electricity. Volta’s invention was to give rise to electrochemistry, electromagnetism and the modern applications of electricity. Also Galvani's idea of animal electricity did not prove useless. Galvani’s research was soon to develop into electrophysiology and modern biology. After Volta is called the "volt", the unit of electromotive force; after Galvani is called the galvanometer - an instrument for detecting and measuring small electric currents. Basically, Volta’s pile was a messy stack (pile) of discs made of two types of metal - one silver, the other zinc. The discs were separated from each other by a piece of cloth or cardboard that had been soaked in salt water (brine). Volta found that this wet stack of “dissimilar metals” created a small electric current, and this current could be drawn off through wires and used for experiments. However, a pile could generate only a small voltage of 1-2 volts. Several piles - a “battery” of them - could be assembled side by side and connected to each other with metal strips to create a high power energy source. In some of his variant pile experiments Volta used a solution of sulfuric acid as the electrolyte in order to achieve better results. In high concentrations, this acid can be very dangerous. If it gets on the skin or in the eyes, it can cause very serious burns and can permanently blind. To repeat Volta's experiment use more benign substances like copper sulfate, for example or brine. As a rule: this experiment should be performed under the supervision of teachers or adults familiar with safety procedures. Read carefully the experiment links and ensure that you understand the basic principals. Brows further the web and consult your local library, your teachers and other knowledgeable adults and experts. Build Your Own Voltaic Pile The Volta's Pile - Giorgio Carboni Battery Chemistry: Voltaic Pile - howstuffworks Batteries - David A. Katz Variables in a Voltaic Pile - MadSci Network The Voltaic Pile - Cartage How to Make a Voltaic Pile - ehow.com Building a Voltaic Pile - Ms. Ehrlich's Web Page Voltaic Pail Controversies Origin of Power in the Voltaic Pile - Bibliomania.com Nineteenth-Century Theories of the Voltaic Pile - Helge Kragh Alessandro Volta Biographies Count Alessandro Volta - Energy Quest Alessandro Volta - Corrosion Doctors Alessandro Volta - about.com Alessandro Volta - Wikipedia Allesandro Volta - l' uomo e lo scienziato Alessandro Volta - The Catholic Encyclopedia Alessandro Volta - The Great Idea Finder Count Alessandro Giuseppe Antonio Anastasio - Famous Italians Alessandro Volta - Cartage Alessandro Volta - Nancy D. Lewis Electrochemistry and Battery History Electrochemistry: Early History - Dr. Edwin Thall Battery History - about.com Electricity Timeline - Nancy D. Lewis Electric Battery - The Great Idea Finder Spark Museum Instruments for Natural Philosophy - Thomas B. Greenslade Voltaic pile Clipart - Educational Technology Clearinghouse Bioelectricity - Electro.Patent-Invent Science Fair Projects Battery & Cell Science Fair Projects and Experiments
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