André-Marie Ampère (1775-1836)
André-Marie Ampère (1775-1836), a French physicist, founded the science of electrodynamics now known as electromagnetism.
Danish physicist Hans Christian Ørsted discovered in 1820 that a magnetic needle is deflected when the current in a nearby wire varies - a phenomenon establishing a relationship between electricity and magnetism.
During September and October 1820, Ampère, influenced by Ørsted's discovery, performed a series of experiments designed to elucidate the exact nature of the relationship between electric current-flow and magnetism, as well as the relationships governing the behavior of electric currents in various types of conductors. Among others, Ampère showed that two parallel wires carrying electric currents magnetically attract each other if the currents are in the same direction and repel if the currents are in opposite directions.
This experiments led Ampère to formulate his famous law of electromagnetism, called after him Ampère's law, that describes mathematically the magnetic force between two electrical currents.
His investigations, reported weekly before the Académie des Sciences, established the new science of electrodynamics.
He was also first person to develop measuring techniques for electricity. Ampère built an instrument utilizing a free moving needle to measure the flow of electricity. The later refinement of this instrument is known as galvanometer. Basically, a galvanometer is an instrument where a free pivoting coil and an attached needle are placed in the magnetic field of a permanent magnet. When an electric current is passed through the coil it experiences a torque due to the interaction of the current with the magnetic field. As a result the coil pivots and the needle is deflected proportionally to the current passing through the coil.
The unit of electric current, ampere, is called after André-Marie Ampère.
Ampère's law related experiments and background
Ampère's Law - Electro.Patent-Invent
Magnets and Magnetism - Science Fair Projects and Experiments
Ampere's Law Basics - Exploratorium
Current Balance - PASCO
The 19th Century Current Balance - J. W. Dooley
Ampère's Law - Ben Waugh
The New Science of Electrodynamics: 1820 - Sparkmuseum
Ampere's Law - HyperPhysics
Current Experiment - Dave Trapp
Ampère's Experiments - Richard Fitzpatrick
Ampère's Law - Richard Fitzpatrick
Measurement of Electric Current - cartage.org
Build Your Own Galvanometer
Current Detector (Galvanometer) - Matt Dayley and Keith Holbert
Build a Real Scientific Galvanometer - Thomas J. Wdowiak, The Birmingham News
Running on Sunshine - Engineers Week
Why can't a Galvanometer Be Highly Sensitive - MadSci Network
Measuring Electrical Circuits - Science 9!
André-Marie Ampère biographies and general resources
André-Marie Ampère - Patent-Invent.com
