Jan 28
History Of Magnets
History of Magnetism and Electricity
600 BC - Lodestone
The magnetic properties of natural ferric ferrite (Fe3O4) stones (lodestones) were described by Greek philosophers.
600 BC - Electric Charge
Amber is a yellowish, translucent mineral. As early as 600 BC the Greek philosopher, Aristophanes was aware of its peculiar property: when rubbed with a piece of fur, amber develops the ability to attract small pieces of material such as feathers. For centuries this strange, inexplicable property was thought to be unique to amber. This strange effect remained a mystery for over 2000 years, until, around AD 1600, Dr William Gilbert investigated the reactions of amber and magnets and first recorded the word 'Electric' in a report on the theory of magnetism.
Later in, in 1895, H.A. Lorentz developed the Electron Theory. We now know that there are three ways to generate electricity: Static, Electrochemical and Electromagnetic Induction.
1175 - First Reference to a Compass
Alexander Neckem an English monk of St. Albans describes the workings of a compass.
1269 - First Detailed Description of a Compass
Petrus Peregrinus de Marincourt, a French Crusader, describes a floating compass and a compass with a pivot point.
1600 - Static Electricity (De Magnete)
In the 16th century, William Gilbert(1544-1603), the Court Physician to Queen Elizabeth I, proved that many other substances are electric (from the Greek word for amber, elektron) and that they have two electrical effects. When rubbed with fur, amber acquires resinous electricity; glass, however, when rubbed with silk, acquires vitreous electricity. Electricity repels the same kind and attracts the opposite kind of electricity. Scientists thought that the friction actually created the electricity (their word for charge). They did not realize that an equal amount of opposite electricity remained on the fur or silk. Dr. William Gilbert, realized that a force was created, when a piece of amber (resin) was rubbed with wool and attracted light objects. In describing this property today, we say that the amber is "electrified" or possesses and "electric charge". These terms are derived from the Greek word "electron" meaning amber and from this, the term "electricity" was developed. It was not until the end of the 19th century that this "something" was found to consist of negative electricity, known today as electrons.
Gilbert also studied magnetism and in 1600 wrote "De magnete" which gave the first rational explanation to the mysterious ability of the compass needle to point north-south: the Earth itself was magnetic. "De Magnete" opened the era of modern physics and astronomy and started a century marked by the great achievements of Galileo, Kepler, Newton and others.
Gilbert recorded three ways to magnetize a steel needle: by touch with a loadstone; by cold drawing in a North-South direction; and by exposure for a long time to the Earth's magnetic field while in a North-South orientation.
1660 - Static Electricity Generator
Otto von Guericke invents a crude machine for producing static electricity.
1729 - Conductors and Nonconductors
Stephen Gray describes that power possessed by one electrified body could be passed to another by connecting them.
1734 - Electrical Attraction and Repulsion
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