Search results
Results from the WOW.Com Content Network
1st century AD – Pliny in his Natural History records the story of a shepherd Magnes who discovered the magnetic properties of some iron stones, "it is said, made this discovery, when, upon taking his herds to pasture, he found that the nails of his shoes and the iron ferrel of his staff adhered to the ground". [6]
For example, in 1820 Hans Christian Ørsted of Copenhagen discovered the deflecting effect of an electric current traversing a wire upon a suspended magnetic needle. [11] This discovery gave a clue to the subsequently proved intimate relationship between electricity and magnetism which was promptly followed up by Ampère who some months later ...
The magnet was made of 18 turns of bare copper wire (insulated wire had not yet been invented). [1] William Sturgeon (/ ˈ s t ɜːr dʒ ə n /; 22 May 1783 – 4 December 1850) was an English electrical engineer and inventor who made the first electromagnet and the first practical electric motor.
When ferrimagnets are exposed to an external magnetic field, they display what is called magnetic hysteresis, where magnetic behavior depends on the history of the magnet. They also exhibit a saturation magnetization M rs {\displaystyle M_{\text{rs}}} ; this magnetization is reached when the external field is strong enough to make all the ...
One of the earliest known references to lodestone's magnetic properties was made by 6th century BC Greek philosopher Thales of Miletus, [12] whom the ancient Greeks credited with discovering lodestone's attraction to iron and other lodestones. [13] The name magnet may come from lodestones found in Magnesia, Anatolia. [14]
In the late 1920s, Gregory Breit and Merle Tuve at the Bureau of Terrestrial Magnetism constructed a working device that used varying magnetic fields to accelerate electrons. Their device placed two solenoidal magnets next to one another and fired electrons from a gun at the outer edge of the magnetic field. As the field was increased, the ...
The history of geomagnetism is concerned with the history of the study of Earth's magnetic field. It encompasses the history of navigation using compasses, studies of the prehistoric magnetic field (archeomagnetism and paleomagnetism), and applications to plate tectonics. Magnetism has been known since prehistory, but knowledge of the Earth's ...
These similarities led Lord Kelvin to propose a formal definition of magnetic field [2] in 1851: [4] Any space at every point of which there is a finite magnetic force is called ‘a field of magnetic force’ or (magnetic being understood) simply ‘a field of force,’ or sometimes ‘a magnetic field’.