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Discovery of Magnets

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History of Magnets

The history of magnets goes back to 600 B.C. but it was only in the 20th century that scientists began to understand it and the discovery of magnets applications began.

Magnetism was most likely first discovered in a type of magnetite called lodestone, which is made up of iron oxide, a chemical compound made up of iron and oxygen. The first known users of this mineral, which they called a magnet because of its ability to attract other pieces of the same material and iron, were the ancient Greeks.

William Gilbert (1540-1603), an Englishman, was the first to use scientific methods to investigate the phenomenon of magnetism. He also found that the Earth is a weak magnet in and of itself. Carl Friedrich Gauss, a German, conducted the first theoretical studies into the nature of the Earth's magnetism (1777-1855).

The inverse square law of force states that the attractive force between two magnetized objects is directly proportional to the product of their fields and inversely proportional to the square of the distance between them.

Quantitative studies of the history of magnetism and magnetic phenomena began in the 18th century with Frenchman Charles Coulomb (1736-1806), who developed the inverse square law of force, which states that “the attractive force between two magnetized objects is directly proportional to the product of their individual fields and inversely proportional to the square of the distance”.

Hans Christian Oersted (1777-1851), a Danish physicist, was the first to propose a link between electricity and magnetism. Experiments on the interactions of magnetic and electric fields were carried out by Frenchman Andre Marie Ampere (1775-1836) and Englishman Michael Faraday (1791-1869), but it was the Scotsman James Clerk Maxwell (1831-1879) who laid the theoretical foundation for electromagnetism in the 19th century by demonstrating that electricity and magnetism are the same things.

The work and theoretical models of two Germans, Ernest Ising (1900- ) and Werner Heisenberg (1900- ), are responsible for our current understanding of magnetism, which is based on the theory of electron motion and interactions in atoms (known as quantum electrodynamics) (1901-1976). Werner Heisenberg was a key figure in the development of modern quantum mechanics.


Origin of Magnets

Magnetism is caused by two kinds of electron motions in atoms: one is the motion of electrons in an orbit around the nucleus, which is similar to the motion of planets in our solar system around the sun, and the other is the spin of electrons around their axis, which is similar to the rotation of the Earth around its axis.

Each electron acquires a magnetic moment as a result of its orbital and spin motions, causing it to behave like a tiny magnet. The rotational force experienced by a magnet in a magnetic field of unit strength acting perpendicular to its magnetic axis defines its magnetic moment.

Because of the Pauli exclusion principle, which states that each electronic orbit can only be occupied by two electrons of opposite spin, the magnetic moment of the electrons cancels out in a large fraction of the elements. However, several so-called transition metal atoms, such as iron, cobalt, and nickel, have magnetic moments that are not cancelled, making them common magnetic materials. The magnetic moment in these transition metal elements is derived solely from the spin of the electrons.

The effect of electron orbital motion is not cancelled in the rare earth elements (which start with lanthanum in the sixth row of the Periodic Table of Elements), so both spin and orbital motion contribute to the magnetic moment. Cerium, neodymium, samarium, and europium are examples of magnetic rare earth elements.

Magnetic moments can be found in a wide range of chemical compounds containing transition and rare earth elements, in addition to metals and alloys. Metal oxides, which are chemically bonded compositions of metals with oxygen, are among the most common magnetic compounds.

According to a fundamental law of electromagnetism, a magnetic field is created by the passage of an electric current, the Earth's geomagnetic field is the result of electric currents produced by the slow convective motion of its liquid core.

The Earth's core, according to this model, should be electrically conductive enough to allow for the generation and transmission of an electric current. The resulting geomagnetic field will be dipolar, similar to the magnetic field produced by a conventional magnet, with lines of magnetic force lying in approximate planes passing through the geomagnetic axis.


Who was the Founder of Magnet?

Magnets make the world go-’round, and tales of their discovery and application appear to come from all corners of the globe.


Greece

Magnes, a Greek shepherd, is said to have been tending his sheep in Magnesia, a region of northern Greece, around 4,000 years ago. When he took a step forward, the nails holding his shoe together and the metal tip of his staff became stuck to the rock he was standing on! He began digging, intrigued, and found the first known lodestone. Magnesia or Magnesia was probably the inspiration for the name "magnetite" given to lodestones.


Rome

Pliny the Elder, a Roman author, and naturalist who undertook important scientific research for the then-Roman Emperor Vespasian in the early AD years described a hill made of a stone that attracted iron. Pliny attributed magnetite's powers to magic, igniting a flurry of superstitious theories about the material, including the possibility that ships that had gone missing at sea had been drawn to magnetic islands. Pliny died in the eruption of Pompeii, which is unrelated but curious.


Scandinavia

With a large lodestone deposit in Scandinavia and insufficient light to navigate ships by during the winter, the Vikings had every incentive to put lodestone's magnetic properties to good use. The Vikings are believed to have used a compass-like tool made of lodestone and iron as early as 1,000 B.C. Viking sailors used a magnetized iron needle inserted into a piece of straw and float in a bowl of water to signify north and south, according to legend.


China

The Chinese may have invented a mariner's compass that was similar in construction to the Vikings'. As early as 800 A.D., the Chinese used a splinter of lodestone floating on water to navigate. Explorers such as Marco Polo brought the magnetic compass back to Italy, allowing Europeans to finally explore the oceans that the Vikings had been navigating for at least 500 years using their version of the compass.


France

One of the first written accounts of the scientific properties of magnets was authored by French scholar Petrus Peregrinus in the 1200s. The freely pivoting compass needle–a key component of the first dry compass–is depicted and discussed in his report. Peregrinus is said to have composed these works while taking part in a papal-sanctioned crusade/attack on the Italian city of Lucera.


England

William Gilbert, a physician from the United Kingdom, was the first scientist to create a magnet. He found in 1600 that magnets could be forged out of iron and that their magnetic properties could be lost when that iron was heated.


Denmark

Hans Christian Oersted began studying the relationship between electricity and magnetism two hundred years later, in 1820. He proved his theory by placing a magnetic compass near an electrical wire, which caused the compass's accuracy to be thrown off.


A Brief History of Electromagnets/Electromagnetism

1770-90: Cavendish and Coulomb establish foundations of electrostatics

1820: Oersted makes the connection between flowing charge and magnetism.

1820s: Ampere identifies currents as the source of all magnetism (even permanent magnets)

1831: Faraday (also Henry) discovers that time-varying magnetic fields serve as sources for electric fields

1864: Maxwell puts it all together.

1887: Hertz demonstrates the existence of electromagnetic radiation.


History of Electromagnets

Hans Christian Orsted made an unexpected observation while preparing for an evening lecture on April 21, 1820. When the electric current from the battery he was using was turned on and off while he was setting up his materials, he noticed a compass needle deflected away from magnetic north.

This deflection convinced him that magnetic fields, like light and heat, radiate from all sides of a wire carrying an electric current, confirming the existence of a direct relationship between electricity and magnetism.

Orsted did not provide a satisfactory explanation for the phenomenon at the time of its discovery, nor did he attempt to represent it mathematically.

His discoveries sparked a wave of electrodynamics studies across the scientific community. They influenced the development of a single mathematical form to represent the magnetic forces between current-carrying conductors by French physicist André-Marie Ampère. Orsted's discovery was also a significant step toward a unified energy concept.

One of the most important achievements of 19th-century mathematical physics is the unification, which was observed by Michael Faraday, expanded by James Clerk Maxwell, and partially reformulated by Oliver Heaviside and Heinrich Hertz. It had far-reaching implications, one of which was a better understanding of light's nature.

William Sturgeon, an Englishman, was the first person to invent an electromagnet in 1826. It was made up of a coil that created a magnetic field when the current passed through it. There was an iron core in the coil, which increased the magnetic field and led. The magnetic field lines, in this case, are concentrated in the interior of the coil, which has the highest magnetic flux density. With a larger distance outside the coil, it decreases quickly; we can also argue that electromagnets have a large effect when used over short distances.

FAQs on Discovery of Magnets

1. How were magnets first discovered, according to the popular legend?

According to a popular legend from around 4,000 years ago, a Greek shepherd named Magnes was herding his sheep in a region of northern Greece called Magnesia. He discovered that the iron nails in his shoes and the metal tip of his staff were mysteriously sticking to a large black rock. This rock, the first known natural magnet, was later named magnetite, likely after the region of Magnesia or Magnes himself. This naturally magnetic rock is also known as lodestone.

2. What was the first naturally occurring magnet called?

The first naturally occurring magnet discovered is called lodestone. It is a specific type of the mineral magnetite (an iron oxide) that is naturally magnetised. This is the material that ancient civilisations first observed to have the property of attracting iron.

3. Who is known as the 'father of magnetism' and what were his key contributions?

The English physician and scientist William Gilbert (1544-1603) is often called the 'father of magnetism'. His major contributions, published in his work "De Magnete" in 1600, were revolutionary because he was the first to approach the subject with a rigorous scientific method. His key findings include:

  • Proposing that the Earth itself behaves like a giant magnet.
  • Demonstrating that magnets could be forged from iron.
  • Discovering that a magnet's properties could be destroyed by heating it.

4. What is the fundamental origin of magnetism at the atomic level?

The fundamental origin of magnetism lies in the behaviour of electrons within atoms. Magnetism is caused by two specific electron motions:

  • Orbital Motion: The movement of electrons in their orbit around the atom's nucleus creates a tiny magnetic field.
  • Electron Spin: Electrons also spin on their own axis, much like a spinning top, and this spin generates another, more significant magnetic field.
In most materials, these magnetic effects cancel each other out. However, in materials like iron, cobalt, and nickel, the electron spins do not completely cancel, causing the atoms to behave like tiny magnets and giving the material its magnetic properties.

5. How did the discovery of the link between electricity and magnetism change science?

The discovery of the link between electricity and magnetism, primarily by Hans Christian Oersted in 1820, was a pivotal moment in physics. Oersted noticed that an electric current in a wire could deflect a compass needle. This proved that the two forces were related. This led to the unified theory of electromagnetism, developed by James Clerk Maxwell, which established that electricity and magnetism are two facets of the same fundamental force. This breakthrough paved the way for technologies like the electric motor, generator, and all modern communications.

6. How is an electromagnet different from a permanent magnet like lodestone?

The key difference lies in the source and persistence of their magnetism. A permanent magnet, like lodestone, has an inherent magnetic field due to the fixed alignment of its atomic structure; its magnetism is always present. An electromagnet, on the other hand, is a temporary magnet. It is created by passing an electric current through a coil of wire, usually wrapped around an iron core. The magnetic field only exists when the current is flowing and disappears when the current is turned off.

7. What are some key milestones in the history of understanding magnetism?

The scientific understanding of magnetism evolved through several key discoveries:

  • c. 600 BC: Ancient Greeks discover lodestone (magnetite) and its attractive properties.
  • 1600: William Gilbert publishes "De Magnete," establishing a scientific basis for magnetism and identifying the Earth as a magnet.
  • 1820: Hans Christian Oersted discovers that an electric current produces a magnetic field, linking electricity and magnetism.
  • 1826: William Sturgeon invents the first electromagnet.
  • 1864: James Clerk Maxwell publishes equations that unify electricity and magnetism into a single theory of electromagnetism.

8. What are some important modern applications of magnetism?

Magnetism is essential to countless modern technologies. Some of the most important applications include:

  • Data Storage: Hard drives in computers and magnetic tapes use magnetism to store vast amounts of digital information.
  • Medical Imaging: Magnetic Resonance Imaging (MRI) machines use powerful superconducting magnets to create detailed images of the inside of the human body.
  • Electric Motors and Generators: The principle of electromagnetism is used to convert electrical energy into motion (motors) and motion into electrical energy (generators).
  • Speakers and Microphones: These devices use a combination of permanent magnets and electromagnets to convert electrical signals into sound waves and vice versa.