Discovery of Magnets: Types & Uses

The discovery of the magnet is done by Magnes, an ancient Greek shepherd. He used to take his sheep and goats to the adjacent mountains to graze. He'd bring a stick with him to keep his herd in check.

• On one end of the stick, a small amount of iron was applied. 
• He was surprised to discover one day that he had violently wrenched the stick free from a boulder on the mountainside. 
• The stick seemed to be pulled to the rock. The iron tip of a shepherd's stick was drawn to the boulder like a magnet. 
• This is how natural magnets are thought to have been discovered.

Key Terms-: Electromagnet, Polarity, Bar Magnet, Field lines, Compass, Magnetic Moment, Bar Magnet

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History of Magnets

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Magnets have been around since the early 600s BC. "Magnesia" was the name of an island. Shepherds used to bring their cattle there. They had complained about their nail-studded shoes becoming caught on the ground. 

• Their rods with iron tips were also impacted. The presence of magnetic minerals in that location was the explanation. 
• The magnet was named after the island of "Magnesia."
• Greeks discovered that a piece of stone attracted the magnet as well. Magnetite was the mineral. 
• Natural magnets are these natural magnetite chunks. 
• The ancient Chinese literature also suggests that they were aware of the magnet's directional powers.
•  It was employed on ships as a navigation system. 
• Interestingly, the Chinese writings also mention a chariot on which a magnetic statue is placed. This chariot was employed to assault foes in the fog.

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Founder of Magnets

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Magnets make the globe go round, and stories of their discovery and application appear to come from all around the world.

Greece

Magnes, a Greek shepherd, is claimed to have been tending his sheep in Magnesia, a province of northern Greece, some 4,000 years ago. 

• He took a stride and discovered that the nails holding his shoe together and the metal tip of his staff were firmly attached to the rock he was standing on! 
• He began digging, intrigued, and unearthed the first recorded lodestone. 
• Lodestones were renamed "magnetite," most likely after Magnes or Magnesia.

Rome

During the early years of the Common Era, Pliny the Elder, a Roman naturalist, and writer, carried out notable scientific investigations on behalf of the Roman Emperor Vespasian. 

• He recorded an account of a hill composed of a stone with the ability to attract iron.
• Pliny associated the properties of this magnetite stone with magic, sparking a series of superstitious hypotheses about its characteristics. 
• These notions included the idea that ships which had vanished at sea might have been drawn to magnetic islands. 
• It's worth mentioning, though unrelated, that Pliny met his end during the eruption of Mount Vesuvius in Pompeii.

France

During the 13th century, Petrus Peregrinus, a scholar from France, authored one of the earliest written descriptions of the scientific attributes of magnets.

• In his writings, he included an illustration and discourse on the unfettered rotating compass needle
• Which played a crucial role in the development of the initial dry compass.
• According to legend, Peregrinus composed these texts while being involved in the Pope-approved crusade or assault on the Italian city of Lucera. 
• This certainly showcases his impressive ability to manage multiple tasks simultaneously!

Scandinavia

Due to a significant reservoir of lodestone found in Scandinavia and the lack of sufficient sunlight for ship navigation during winters, the Vikings were greatly motivated to apply the magnetic attributes of lodestone in a useful manner. 

• As far back as 1,000 B.C., it's believed that the Vikings employed a tool resembling a compass, crafted from lodestone and iron. 
• Historical accounts suggest that Viking seafarers employed a magnetized iron needle inserted into a straw and set afloat on the surface of a water-filled bowl 

China

It's possible that the Chinese crafted a mariner's compass before the Vikings did, employing a similar design. Around 800 A.D., the Chinese utilized a fragment of lodestone, set afloat on water, for navigation. 

• This technique preceded the Vikings' use of their own iteration of the compass by around 500 years. 
• The knowledge of the magnetic compass was eventually introduced to Italy by explorers like Marco Polo
• Thereby granting Europeans the capability to venture across oceans that the Vikings had already been traversing.

England

The individual who first succeeded in creating a magnet was, in fact, a physician named William Gilbert from Britain. 

• In the year 1600, he not only unveiled that the Earth possessed magnetic qualities but also demonstrated that magnets could be crafted from iron. 
• Additionally, he revealed that the magnetic attributes of these magnets could be diminished through the application of heat to the iron.

Read More: Oxides of Nitrogen

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Types of Magnets

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Magnets are classified into three types: permanent magnets, temporary magnets, and electromagnets.

Permanent Magnets 

These are the magnets that retain their magnetic properties after being magnetized. They do not require an external source of magnetism. 

• Permanent magnets are now constructed using alloys. 
• Samarium-cobalt-magnet, ceramics, aluminum-nickel-cobalt or alnicos, neodymium-iron-boron, and so on are some frequent examples. 
• Rare earth minerals are also utilized to create permanent magnets, which are referred to as rare earth magnets. 
• One such example is a neodymium-iron-boron magnet.

Permanent Magnet

Temporary Magnets

Some materials are easily magnetized. Even when exposed to a weak field, they become magnetized, but as soon as the field is removed, they lose their magnetic property. 

• These materials are referred to as temporary magnets. 
• Soft iron alloys and iron-nickel alloy mixtures are examples of such magnets. 
• These magnets are frequently employed in electric motors and electromagnets.

Temporary Magnet

Electromagnets

An electric current is utilized in this type of magnet. An electric current is passed through a wire that has been wrapped around a metal core. Orsted's research revealed that an electric current generates a magnetic field. 

• The strength of a magnetic field can be adjusted by varying the current strength and the number of coils in the wire.
• Electromagnets generate a powerful magnetic field. 
• However, the magnetic field persists as long as there is a current in the electromagnet. 
• Electromagnets are utilized in computers, television sets, electric motors, and other electronic devices.

Electromagnet

Read More: Inductance formula

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Uses of Magnets

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• Magnets have applications in practically every branch of science and technology. Some applications are listed below in summary form -
• Hard discs are used in computers to store data using magnets.
• Used in televisions, speakers, and radios.
• Magnets are employed in the construction of motors and generators.
• Magnets are used in the medical field for MRI scans, ventilators, blood separators, and other purposes.
• Magnetism is used to store data in various strip card machines, including as ATM cards.

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Things To Remember

• Magnets produce magnetic fields, with north and south poles.
• Lodestone, a natural magnet, was used for navigation by ancient Greeks.
• Chinese compasses in the 4th century BCE relied on magnetism.
• Oersted's 1820 discovery linked electricity and magnetism.
• Ampère and Faraday contributed to electromagnetism's development.
• The Industrial Revolution saw magnet integration in machinery.
• Modern uses include motors, MRI machines, and electronic devices.
• Earth's magnetic field results from its molten iron core's movement.

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Previous Year Questions

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