How do Magnets Work - PHYSICS!

James Lincoln

22 Nov 201204:24

Summary

TLDRThis video explores the mystery of magnetism, starting with the historical discovery of magnetic minerals in Magnesia, Greece. It explains how magnetized iron has aligned magnetic domains, which can be manipulated to create or destroy magnetism. The role of electrons' spin in magnetism is highlighted, with iron, nickel, and cobalt being unique due to their paired electrons with parallel spins. The video concludes by emphasizing the quantum mechanical phenomenon of electron spin alignment in everyday magnets.

Takeaways

🧲 Magnets are naturally occurring minerals found in Magnesia, Greece, that can attract or repel each other.
🔍 Unmagnetized iron is made up of randomly oriented tiny crystal magnets called domains.
📚 Magnetization aligns the domains in iron, creating a north and south side, thus making it a magnet.
🔊 The flipping of magnetic domains can be made audible through a coil of wire and a speaker.
🌐 The magnetism in metals like iron, cobalt, and nickel is related to electron movement.
🔬 Electrons have a property called spin, which, when aligned, contributes to the magnetic properties of certain elements.
📊 The alignment of electron spins in iron, nickel, and cobalt is due to an unusual pairing of valence electrons with parallel spins.
🔥 Heating can disrupt the magnetic domains in a magnet, causing the loss of magnetism.
🔋 A coil of wire with a looping current acts like a bar magnet, influencing the direction of compasses.
🧬 Magnetism is a quantum mechanical effect that is observable in everyday life, particularly in iron, nickel, and cobalt.

Q & A

What is the origin of the term 'magnet'?
-The term 'magnet' originates from the ancient Greek region of Magnesia, where naturally occurring minerals that attracted iron were found.
How are magnetic domains related to magnetism?
-Magnetic domains are tiny crystal magnets within unmagnetized iron metal that are randomly oriented. In magnetized iron, these domains align, giving the metal a north and south side, which allows it to become a magnet.
What happens to the magnetic domains during the magnetization process?
-During the magnetization process, the magnetic domains in iron flip their orientation, aligning in a specific direction, which results in the material becoming a magnet.
How can the flipping of magnetic domains be made audible?
-The flipping of magnetic domains can be made audible by placing a small piece of nickel inside a coil of wire and bringing a strong magnet close to it, causing any rapid changes in the magnetic field to sound on a speaker.
Which elements are known to be magnetic besides iron?
-Besides iron, cobalt and nickel are also magnetic elements, and their proximity on the periodic table indicates that magnetism is a result of electron behavior.
How does heating affect the magnetic domains in a magnet?
-Heating can destroy the alignment of magnetic domains in a magnet, causing the magnet to lose its magnetism.
What property of electrons is responsible for magnetism?
-Electron spin, the intrinsic angular momentum of electrons, is responsible for magnetism. The alignment of these electron spins results in the magnetic properties of certain materials like iron, nickel, and cobalt.
Why do iron, nickel, and cobalt exhibit magnetism?
-Iron, nickel, and cobalt exhibit magnetism because they have an unusual double veence (valence) electron configuration where their two valence electrons have parallel spins, which is a rare circumstance.
What was the outcome of the experiment conducted by Albert Einstein and vonder deas to test the cause of magnetism?
-The experiment conducted by Albert Einstein and vonder deas to test whether orbiting electrons caused magnetism resulted in negative findings, leading to further investigation and the later discovery of electron spin.
How do the magnetic properties of a bar magnet compare to a coil of wire with a looping current?
-A coil of wire with a looping current acts just like a bar magnet, causing compasses to align with the magnetic field created by the current, pointing out of North and into South.
What is the significance of quantum mechanical effects in everyday life as it relates to magnetism?
-Quantum mechanical effects, such as the alignment of electron spins, are significant in everyday life as they are the fundamental reason behind the existence of magnets, which have numerous applications in technology and industry.

Outlines

00:00

🧲 The Mystery of Magnets

Magnets have the ability to either attract or repel each other, but the reason behind this phenomenon remains unknown. The term 'magnet' originates from the ancient Greek region of Magnesia, where naturally occurring minerals that attracted iron were discovered. These minerals could either attract or repel one another, providing the basis for understanding magnetic properties.

🧑‍🔬 Magnetic Domains in Unmagnetized and Magnetized Iron

Iron in its unmagnetized form is made up of tiny magnetic crystals, known as domains, which are oriented in random directions. In a magnetized state, all the domains align in a single direction, creating a north and south pole. This alignment of domains transforms the material into a magnet. During magnetization, the domains flip, a process that can be detected audibly with the right equipment.

🎧 Audible Domain Flipping

In a demonstration, a piece of nickel placed inside a coil of wire is exposed to a strong magnet. The flipping of magnetic domains inside the nickel produces a sound, making the invisible process of magnetization audible. This experiment highlights how even a small metal object can be turned into a magnet and shows how heat can destroy the magnetic properties by disorganizing the domains.

🧲 The Magnetic Properties of Iron, Cobalt, and Nickel

In addition to iron, cobalt and nickel are also magnetic, a property that is due to their proximity on the periodic table. The magnetic behavior of these elements is a result of electron behavior, specifically the alignment of electron spins. Magnetic fields can be created not only by permanent magnets but also by electric currents, as seen with a coil of wire carrying current.

🌀 Electron Orbit and Spin in Magnetism

Early theories proposed that orbiting electrons caused magnetism, but experiments in 1915, including one by Albert Einstein, disproved this idea. It was later discovered that electron spin, not orbital motion, is responsible for magnetism. The alignment of electron spins within atoms, particularly in iron, nickel, and cobalt, generates their magnetic properties. These elements have a unique electron configuration where two valence electrons are paired with parallel spins, making them naturally magnetic.

🔍 The Quantum Mechanism Behind Magnets

In conclusion, magnetism arises from the alignment of electron spins in the microscopic domains of metals like iron, nickel, and cobalt. This quantum mechanical effect is due to the unusual pairing of valence electrons with parallel spins. This phenomenon occurs naturally in certain elements, making magnets an everyday example of quantum mechanics at work.

Mindmap

Keywords

💡Magnet

A magnet is an object that produces a magnetic field, which can attract or repel other objects. In the context of the video, magnets are naturally occurring minerals that were found to attract iron in the region of Magnesia, hence their name. The video explains that magnets have a north and south side, and it's the alignment of the magnetic domains within a magnet that gives it its properties. The script uses the example of a magnet to demonstrate how it can magnetize an iron paper clip.

💡Magnetic domains

Magnetic domains are small regions within a ferromagnetic material where the magnetic moments of atoms are aligned. The video script explains that unmagnetized iron metal is composed of these randomly oriented domains, but when magnetized, all the domains align, giving the metal its magnetic properties. This concept is central to understanding how magnets work and is illustrated by the audible flipping of domains when a magnet is brought close to a piece of nickel.

💡Magnetization

Magnetization is the process by which an object becomes magnetized. The video script describes this process as one where the magnetic domains within a material like iron align, creating a north and south pole. The example given is the magnetization of an iron paper clip by a magnet, demonstrating how the domains flip to align with the external magnetic field.

💡Electron spin

Electron spin is a fundamental property of electrons that contributes to their magnetic moment. The video explains that the alignment of electron spins within the atoms of certain materials, like iron, nickel, and cobalt, is what results in their magnetic properties. This is a quantum mechanical effect that is crucial for understanding the intrinsic magnetism of these elements.

💡Ferromagnetism

Ferromagnetism is the basic mechanism by which certain materials form permanent magnets. The video script mentions that all magnetism is caused by electrons, and it is the ferromagnetic materials like iron, cobalt, and nickel that exhibit this property due to their electron configuration. The video ties this concept to the everyday use of magnets.

💡Orbiting electrons

Orbiting electrons refer to the electrons that move around the nucleus of an atom. The video script suggests that the motion of these electrons might be the cause of magnetism, but an experiment by Albert Einstein and vonder deas showed that this was not the case. Instead, it is the spin of the electrons that is responsible for magnetism.

💡Parallel spins

Parallel spins describe a situation where two electrons have their spins aligned in the same direction. The video explains that this is a rare occurrence and is the reason why only certain elements like iron, nickel, and cobalt exhibit strong magnetic properties. This is because these elements have an unusual configuration where their valence electrons have parallel spins.

💡Magnetic field

A magnetic field is the region around a magnet or moving electric charges where the force of magnetism acts. The video script uses the example of a coil of wire with a current flowing through it to illustrate how it can act like a bar magnet, creating a magnetic field that affects compasses. This concept is fundamental to understanding how magnets interact with their environment.

💡Cobalt

Cobalt is a chemical element that, like iron and nickel, is magnetic. The video script mentions cobalt as one of the few elements that can be magnetized due to its electron configuration, which includes paired valence electrons with parallel spins. This property makes cobalt an important material in the creation of strong magnets.

💡Quantum mechanical effect

Quantum mechanical effects are phenomena that are explained by the principles of quantum mechanics. The video script refers to the alignment of electron spins within magnetic materials as a quantum mechanical effect, highlighting that the behavior of electrons at this scale is crucial for understanding the macroscopic properties of magnets.

💡Valence electrons

Valence electrons are the electrons in the outermost shell of an atom, which are involved in chemical bonding and other chemical properties. The video script explains that the magnetic properties of iron, nickel, and cobalt are due to a unique configuration of their valence electrons, where they have parallel spins, leading to the alignment necessary for magnetism.

Highlights

Magnets can either repel or attract another magnet, and the reason behind this phenomenon is explained in the video.

Natural magnets were named after the region of Magnesia in ancient Greece where they were first discovered.

Unmagnetized iron metal consists of randomly oriented tiny crystal magnets called domains.

Magnetization involves aligning the domains in iron, creating a north and south side.

The alignment of domains can be heard as they flip, demonstrated by a nickel piece inside a coil of wire.

A magnet can induce magnetism in an iron paper clip by aligning its magnetic domains.

Magnetism can be lost by heating, which destroys the alignment of magnetic domains.

Besides iron, cobalt and nickel are also magnetic materials.

Magnetism is a result of electron movement, as indicated by the proximity of magnetic elements on the periodic table.

A coil of wire with a looping current acts like a bar magnet, influencing compass directions.

Electrons orbiting iron atoms might be the cause of magnetism, as suggested by the alignment of their movement.

Albert Einstein and vonder deas' experiment in 1915 aimed to confirm the role of orbiting electrons in magnetism.

Electrons possess a property called spin, which was later discovered to contribute to magnetism.

The alignment of electron spins is responsible for the magnetic properties of iron, nickel, and cobalt.

Iron, nickel, and cobalt have an unusual double veence with paired electrons spinning in parallel, a rare occurrence.

Magnets are a collection of microscopic crystal domains with aligned electron spins, particularly in iron, nickel, and cobalt.

The quantum mechanical effect of aligned electron spins is evident in everyday life through magnetism.