Electricity and magnetism are often taught as separate subjects in school, yet they are deeply interconnected. In fact, they are two sides of the same coin, linked through fundamental physical laws that govern how the universe works. Magnetism may first strike us as something simple—like a bar magnet sticking to a refrigerator—but its reach extends far beyond the ordinary. From guiding compasses across oceans centuries ago, to driving the motors that keep modern industries running, magnetism plays an essential role in science and technology.
Even more fascinating is the way magnetism and electricity influence one another. A moving electric charge generates a magnetic field, while a changing magnetic field can produce electricity. This profound relationship, called electromagnetism, underpins some of the most important inventions of the modern age, including electric motors, generators, transformers, and magnetic resonance imaging (MRI).
In this article, we will explore the foundations of magnetism, the discovery of its link with electricity, and the ways in which electromagnetism powers the technology of today
The Nature of Magnetism
Magnetism is a force arising from the movement of electric charges. It is most commonly observed in certain materials—iron, cobalt, and nickel—that have unique atomic structures enabling them to become magnetized.
Every magnet has two distinct ends called poles: a north pole and a south pole. Like poles repel each other, while opposite poles attract. This interaction is not limited to the visible ends of a magnet; it exists throughout the magnetic field surrounding the object. If you were to sprinkle iron filings around a bar magnet, you would see them arrange themselves into curved lines extending from the north pole to the south pole. These invisible lines represent the magnetic field, which describes both the strength and the direction of the magnetic influence.
On a deeper level, magnetism originates from the behavior of electrons inside atoms. Electrons not only orbit the nucleus, but also spin on their own axes. Both their motion and spin produce tiny magnetic fields. In most materials, these microscopic fields cancel one another out. But in ferromagnetic substances such as iron, many of these atomic fields align, creating a strong, collective magnetic effect.
The Earth as a Magnet
Magnetism is not confined to small objects we hold in our hands. In fact, our entire planet is magnetic. The Earth has a magnetic field that resembles that of a giant bar magnet tilted slightly off from the planet’s rotational axis. This magnetic field extends far into space, shielding Earth from harmful solar radiation and helping to shape phenomena like the auroras seen near the poles.
Compasses work because of this planetary magnetism. The needle of a compass, itself a small magnet, aligns with Earth’s magnetic field, always pointing toward magnetic north. This simple property has guided explorers, sailors, and travelers for centuries, making Earth’s magnetism not just a scientific curiosity but also a tool of immense practical importance.
Interestingly, Earth’s magnetic field is not static. It slowly shifts and even reverses over geological timescales. At various points in Earth’s history, the magnetic north and south poles have switched places, a phenomenon recorded in the alignment of magnetic minerals within ancient rocks.
Magnetic Materials and Their Properties
Not every material responds to a magnetic field in the same way. While iron, nickel, and cobalt are strongly attracted to magnets, other substances display only weak magnetic behavior or none at all.
Materials that are strongly attracted to magnets and capable of being permanently magnetized are called ferromagnetic materials. When exposed to a strong magnetic field, the microscopic magnetic regions inside them, known as domains, align in the same direction. Once aligned, these domains can remain in place, effectively turning the material into a magnet itself.
This property is why pieces of iron can become magnetized when placed near a strong magnet, and why electromagnets often use iron cores to amplify their strength.
Electricity Creates Magnetism: The Birth of Electromagnetism
One of the most revolutionary discoveries in physics came in the early 19th century, when scientists realized that electricity and magnetism are directly connected. In 1820, Hans Christian Ørsted observed that a compass needle moved when placed near a current-carrying wire. This simple but groundbreaking experiment revealed that moving electric charges generate magnetic fields.
Whenever an electric current flows through a wire, a magnetic field forms around it. The field is circular, wrapping around the wire like invisible rings. The direction of this field depends on the direction of the current. While the field produced by a straight wire is relatively weak, its strength can be dramatically increased by shaping the wire into a coil. Each loop of the coil reinforces the others, creating a concentrated field at the center.
When an iron core is placed inside the coil, the magnetic effect is amplified even further. This combination produces an electromagnet, a magnet whose strength can be controlled by adjusting the electric current. Unlike permanent magnets, electromagnets can be switched on and off, making them extraordinarily useful in technology.
Electromagnets appear in countless applications: cranes that lift heavy scrap metal in junkyards, doorbells that chime when a button is pressed, and advanced machines like MRI scanners that peer inside the human body without surgery. Their versatility stems from the simple fact that electricity can create magnetism, and humans have learned to harness this principle with remarkable creativity.
Magnetism Creates Electricity: Induction and Generators
The relationship between electricity and magnetism works in both directions. In the 1830s, Michael Faraday and Joseph Henry discovered that a changing magnetic field could generate an electric current in a wire. This process is known as electromagnetic induction.
When a magnet is moved near a coil of wire, the magnetic field through the coil changes. This change induces a flow of electrons—an electric current—through the wire. The effect is stronger if the magnet moves quickly or if the coil contains many turns of wire.
This principle is the foundation of many technologies. Generators, for example, convert mechanical energy into electrical energy by rotating coils within magnetic fields. Every power plant in the world, whether fueled by coal, gas, nuclear reactions, or renewable sources like wind and water, relies on this principle to generate the electricity that lights our homes and powers our devices.
Conversely, electric motors apply the same principle in reverse: they use electricity to create motion. In a motor, electric current flows through coils of wire placed in a magnetic field. The interaction between the current and the field produces a force that causes the coils—and the motor shaft attached to them—to rotate. This conversion of electrical energy into mechanical energy is what powers countless machines, from household appliances to industrial equipment.
Transformers, another crucial technology, also rely on electromagnetic induction. By using magnetic fields to transfer energy between coils, transformers can change the voltage of electricity. This makes it possible to transmit electrical power over long distances efficiently before stepping it down to safe levels for home use. Without transformers, modern power grids would be impossible.
Electromagnetism in Everyday Life
Although electromagnetism may sound abstract, it is woven into the fabric of daily life. Every time you turn on a fan, hear music from a speaker, or ride a subway train, you are experiencing electromagnetism in action.
Electric motors, found in everything from washing machines to electric cars, rely on electromagnetic forces to turn electrical energy into motion.
Generators, on the other hand, perform the opposite conversion, ensuring that the motion of turbines—driven by steam, flowing water, or wind—becomes the electricity we depend on.
Medical technology also takes advantage of electromagnetism. MRI machines use powerful electromagnets to generate detailed images of the human body, allowing doctors to diagnose conditions without invasive procedures. Even everyday conveniences like doorbells and headphones operate on the principle that electricity and magnetism are intertwined.
Some of the most futuristic technologies also rely heavily on electromagnetism. Maglev trains, which float above tracks and glide at incredible speeds, are lifted and propelled by magnetic forces. These trains reduce friction almost entirely, enabling smooth and efficient travel.
The truth is, without electromagnetism, the modern world would look entirely different. It is not just another branch of physics—it is the engine behind progress.
Why This Matters
Understanding magnetism and electromagnetism is more than an academic exercise. These forces underpin nearly every technology we use, from the smallest household gadget to the global electrical grid. Recognizing how they work helps us appreciate the ingenuity behind human inventions and the deep connections between natural forces.
At the same time, this knowledge provides practical benefits. It explains why motors and generators function, how transformers make our power systems possible, and why electromagnets are essential in industries ranging from healthcare to transportation. On a personal level, it allows us to look at the world with new eyes, seeing the hidden interplay of electricity and magnetism behind everyday conveniences.
Conclusion
Magnetism and electricity, once thought to be separate phenomena, are in fact inseparable. Together, they form the foundation of electromagnetism, a force that drives both nature and technology. From the Earth’s magnetic field that guides compasses, to the motors that run our appliances, to the power plants that keep cities illuminated, electromagnetism is everywhere.
By exploring how magnets work, how electric currents generate magnetic fields, and how changing magnetic fields can create electricity, we uncover one of the most profound relationships in physics. More than just theory, electromagnetism explains the functioning of countless devices that define the modern world.
If you are curious to deepen your understanding of this fascinating subject, we invite you to visit Mentivia.com and explore our course on Electricity and Magnetism. With step-by-step lessons designed for clarity and engagement, you’ll gain the knowledge to truly appreciate the forces shaping our lives.