Have you ever heard of Eddy currents? They may sound like the name of a band or a type of breakfast cereal, but they are actually an important scientific concept that can help us understand the world around us. Eddy currents are the swirling electrical currents that are induced in a conductor when exposed to a changing magnetic field, whoops! That may sound complicated, but don’t worry.
To understand eddy currents, we must first talk about magnets. Magnets have two poles, north and south, and have the ability to attract or repel other magnets or magnetic materials, for example, if you hold two magnets close to each other, you will notice that they stick together or separate depending on their poles. Now, imagine you have a metal plate, such as a sheet of aluminum or copper, and we put it between two magnets, as the magnets move towards and away from the metal plate, the magnetic field they create around them changes. This changing magnetic field induces a flow of electrical current in the metal plate, creating eddy currents.
Eddy currents can be seen in action in many real-world applications, one of the most common uses being in magnetic brakes, which are used on trains, roller coasters, and other vehicles to slow or stop them. In a magnetic brake, the brake pads are made of a conductive material, such as copper, and the braking force is created by eddy currents that are induced in the brake pads when exposed to a changing magnetic field; the stronger the magnetic field, the stronger the eddy currents and the greater the braking force.
So why should you care about eddy currents? Well, for one thing, they’re a great example of how science can help us understand and improve the world around us. By studying eddy currents, engineers and scientists can design more efficient brakes, better welding processes, and more effective metal detectors.
But eddy currents also have some practical applications in everyday life, for example, your smartphone or laptop probably has a fan to help keep it cool. The fan motor uses eddy currents to spin the fan blades, which helps dissipate heat and prevents the device from overheating. And if you’ve ever ridden a roller coaster or taken a train, you can thank eddy currents for helping keeping you safe and comfortable on your journey.