As you go about your daily routine, you likely encounter and utilize technologies that incorporate magnets in some form. Magnets play an integral role in many of the appliances and devices you rely on each day. The applications of magnets in daily life are numerous and impactful. Magnets are essential components in everything from keeping your refrigerator door sealed shut to powering the speakers that play your favorite music. They are equally critical in powering the technologies that have become ubiquitous, like the smartphone you check constantly and the laptop you use for both work and leisure. Magnets may operate behind the scenes, but their contributions to daily life are significant and worth recognizing. This article explores some of the many practical applications of magnets that you experience routinely.
Magnets in Refrigerators and Freezers
Magnets play an integral role in the functioning of refrigerators and freezers. The magnets are used to seal the refrigerator and freezer doors, creating an airtight seal that helps keep cold air in and warm air out.The most common types of magnets used in refrigerators are flexible rubber magnets and magnetic strips. The rubber magnets are placed around the rim of the refrigerator door, where they hold the door tightly against the refrigerator body. Magnetic strips may also be used, with one strip on the door and one on the frame of the refrigerator to hold the door closed through magnetic attraction.Some refrigerators also use electromagnets, or magnets that can be turned on and off using electricity. These are often used in combination with magnetic door seals. When the refrigerator door is closed, the electromagnet is activated to provide a strong seal. When the door is opened, the electromagnet is deactivated so the door can be opened easily. Electromagnets allow for an airtight seal without requiring a strong magnet that would make the door difficult to open.In addition to sealing the doors, some refrigerators also use magnets in their compressors and pumps. The magnets are essential for the proper circulation of refrigerants like freon that are used to cool the refrigerator. By controlling the flow of refrigerants through magnetic fields, the refrigerator can efficiently cool its contents.
Magnets in Loudspeakers and Headphones
Magnets are essential components in loudspeakers and headphones. They are responsible for converting the electrical signal into the mechanical energy required to produce sound.In loudspeakers and headphones, magnets are used in combination with coils of wire to create an electromagnet. When an electric current flows through the coil, it creates a magnetic field that interacts with the static magnetic field of the permanent magnet. This interaction results in a force that moves the coil and attached diaphragm, which in turn vibrates the air to create sound waves.
The strength of the permanent magnet directly impacts the efficiency and performance of the loudspeaker or headphones. More powerful magnets allow for stronger magnetic fields, higher forces on the coil, and greater diaphragm excursion. This results in louder, clearer audio with a wider frequency range. Many high-fidelity loudspeaker and headphone designs utilize rare earth magnets, like neodymium iron boron (NdFeB) magnets, to achieve the best possible performance.
In some designs, the permanent magnet is stationary while the coil moves. In other designs, the coil remains fixed while the magnet and attached diaphragm move. The specific operating principle depends on the construction and intended use of the loudspeaker or headphones. Some use an overhung voice coil in a fixed magnetic gap, some use a diaphragm with a voice coil attached that moves a magnet, while others use a moving iron armature design. However, they all rely on the interaction of magnetic fields to produce the forces required for sound creation and fidelity.
Magnets in Hard Drives and Storage Devices
Magnets play an integral role in the functioning of hard drives and other storage devices. Storage devices like hard disk drives (HDDs), solid-state drives (SSDs), and flash drives all rely on magnets to store and read digital data.HDDs contain spinning magnetic platters that hold data. As the platters spin, a magnetic read/write head moves across the surface to access the data. The magnetic fields of the platters and read/write heads enable the storage and retrieval of data. More specifically, the magnetic polarities of the platter surface represent 1s and 0s - the binary code that all digital data is composed of. By changing the polarities, data can be written to the hard drive. Reading the polarities allows the data to be accessed and retrieved.SSDs and flash drives use magnetic storage in the form of floating gate transistors. These transistors have a layer of polysilicon that holds an electrical charge, which represents data. The charge is trapped in place by a layer of silicon oxide and silicon nitride. To change or access the data, magnetic fields are used to tunnel electrons through these layers. This allows the data to be rewritten or read as needed.
As storage technologies have advanced, magnets have enabled greater storage densities, faster read/write speeds, and more reliability. However, all storage devices are still limited by the strength and stability of magnetic fields, as well as the precision with which those fields can be manipulated. Continued improvements in magnetic data storage will drive further progress in computing, smartphones, and many other technologies that have become deeply embedded in daily life. Overall, magnets play an instrumental and often unheralded role in enabling modern digital storage and access to information.
Magnets in Magnetic Resonance Imaging (MRI)
How MRI Magnets Work
The magnets in MRI scanners are supercooled electromagnets that generate a strong, uniform magnetic field around the patient. Most MRI magnets utilize coils of superconducting wire through which flows an electric current. The coils are immersed in liquid helium to cool them to nearly -270°C, at which temperature they become highly conductive and generate an intense magnetic field. The strength of the magnetic field is measured in tesla - most MRI scanners operate at 1.5 to 3.0 tesla. The higher the Tesla rating, the more detailed the images can be.
The magnetic field causes the protons in the patient's body to align in the same direction. Short pulses of radio frequency waves are then directed at the patient to alter the alignment of the protons systematically. When the radio frequency pulses are turned off, the protons realign with the magnetic field and release electromagnetic signals that are measured by the MRI scanner. These signals are used to construct digital images that can reveal minute details about the tissues and structures inside the body. By altering the timing and intensity of the radio frequency pulses, MRI scanners can scan different "slices" of the body and in different orientations to build up a comprehensive, 3D view.
MRI technology has revolutionized medical imaging and diagnosis. The detailed images it produces allow physicians to identify abnormalities, diagnose medical conditions, and monitor the progression of diseases. MRI scans are often used to examine the brain, spinal cord, heart, and other soft tissues in the body.
Magnets in Motors and Generators
Magnets are essential components in electric motors and generators. Their ability to produce magnetic fields that interact with electric currents and magnetic materials allows them to convert electrical energy into mechanical energy and vice versa.
Motors contain magnets that spin a shaft when an electric current is applied, powering innumerable devices and machines. As the magnetic field generated by the motor's magnets interacts with the electric current, it creates a force that rotates the shaft. The strength and polarity of the magnets, as well as the amount of electric current, determine the speed and power of the motor.
Generators employ the opposite effect, using mechanical energy to spin magnets within a coil of wire and produce electricity. The moving magnetic field induces an electric current in the wire. The faster the magnets spin, the more electric current is generated. Nearly all commercially produced electricity comes from large generators containing powerful magnets and coils.
On a smaller scale, magnets are found in sensors, switches, and actuators in a wide range of equipment. Their magnetic fields detect and move ferrous metals with precision and efficiency. For example, magnets in switches open and close circuits, while those in sensors detect the position and motion of components. Magnetic actuators directly move and control mechanisms in devices like hard disk drives, valves, and locks.
Magnets in Magnetic Tools
Magnets are instrumental components in many tools we use daily. Their ability to attract and repel metals allows for innovative designs and functions not possible with other materials.
Magnetic Pickup Tools
● Have you ever dropped a small metal object like a screw, nail, or key into an awkward space? Magnetic pickup tools, like magnetic wands or pick up sticks, help retrieve these items. At the end of an extendable stick is a powerful magnet that can grab and lift the metal object. For tight spaces where fingers can't reach, these pickup tools are extremely useful.
Stud Finders
● Hanging heavy decor or installing shelving often requires locating wall studs. Stud finders use magnets to sense the presence of nails or screws in studs behind the wall. As you slide the stud finder across the wall, its magnets detect the magnetic field of the metal fasteners, indicating there is a stud. Stud finders pinpoint the stud's center and edges to ensure you install attachments securely.
Magnetic Wristbands
● For those doing mechanical work or construction, dropping nails, screws, nuts or washers can be an annoyance. Magnetic wristbands provide a simple solution. The wristband contains magnets that keep the metal items attached until needed. Simply drop the item onto the wristband and it will stick in place. When ready to use, grab it off the wristband. No more chasing parts that fall or roll away.
Magnetic Levels
● Levels with magnetic strips allow you to attach them temporarily to metal surfaces. The magnets keep the level in place so you have both hands free to install shelves, artwork, or other items that require precision. Once level, you simply lift the level off the surface to remove it, leaving no damage or residue. For tasks where an extra set of hands would be useful, magnetic levels are a convenient solution.
Magnets in Magnetic Levitation and Maglev Trains
How Maglev Trains Work
Maglev trains employ superconducting magnets to levitate the train above the track. As the train moves, the magnetic fields propel it forward at high speeds. The lack of friction means maglev trains can reach speeds of up to 375 miles per hour.
Magnetic Levitation
● Powerful superconducting electromagnets installed on the underside of the train lift it and levitate it about an inch above the guideway. The magnetic fields repel the train from the guideway, causing levitation due to the Meissner effect. The train is kept stabilized laterally within the guideway walls.
Linear Propulsion
● Once levitated, the train moves forward through a linear motor. The motor uses changing magnetic fields to propel the train along the guideway. As the magnetic fields alternate in polarity, they push and pull the train forward in a smooth gliding motion. The linear motor requires no moving parts and creates propulsion through electromagnetic forces.
Benefits of Maglev Technology
Some benefits of maglev technology include:
● Environmentally friendly - No emissions, little noise pollution.
● High speeds - Can reach over 300 miles per hour due to lack of friction.
● Low maintenance - No moving parts means less need for repairs or servicing.
● Smooth ride - Passengers experience a smooth, vibration-free ride due to magnetic levitation and propulsion.
● Reduced costs - Lower infrastructure and operating costs compared to high-speed rail.
Magnets in Magnetic Separation Processes
Magnets play an important role in magnetic separation processes, which are used for sorting and purifying materials. As materials move past the magnet, the magnetic components are attracted to the magnet, while the non-magnetic materials continue unaffected.
Magnetic Separation of Metals
● Metals that contain iron, nickel, and cobalt are magnetic, while most other metals are non-magnetic. When a mixture of magnetic and non-magnetic metals goes through a magnetic separator, the magnetic metals cling to the magnet, leaving the non-magnetic metals behind. Recycling centers use this method to sort ferrous metals like iron and steel from non-ferrous metals such as aluminum.
Purification of Minerals and Compounds
● Magnetic separation is also useful for extracting valuable minerals from ores and compounds. Certain minerals, like hematite (iron oxide), are magnetic, while most minerals are non-magnetic. When crushed ore goes through a magnetic separator, the hematite sticks to the magnet, separating from the non-magnetic minerals. This allows the hematite to be collected for further processing into iron and steel. Similar processes separate other magnetic minerals like magnetite.
Removal of Metallic Contaminants
● Another key use of magnetic separation is to remove metallic contaminants from various materials. Plastic, wood, grain, and other materials can get small pieces of iron or steel lodged in them during processing and handling. Passing these materials over a magnetic drum or plate pulls out these contaminants, leaving the materials clean and suitable for their intended uses.
Applications of Magnets in Construction
Magnets have many useful applications in the construction industry. Their ability to lift and move heavy objects without direct contact makes them ideal for manipulating steel beams, girders, and other metal building materials.
Shuttering Magnet Formwork System Precast Concrete Magnets
Also known as formwork magnets, Precast concrete magnets are a practical and high-tech way to secure formwork to the casting bed. Because rare earth neodymium magnets have a stronger pulling force than other magnetic elements, they are used in their construction. The magnetic component of the shutter magnets is coated with steel to distribute the magnetic flux and enhance the contact area.
Housings that are encircled by a neodymium magnet can shield them from harm, and the steel can be utilized to fasten a housing to the magnet.
Chamfer Magnets
Create a 45-degree beveled edge, known as a chamfer, along the edges of precast concrete panels. They are placed along the edges of the formwork before the concrete is poured. Once the concrete has hardened, the chamfer magnets are removed, leaving behind the characteristic angled edge. Chamfer magnets produce a more esthetically-pleasing panel joint than a simple butt joint. They cost slightly more, but many contractors find they are worth the investment.
Concrete Chamfer For Precast
One of the most practical and popular accessories in the precast concrete sector is magnetic chamfers. We presently provide steel magnetic chamfer strips, rubber magnetic chamfer strips, polyurethane chamfer strips, and PVC chamfer strips among other varieties of chamfering strips. For swiftly and accurately producing chamfers, beveled edges, drip molds, fake seams, notches, and exposes on the corners and faces of concrete wall panels as well as the Corner of various templates, magnetic chamfers are frequently used to secure steel formwork surfaces and steel workbenches. Prevent concrete from spilling out of the opening between the side formwork and the precast concrete pouring platform.
Lifting and Moving Metal Materials
● Powerful crane magnets are used on construction sites to lift steel beams, pipes, and sheets. The magnets securely grasp the metal objects so they can be transported around the site and put into place for assembly. Permanent magnets as well as electromagnets are used for this purpose. Electromagnets offer the advantage of being able to turn the magnetic field on and off, releasing the objects when needed.
Separating Metals
● Magnets are also used to separate metal objects from waste and recycling streams. As conveyor belts move mixed waste past powerful magnets, ferromagnetic metals like steel, iron, and nickel are pulled out of the stream, separating them for recycling. Non-ferrous metals like aluminum and copper are left to continue down the belt for further sorting. Separating metals in this way allows for more efficient recycling.
Inspection
● Some construction sites use magnetic inspection to check for flaws or imperfections in steel structures like beams. The magnetic flux emitted by the magnets interacts with the steel, and any changes in the magnetic field can indicate issues like cracks, voids, or other defects in the metal. Magnetic particle inspection is one method, using fine ferromagnetic particles that gather around flaws in the presence of a magnetic field. Any areas where the particles cluster indicate problems that need to be addressed.
Securing Structures
● Permanent magnets are sometimes embedded in concrete foundations and beams to secure steel structures in place. The magnetic force between the magnets and the steel structure creates a strong bond, helping to stabilize and anchor the structure. This application is often used when welding steel directly to concrete is not possible. The magnets provide a simple, chemical-free way to firmly attach the two materials.
Applications of Magnets in Daily Life FAQs
Magnets are used in many common appliances and technologies that you likely encounter every day. Below are some of the most frequently asked questions about how magnets are applied in daily life.
How are magnets used in refrigerators and freezers?
● Magnets are a key component in refrigerators and freezers. The doors of these appliances contain magnetic seals and gaskets that create an airtight seal when the door is closed. Magnets embedded in the door frames attract the metal in the seals and gaskets, holding the doors shut securely. This allows for efficient temperature regulation and prevents cold air from escaping.
How do magnets work in motors and generators?
● Many motors and generators rely on magnets to function. Magnets provide the magnetic fields required to spin motor rotors and generate electric currents. As magnets spin around conductive coils, they induce a magnetic force that pushes and pulls on electrons in the metal, creating an electric current. This is how magnets are essential for producing power in generators and enabling motorized equipment to operate.
How are magnets utilized in medical technologies?
● Magnets have important applications in the medical field. Magnetic resonance imaging (MRI) machines use powerful magnets to scan the body and generate detailed images of internal organs and tissues. Magnetoencephalography (MEG) scanners use magnetometers to map brain activity by detecting minute magnetic fields produced by electrical activity in the brain. Magnetotherapy or magnetic field therapy uses magnetic fields to allegedly treat pain and improve health, though there is limited evidence to support many of the health claims.
How do magnets work in televisions, computer monitors, and electronic devices?
● Many technologies like televisions, computer monitors, hard drives, and speakers contain magnets. In TVs and monitors, magnets are used to guide electron beams to light up pixels on the screen and produce images. Hard drives have magnets that generate magnetic fields to read and write data to the drive. Speakers contain magnets that work with electric coils to convert electronic signals into mechanical energy, which creates sound waves. Magnets are truly essential for powering many of the electronics we depend on every day.
FAQ
Can Magnets Play a Role in Water Softening?
● Yes, magnets are sometimes used in household water softening systems as they may help reduce the buildup of calcium and magnesium ions in pipes and appliances. While the effectiveness of magnetic water softening is still debated, this technology has gained some attention for its potential to reduce scale formation, especially in residential water systems. By minimizing mineral deposits, magnetic water softeners may help maintain plumbing efficiency and prolong the lifespan of water-using appliances.