What do magnets attract?
If you’ve pinned a bottle opener to the body of a fridge, stacked thumbtacks together, or plugged an external hard drive into a computer, then you know what a magnet is and what magnets often attract. Beyond the science of how they work, magnets are simply devices capable of attracting other devices, particularly metals.
Substances that are receptive to a magnet’s attraction are magnetic materials, and substances that repel this attraction are non-magnetic. Magnetic fields, produced by magnets, and electric fields, produced by electric charges, work together to make electromagnetic forces. If you want to learn more about the mechanisms of magnets and what they attract, continue reading this article.
What are magnets?
Magnets are objects made from elements that produce magnetic fields. They are composed of north and south poles; the fields’ lines of forces enter the magnets through the north pole and exit through the south pole. These lines of forces trigger attraction to metals such as iron, cobalt, and nickel.
The strength of a magnet varies with its component material. Neodymium magnets, an alloy of neodymium – a rare-earth metal – with iron and boron, are perhaps the strongest magnet known today. Alnico magnets combine aluminum, nickel, and cobalt, which, as the name implies, are a strong grade, though not as strong as neodymium magnets.
Manufacturers also make simple magnets from iron oxide fixed in a ceramic composite. These are ceramic magnets, and they fit for household uses. The magnet on your refrigerator is possibly a ceramic magnet. Recently, manufacturers have experimented with samarium, another rare earth metal family element. Samarium, when mixed with cobalt, becomes a samarium cobalt magnet.
Magnets attract other elements due to the presence of unpaired odd electrons. Elements are made up of atoms with electrons in their orbit. These electrons are paired to keep the atom stable; orbits often attain a stable octet structure when all the electrons in individual shells within the orbit have been paired. Electrons circle an atom’s orbit and, as it does, create magnetic lines. These lines are canceled out as electrons move in opposite directions.
But what happens if an electron becomes unpaired? Iron has a configuration of twenty-six (26) electrons but, in many cases, exists as a charged particle. It could lose up to three electrons when charged, leaving free, unpaired electrons. The electrons create magnetic lines that accumulate with subsequent random rotations. These lines exert magnetic influences on the metal, turning the atom into a magnet. When multiple atoms within an element become magnetic, the whole magnet produces magnetic lines of forces with exit and entrance poles.
Note that metals that attract other materials have long been considered “magnets.” The description was historically used for stones that pick up a ferrous material. Travelers who used compasses also found that a magnet would always indicate the north-south direction, regardless of its needle’s roaming.
Temporary magnets cannot generate a magnetic field but can induce a field when brought in contact with high-grade magnets. The induced magnetic field shows the same intensity as a permanent magnet. However, the magnetic field is lost when the object is withdrawn from the strong magnet. Examples of temporary magnets include paper clips. If you bring an iron nail wound around a coil close to a strong magnet the nail becomes charged and can attract metals of a small radius nearby due to the temporary magnetic field it has acquired; the nail would stop attracting metals once it is removed from the strong magnet.
Permanent magnets retain a magnetic field for extensive periods. Permanent magnets hardly lose their magnetism except in very rare cases. Most permanent magnets have a shelf life of up to 100 years and can reject the influences of a demagnetizing object. Permanent magnets emit a strong magnetic field at a low mass. There are different categories of permanent magnets, including neodymium magnets, iron magnets, and alnico magnets.
What objects do magnets attract?
Magnets attract a variety of objects, especially metals. The science behind the attraction of magnets to specific materials can be explained using the reactions between unpaired electrons in the orbit of an atom that makes up the said material. However, magnets do not attract all kinds of materials. Materials that are attracted by magnets are called ferromagnetic materials. In these materials, The unpaired electrons in permanent magnets form strong bonds with the free electrons in the materials or metals. The strength of the Bond formed determines the strength or weakness of the magnetic attraction. For instance, metals such as lead and tungsten also form magnetic bonds, but the Bond pales when compared to the Bond between a neodymium magnet and a bar of iron.
Unsurprisingly, magnets attract a mixture of two or more ferromagnetic metals. Alnico, an aluminum, nickel, and cobalt alloy, can be attracted by other magnets. The neodymium alloy is used to make some of the strongest magnets known and can be attracted by magnets made of aluminum or iron alloys. Alloys of metals combined with elements such as carbon also behave as ferromagnetic objects. However, not all alloys are strongly ferromagnetic, so the elements combining must be equally ferromagnetic.
Some minerals can attract magnets. Hematite, or iron oxide, has weak magnetic tendencies due to the impurities caused by the oxygen atoms in its makeup. A strange magnetic substance is black sand, a mixture of partly magnetic substances. This attraction is relevant in mining gold, as magnets are used to pull the impure magnetic sand away from the gold. Lodestone, another magnetic material, is made of magnetite, which is likewise magnetic.
Random Household Items
Apart from the common magnetic items in the house, magnets can also attract any substance containing iron. This includes liquids and cereals. Many kinds of cereal are (expectedly) iron-fortified, so don’t be surprised to see the grains jumping at a piece of a strong magnet dangling above them.
Grades of Magnets
Magnet grades suggest the strength of magnets. For many manufacturers, grades help to set prices as magnets are sent for shipping. Should grades be a criterion for the kind of magnet you purchase? Possibly. You may not always need the strongest available magnet, so settling for strong magnets becomes unhelpful in specific situations.
Neodymium magnets are measured using the mega-gaussian-oersted (MGOe), and the values range from 30 MGOe to 55 MGOe. An N42 magnet will not be as strong as an N52 magnet, though the performance of the N42 magnet can be elevated by altering its pole size or, in some magnets with thin poles, the temperature of the magnet.
Samarium Cobalt magnets have MGOe ranging between 16 MGOe and 32 MGOe. The common Samarium Cobalt magnets are graded 16, 18, 20, 22,…, 32. As with Neodymium magnets, higher-ranked magnets are stronger than lower-ranked magnets under controlled environmental circumstances.
Neodymium magnets are also graded based on their responsiveness to heat and elevated temperatures. These grades do not correspond to strength. An N40SH magnet will outlast an N48 magnet under predetermined conditions.
A Neodymium material graded as N42 shows that the magnet can operate at temperatures below 80oC. An N45M magnet can be used at a maximum operating temperature of 100oC. Other known temperature grades are:
- “H,” for up to 120C
- “SH” up to 150C
- “UH” up to 180C
- “EH” up to 200C, and
- “TH” up to 220C
Facts about magnets
Magnets are popular in industries that use electromagnetic waves to generate power. Magnets are also found in many devices in many homes. Other random facts about magnets are:
- Cow magnets, special alnico magnets, are used to preserve a cow’s health. While grazing, cows may ingest metal debris, causing the condition known as hardware disease. To fix this, a piece of a magnet is introduced to the cow’s stomach, administered using a balling gun. The magnet keeps the metal object in the stomach and prevents it from piercing other vital organs.
- Some magnets can be demagnetized. Temporary magnets easily lose their magnetic intensity. However, permanent magnets can also be demagnetized if the magnets are corroded or if blunt force is applied against the magnets. Demagnetization isn’t always recommended, except in urgent cases.
- Magnets are tooted as beneficial for medicinal purposes. Magnet therapy is a hypothetical treatment of conditions including arthritis and body pain using static magnets. Though this may be helpful, magnet therapy isn’t a proven approach to healing.
It is great to understand how magnets work and what they attract. This knowledge also guides how we use magnets at home. If you want a new magnet or magnetic toy, confer with magnet experts before placing your order.
At ROBO Magnetic, we are excited to help individuals get the best deal for their money. Got a question? Leave a message, and we’ll be with you in no time.