A rare earth magnet, known for its exceptional strength, will primarily pick up materials that are ferromagnetic. These materials are strongly attracted to magnets and can even become magnetized themselves.
Understanding Magnetism: What Attracts a Rare Earth Magnet?
Rare earth magnets, such as those made from neodymium (NdFeB) or samarium cobalt (SmCo), are among the strongest permanent magnets available. Their impressive magnetic force stems from their unique atomic structure, which allows their electron spins to align easily, creating a powerful magnetic field.
The key property that determines whether an object will be picked up by a magnet is ferromagnetism. Only ferromagnetic materials are strongly attracted to magnets. Other types of materials, such as paramagnetic and diamagnetic materials, interact very weakly with magnets and will not be picked up under normal circumstances.
Key Ferromagnetic Materials Attracted by Rare Earth Magnets
Rare earth magnets are designed to attract and hold materials that exhibit strong magnetic properties. The most common and notable materials they will pick up include:
- Iron (Fe): This is the most common ferromagnetic material and the primary component of steel. Examples include nails, screws, paper clips, car bodies, and many tools.
- Nickel (Ni): Often found in alloys, nickel is also ferromagnetic. Some coins, specific stainless steels, and certain types of batteries may contain nickel.
- Cobalt (Co): While less common in everyday items, cobalt is a powerful ferromagnetic metal used in various alloys, including some high-strength magnets and cutting tools.
- Some Rare Earth Metals: Specific rare earth elements, beyond those used to make the magnet, can also be ferromagnetic, especially at certain temperatures. Examples include gadolinium and dysprosium.
- Alloys of Ferromagnetic Metals: Many alloys combine iron, nickel, or cobalt with other elements to enhance their properties, while retaining their magnetic attraction.
- Steel: An alloy of iron and carbon, steel is widely used in construction, appliances, and countless manufactured goods. All forms of steel that contain significant amounts of iron (like carbon steel, stainless steel with high iron content, etc.) will be picked up.
- Alnico: An alloy primarily composed of Aluminum (Al), Nickel (Ni), and Cobalt (Co), Alnico is itself a strong permanent magnet material and will interact with other magnets.
- Naturally Occurring Minerals: Certain minerals found in nature are inherently ferromagnetic.
- Lodestone (Magnetite): A naturally magnetized mineral form of iron oxide, lodestone is one of the earliest discovered magnetic materials and is strongly attracted to magnets.
Common Items Rare Earth Magnets Will Pick Up
Given the prevalence of ferromagnetic materials in our daily lives, rare earth magnets can pick up a wide array of common objects:
- Hardware: Nails, screws, bolts, washers, nuts, staples, paper clips.
- Tools: Wrenches, screwdrivers, hammers (parts containing steel or iron).
- Household Items: Refrigerator doors, steel appliances, some kitchen utensils (e.g., stainless steel flatware, but not all stainless steels are magnetic), metal bottle caps.
- Coins: Some coins, particularly older ones or those containing nickel, will be attracted. However, many modern coins made of copper, brass, or aluminum alloys are not magnetic.
- Electronics: Certain internal components of electronics, especially speakers (which contain magnets) or parts made of steel.
- Scrap Metal: Many types of scrap metal from construction or manufacturing will be picked up, particularly those primarily composed of iron or steel.
What Rare Earth Magnets Typically Don't Pick Up
While powerful, rare earth magnets only attract ferromagnetic materials. They will not pick up common non-ferromagnetic materials, including:
- Aluminum
- Copper
- Brass
- Gold
- Silver
- Lead
- Wood
- Plastic
- Glass
- Rubber
- Water
Understanding the distinction between ferromagnetic and non-ferromagnetic materials is key to predicting what a rare earth magnet will attract.
Ferromagnetic vs. Non-Ferromagnetic Examples
To illustrate, here's a quick comparison of common materials:
| Attracted (Ferromagnetic) | Not Attracted (Non-Ferromagnetic) |
|---|---|
| Iron (Nails, Cast Iron Pans) | Aluminum (Soda Cans, Foil) |
| Steel (Screws, Appliances) | Copper (Pennies, Wires) |
| Nickel (Some Coins, Alloys) | Brass (Keys, Ornaments) |
| Cobalt (Specialty Alloys) | Gold (Jewelry) |
| Lodestone (Natural Magnetite) | Silver (Jewelry, Cutlery) |
| Alnico (Magnet Alloys) | Wood |
| Some Rare Earth Metals (Gadolinium) | Plastic |
| Glass |
