Classification of Materials
Not all materials react to magnets in the same way. Based on their behavior when brought near a magnet, materials are classified into two groups.
1. Magnetic Materials
These are materials that get attracted towards a magnet.
- Examples: Iron, Nickel, Cobalt.
- Common Objects: Iron nails, sewing needles, paper clips, keys.
2. Non-magnetic Materials
These are materials that are not attracted towards a magnet.
- Examples: Plastic, Wood, Rubber, Glass, Paper, Cloth, Aluminum, Copper.
- Common Objects: Pencils (wood), Erasers (rubber), Plastic bottles, Gold rings.
Warning
Note: Some metals like Gold, Silver, Aluminum, and Copper are non-magnetic. Only specific metals like Iron, Nickel, and Cobalt are magnetic.
Concept Map
Activity: Testing Materials
If you bring a magnet near various objects, you can predict and observe the results:
| Object | Material | Attracted? (Yes/No) |
|---|---|---|
| Iron Nail | Iron | Yes |
| Scale | Plastic | No |
| Shoe | Leather | No |
| Key | Steel (Iron alloy) | Yes |
| Coin (Modern) | Stainless Steel (Ferritic) | Yes (Some are magnetic) |
Magnetic Force Through Materials
Interestingly, magnetic force can pass through non-magnetic materials.
- If you place a paper clip in a glass of water and move a magnet on the outside of the glass, the clip will move.
- A magnet can influence iron filings through a sheet of paper or a plastic board.