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Metals
Electrical conductivity of solid materials
Solid materials can be classified into two main categories:
- Electrical conductors that can be crossed by an electric current.
- Insulators that don't conduct electric current.
To determine whether a material is conductive, a test of conductivity can be performed using the following circuit:
The principle of this test is simple:
- If the bulb lights, it indicates that the electric current flows then the material is conductive.
- If the bulb doesn't light, it indicates the electric current doesn't flow so the material is insulative.
Test results:
| Tested materias | Test results: |
| Iron | Conductor |
| Zinc | Conductor |
| Aluminium | Conductor |
| Copper | Conductor |
| Copper sulfate powder | Insulator |
| Salt powder | Insulator |
| Wood | Insulator |
| Plastic | Insulator |
This test permits to show that only metals are conductors and most other solid materials are insulators.
This characteristic can be explained by their microscopic properties
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