Answer :
Classifying materials into hard and soft categories depends on their physical properties like hardness and flexibility. Here's how you can classify the given materials:
- **Hard Materials**: Diamond and Brick
- **Soft Materials**: Clay and Foam
To determine if a material is lustrous or non-lustrous, you can perform a simple test using silver and plastic plates.
1. Take the material you want to test and observe its reflection on both the silver plate and the plastic plate.
2. If the material shows a clear and bright reflection on the silver plate, it is lustrous. If the reflection is dull or blurry on the plastic plate, the material is non-lustrous.
This test helps you differentiate between materials based on their ability to reflect light, indicating whether they are lustrous (shiny) or non-lustrous.
