How to classify materials based on nature?
| Hard materials | Soft materials |
| These materials cannot be compressed or scratched easily | These materials can be compressed or scratched easily |
| For example, Metals | For example, Wax |
How to classify materials based on solubility?
| Soluble materials | Insoluble materials |
| These materials completely dissolve in water | These substances do not mix with water and do not disappear even after stirring for a long time |
| For example, Salt | For example, Pebbles |
Classification based on Sinking or Floating in Water
If the object doesn’t dissolve in water then there can be two outcomes: the object can either sink or float. Thus, this parameter is for substances that are insoluble.
Substances made up of plastic, or any such lighter materials easily float on water. On the other hand, a few solid and heavy substances like the ones made up of metal cannot float. They are so heavy that they sink to the bottom of the container when added to the water.
Sinking and Floating