1. Chemical Changes

2. Physical Changes
Physical changes - involve the change of a state, shape or form of matter, but the composition of the substance remains the same.
Example: Water is composed of hydrogen atoms and oxygen atoms. Whether water is in its liquid form, solid form as ice or gas form as water vapour, its composition is still H2O.

3. Tearing of paper or the crushing of rocks
Tearing of paper or the crushing of rocks. There is no change in composition of the substance, but there is a change in the size of the substance.
Substances that are mixed together and can be separated by physical means undergo a physical change. Physical means of separation include processes such as distillation and filtration.

4. Chemical Changes on the other hand…
There are some very definite signs that a chemical change has taken place.
1. If the original composition of the compound cannot be retrieved.
2. If an explosion has occurred.
3. If heat or flames have been released.
4. If a gas has been released.
5. If the colour has changed.
6. If an odour has been released.
7. If a solid or precipitate has been formed.