“Those change in which only the physical properties of the substance change but no new substance are formed are called physical changes.”
- In the physical change substance do not change their identity but there occur only a change in some of their physical properties such as physical state shape and size.
- There fore after the physical change has occurred the substance can be easily convert back to their original form by some physical process.
- Thus the physical change are temporary and hence can be easily reversed.
Example of physical changes:
- Melting of ice to form water and freeze of water to form ice.
- When ice in contact with heat or energy it convert into water.
- Though both ice and water look different they are made up of water molecule.
- In other word no new substance is form during melting of ice.
Boiling of water to form steam and condensation of steam to form water.
- When water is heated to form steam.
- Though both ice and water look different they are made up of water molecule.
- In other word no new substance is form during boiling of water to form steam.
Preparing a Solution:
- Suppose we dissolved some common salt inwater.
- The common salt disappeared to form slat solution.
- Thus a change has taken place during formation of salt solution
Breaking a glass tumbler:
- When a glass tumbler beak , it form number of small pieces , but each smallpiece number of glass particles.
- Thus during breaking of glass substance no new substance are formed but shape , size of the substance are change.
- Thus breaking of glass tumbler is physical change.
Question Answer:
1) What is Physical change?
Answer: Those change in which only the physical properties of the substance change but no new substance are formed are called physical changes.”
2) Write properties of physical change?
Answer: • In the physical change substance do not change their identity but there occur only a change in some of their physical properties such as physical state shape and size.
- There fore after the physical change has occurred the substance can be easily convert back to their original form by some physical process.
- Thus the physical change are temporary and hence can be easily reversed.
3) Give example of physical change?
Answer: 1) Melting of ice to form water and freeze of water to form ice.
- When ice in contact with heat or energy it convert into water.
- Though both ice and water look different they are made up of water molecule.
- In other word no new substance is form during melting of ice.
2) Breaking a glass tumbler:
- When a glass tumbler beak , it form number of small pieces , but each small piece number of glass particles.
- Thus during breaking of glass substance no new substance are formed but shape , size of the substance are change.
Thus breaking of glass tumbler is physical change.