Page 97 - Science Class 6 Times Publication

Gas

Gases have neither xed shape not  xed volume.
Molecules in gases are loosely arranged. Intermolecular
force is the least but the intermolecular space is the
highest. Due to this, molecules in gases can spread
freely. Gases can be compressed in a tyre, football,
balloon, etc.

Gas molecules
Activity 9.3

To show that a liquid has xed volume but a gas does not have

Materials required: Syringe, water, etc.

Procedure

1. Take a syringe without needle.
2. Pull the piston to the maximum level.

3. Block the hole of the syringe with a thumb, then push the
piston. What happens?
Syringe tube

Water Piston

Again ll the syringe with water and repeat the above activity. What

happens?

Observation: You can compress the air but you cannot compress the
water.

Conclusion: A gas has no xed volume but a liquid has xed volume.
Change in state of matter

Matters can be changed from one state to another by heating or
cooling. This process is called change in state of matter.

Times' Crucial Science and Environment 93 Book 6