1. Fill a bucket with water.
2. Take a bottle with a narrow mouth and immerse it in the bucket till it fills with water.
3. During the time the bottle is filling with water bubbles of air come out of the glass.
4. This air is earlier filled in the glass. So the glass is not empty but full of air.
5. Any bottle, glass or any other container that appears empty is actually full of air.
6. Nothing can be added to it unless the air inside is removed.
7. It is only when some air is removed that something else can enter.
8. Air occupies the space around us.
