We will discuss about materials, water and air. Our world is made up of different kinds of materials. These are rocks, stones, soil, sand, iron, wood, water and air.
Things that we use in our daily life are made up of different kinds of materials.
All materials are grouped under solids, liquids and gases. All materials have certain common features. Materials occupy space.
When we keep our books in a particular place and our schoolbag in a particular place we observed they occupy space. We can’t keep anything else in the space which is already occupied by our books and schoolbag; we need to move these to make space.
(i) Suppose if one car is parked in the garage we can’t park another car in the same place in the garage because solid objects occupy space.
(ii) Fill a tumbler with water to the brim. What happens when we pour more water into the tumbler then the excess water flows out. From this simple example we can understand why a river causes floods in the monsoon because the river is full of water. During the monsoons, when more water comes into the same river, it overflows onto the surrounding land area causing floods because liquid occupies space.
(iii) Take a balloon without air it is limp and flat. Blow air into it then we see air has occupied or filled the space within the balloon. If we fill more and more air in that balloon, it will burst. The balloon bursts because there is no more space in the balloon to hold more air. Air gas occupies space.
Fill a vessel with water. Turn an empty tumbler upside down. Press it down straight into the water. Water cannot enter the tumbler because it contains air. Tilt the tumbler slightly then we see air bubbles coming out of the tumbler. Now, water enters the tumbler.
What common property do we find in each of these materials (materials, water and air)?
We find that materials of all kinds occupy space.