Theory:

Take a moment to look at your surroundings. You see a variety of things with different shapes, sizes and textures. The water we drink, the food we eat, the cloths we wear, and the air we breath everyday; each of these things have their own mass and volume.
 
For example, a building or house is constructed with the help of bricks, stones and other solid materials.
 
And, the water we drink, the lake, and the sea, etc. are in the liquid form. Then, the air we breathe and the gases in our atmosphere are in a gaseous stage.
 
Therefore, generally, we can classify the matters into three types.
  • Solid state
  • Liquid state
  • Gaseous state
States of  matter.png
 
In upcoming exercises, we shall learn about these three states of a matter in greater details.
Reference:
https://www.shutterstock.com/image-vector/changing-state-matter-solid-liquid-gas-1279186903