We all know, that the entire universe is made up of matter. Matter is made up of tiny particles,  which are continuously in motion. These particles, are separated by spaces between them. Matter, can be defined as anything that occupies space, and has mass and volume. Matter is everywhere, and its states are represented by its nature or appearance. Based on the packing of the particles, making up the matter and the forces existing between them, it can occur in three states namely solid, liquid and gas. 

For instance, if we take the same substance to exist in three different forms, then water exists in its solid form as ice, liquid form as water and in gaseous form as water vapour. 

On the contrary, let us consider a situation. where three diferent substances represent, different states of matter. You eat a spoon full of rice representing solid, you drink juice representing liquid, and breath in the fresh air in the form of gas.

NGSS- 

HS-PS1-3

HS-PS1-5.

PS1.A

ETS1.C

Common Core Standards Connections

­WHST.9­12.7

­MP.4

­MP.2

Solids, liquids and gases, vary in their properties,  with respect to shape, volume, compressibility, rigidity, occupying space completely.

*Solids have a fixed shape, fixed volume, difficult to compress, rigid, and do not occupy the entire space available. 

*Liquids do not have fixed shape but they have fixed volume, they are incompressible, fluids that have the ability to flow, and do not occupy the entire space available.

*Gases do not have a fixed shape and volume, they are compressible and exist as fluids that have ability to flow and occupy the entire space available for them.

Properties of matter can be classified based on distance between the particles, force of attraction between the particles and the kinetic energy of the particles.

a. Particles are tightly packed in a solid as the distance between the particles is very less. This makes the force of attraction between them very strong. Though the particles in a solid are tightly packed, they are continuously moving as vibrations at the mean positions. The movement exhibited by the particles is very less and hence the kinetic energy of the particles is very small.

b. Particles are loosely packed in a liquid as the distance between the particles is more. This makes the force of attraction between them weak and the particles exhibit motion with more kinetic energy.

c. Particles are very loosely packed in a gas as the distance between the particles is very large. This makes the force of attraction between the particles very negligible. These particles are always in motion with maximum kinetic energy.