1) Take a syringe .
2) First add chalk powder in the syringe. Try to push the piston of the syringe. It will not be pushed as particles of solids are closely packed.
3) Then put water in the syringe, the piston will be pushed little as particles of the liquid has some space between the particles.
4) Finally put nothing in the syringe as gas will be present . The syringe will be pushed maximum as gases are highly compressible in nature.