Particulate Nature of Matter

• Brownian Motion.

  • Random movement of microscopic particles suspended in a liquid or a gas.
  • Smoke particles move constantly in different directions.
  • Smoke particle is bombarded by air & moves about randomly.
• Solid.

  • Has a definite volume.
  • Has a definite shape.
  • Cannot be compressed.
• Liquid.

  • Has a definite volume.
  • Has no definite shape.
  • Cannot be compressed.
• Gas.

  • Has no definite volume
  • Has no definite shape.
  • Can be compressed.
• Solid.

  The particles in a solid are very closely packed in an orderly manner. They vibrate about their fixed positions. There is very little space between the particles for them to move closer together. The particles are held together by very strong forces of attraction.
• Liquid.

  The particles in a liquid are closely packed in a disorderly manner. They move randomly and slide past one another. The particles are closely packed but are a little further apart than in a solid. There is little space between the particles for them to move closer together.
• Gas.

  The particles in a gas are far apart and arranged in a disorderly manner. They move randomly and quickly. There is a lot of space between the particles for them to move closer together. The particles are held together by weak forces of attraction.
• The number and size of particles in a substance do not change during Expansion and Contraction. Thus, there is conservation of mass.
• Diffusion.

  Net movement of particles from a region of higher concentration to a region of lower concentration.