the particle model

• matter is anything that has mass and occupies space
• matter is found in three different states: solid, liquid and gas
• solids

  • definite shape and volume
  • cannot flow
  • very strong forces of attraction
  • cannot be compressed
  • positions of particles cannot be changed
• liquids

  • indefinite shape
  • definite volume
  • strong forces of attraction
  • particles are able to move over each other
  • changes shape according to the container
  • cannot be compressed
  • can flow
• gases

  • indefinite shape and volume
  • very weak forces of attraction
  • free to move around in random directions
  • can be compressed
• The Particle Theory

  • all matter is made of tiny particles
  • particles are moving all the time
  • there are forces of attraction holding the particles together
  • forces of attraction vary in strength in the different states of matter
• Brownian Motion


  the movement of particles in random directions
• particles collide with each other and push each other around which cause brownian motion
• diffusion


  when particles of one substance spread out and mix with particles of another, the spreading of particles from a region of high concentration to a region of low concentration
• diffusion stops when it is evenly spread(when it reaches equilibrim)
• when the surrounding temperature is higher, the heat energy is converted into kinetic energy in the particles, causing them to move faster. Hence the rate of diffusion will increase
• air pressure

  the force of air particles hitting a surface
• greater volume of gas in an enclosed space will cause the air pressure to go up
• atmospheric pressure refers to the weight of the Earth's atmosphere pressing down on everything
• vacumns suck out particles and have no particles inside it