particles

• Matter


  What things and substances are made of
• States of matter


  • Solid
  • Liquid
  • Gas
• Solids


  • Particles are close together by strong forces of attraction
  • Can vibrate in their fixed positions back and forth
  • Do not flow or change shape
  • Fixed volume and shape
  • Cannot be compressed
• Liquids

  • Can change shape and flow
  • Fixed volume and cannot be easily compressed
  • Particles are close together by fairly strong forces of attraction
  • Can move past each other
• Gases

  • Particles are far apart from each other, the forces of attraction between the particles are weak
  • Free to move about in all directions
  • No fixed shape or volume
  • Can easily be compressed
• Particle theory

  • All matter is made of tiny particles
  • Particles are moving all the time
  • There are forces of attraction holding the particles together
  • The forces vary in strength in the different states of matter
• Brownian motion

  1. Air particles hit specks of smoke

  2. If many particles hit one side of a smoke speck, they push the speck in that direction

  3. The air particles are moving about randomly and so the direction in which the smoke speck is pushed will change all the time
• Diffusion


  • Process where particles move from a region of higher concentration to a region where they're lower concentration
  • Diffusion occurs when particles spread and are free to move
  • Heat energy will convert to kinetic energy, particles move faster; rate of diffusion increases
• Air particles


  • Forces of particles hitting on a surface
  • Refers to the volume of air in a particular environment
• Greater volume of air

  Higher pressure
• Atmospheric pressure


  Weight of the earth's atmosphere pressing down on everything
• Vacuum

  Does not contain anything, not even air
• Tyre gets bigger


  More air particles inside are pushing out
• Air is removed from a can

  The can is pushed in by the air particles hitting the outside of the can
• the brownian motion supports the particle theory because many air particles hit the speck of smoke, pushing it in different directions
• air pressure is caused by the gas particles hitting surfaces
• air pressure can be increased by putting more air into a tyre
• particles in solids vibrate in one place
• particles in liquids are close together but can still move past each other
• a gas can be compressed because the particles are far apart
• brownian motion

  observed when pollen grains are floating on water
• gasses spread out and mix together more quickly than liquids because gas particles are further apart
• d drop of coloured liquid when put in cold water without stirring, will dissolve and mix with water as particles in liquids are always moving
• pressure in a container with gas is caused by particles bumping into the walls
• as a driver pumps up the tyres of the car, the pressure increases as there are more gas particles hitting on the surfaces of the tyre
• diffusion does not happen in solids because solid particles are closely packed with strong forces and cannot move freely
• diffusion happens faster in a gas, gas particles move faster than particles in a liquid
• theory: a hypothesis that explains how or why something happens
• hypothesis: an idea about how something works that can be tested using experiments