science assessment term 2

• Particle models of matter

  Explain conduction, convection and radiation as methods of heat transfer
• States of matter


  • Solid - fixed shape, very close together, vibrate in fixed position
  • Liquid - no regular arrangement, close, roll over each other
  • Gas - no regular arrangement, move very fast in all directions, far apart
• Phase changes


  1. Solid - liquid = melting

  2. Liquid - gas = evaporation

  3. Gas - liquid = condensation

  4. Liquid - solid = freezing
• Conduction


  Heat transfer through direct contact, occurs most in solids
• Convection


  Heat is transferred by the movement of heated fluids/liquids
• Radiation


  Transfer of heat through electromagnetic waves
• Waves are carriers of energy
• Waves carry energy
• Waves carrying energy


  • Sound waves from clapping hands
• Longitudinal waves


  Waves where the direction of the waves are parallel to the direction of the vibration of the particles
• Transverse waves


  Waves where the direction of the waves are perpendicular to the direction of the vibrations of the particles
• Common wave features


  • Wavelength
  • Amplitude
  • Period
  • Frequency
  • Crest
  • Trough
  • Compression
  • Refraction
• Wavelength


  The distance between the top of one wave to the top of the next
• Frequency


  The number of crests that pass a point in one second
• Amplitude


  The height of the wave from the resting point
• Compression


  When the particles in the air are close together
• Refraction


  The bending of light
• Trough


  The lowest point of each wave
• Crest


  The highest point of each wave
• Period


  The amount of time it takes for the wave to complete one wavelength
• Rarefaction

  When the particles in the air are spread out
• High-energy waves have shorter wavelengths and low-energy waves have longer ones
• Sound waves


  The movement of energy through a medium by longitudinal mechanical waves of compressions and rarefactions
• Transmission of sound in different mediums

  1. Air: Sound travels slower because the particles are far apart

  2. Water: Sound travels faster because the particles are closer

  3. Solids: Sound travels the fastest because the particles are packed very closely together
• Frequency and pitch


  The higher the pitch the greater the frequency
• Amplitude and volume


  • Higher amplitude means louder sound
  • Smaller amplitude means quieter sound
• Electromagnetic spectrum


  • Radio waves
  • Microwaves
  • Infrared radiation
  • Ultraviolet radiation
  • X rays
  • Gamma rays
• Light


  The movement of energy through a vacuum by electromagnetic transverse waves
• Optical properties


  • Transparent
  • Translucent
  • Opaque
• Transparent


  Allows all or most light to travel through
• Translucent


  Allows some light to pass through
• Opaque


  Blocks all light passing through
• Law of reflection


  The angle of incidence is always equal to the angle of reflection
• Everyday examples of reflection


  • Twinkling stars
  • Rainbow
  • Camera lens
• Plane mirror


  The incident angle always is the same as the angle of reflection
• Concave mirror


  Light rays that strike a concave mirror converge (come together) to a focal point after reflection
• Convex mirror


  Light rays that strike a convex mirror reflect outward (diverging)
• Refraction


  The bending of light or sound as it passes through glass, walls etc
• White light is made up of R, O, Y, G, B, I, V
• Heat transfer


  The movement of heat from one object to another object