Conduction, Convection and Radiation

• What happens to an object's thermal energy store when it is heated?

  Energy is transferred to its thermal energy store
• What are the three ways heat can be transferred?

  Conduction, convection, and radiation
• How is heat transferred in solids?

  By conduction
• How is heat transferred in fluids?

  By convection
• How is heat transferred through empty space?

  By radiation
• What is the key idea behind conduction?

  Vibrating particles transfer energy to neighbors
• What happens when one end of a metal is heated?

  Energy is transferred to the kinetic energy store
• Why does conduction occur mainly in solids?

  Particles are held closely together
• What is thermal conductivity?

  How well objects transfer energy by conduction
• Which materials have high thermal conductivity?

  Metals
• Why are plastics used as insulators?

  They have low thermal conductivity
• What is convection?

  Heat transfer mainly in fluids
• What happens to particles in fluids when heated?

  They gain kinetic energy and move faster
• What occurs in a convection current?

  Hot particles rise, cool particles sink
• How does a blanket reduce convection?

  It stops the free flow of fluids
• What do conduction and convection have in common?

  Both involve particles gaining kinetic energy
• How is heat transferred through a vacuum?

  By radiation
• What type of waves carry energy during radiation?

  Infrared waves
• What happens to objects regarding radiation?

  They constantly absorb and emit radiation
• How does temperature affect radiation emission?

  Hotter objects emit more radiation
• Why does it feel hot to put your hand over a barbecue?

  Hot metal emits infrared radiation
• What is the electromagnetic spectrum?

  A range of all types of electromagnetic radiation
• What are the processes of heat transfer?

  • Conduction: Energy transfer through particle collisions
  • Convection: Energy transfer in fluids through movement
  • Radiation: Energy transfer through infrared waves
• How do conduction and convection differ in heat transfer?

  • Conduction: Energy transferred between particles
  • Convection: Particles themselves move to transfer energy
• What is the cycle of a convection current in a heated fluid?

  1. Particles near heat gain energy and rise
  2. Cooler particles sink to take their place
  3. Cycle repeats as long as fluid is heated