Conduction, Convection & 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?

  In the form of 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 can heat energy be transferred without particles?

  Through radiation in a vacuum
• What type of waves carry energy during radiation?

  Infrared waves
• What happens to radiation absorption and emission in objects?

  All objects absorb and emit radiation constantly
• 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 related to in this context?

  It includes infrared radiation
• What are the processes of heat transfer?

  • Conduction: Energy transfer through particle collisions
  • Convection: Energy transfer through fluid movement
  • Radiation: Energy transfer through infrared waves
• Compare conduction and convection in terms of particle movement.

  • Conduction: Energy transferred between particles
  • Convection: Particles themselves move to transfer energy
• What are the characteristics of convection currents?

  • Hot particles rise
  • Cool particles sink
  • Cycle continues as long as heating occurs
• What is the role of thermal conductivity in materials?

  • High thermal conductivity: Metals transfer heat quickly
  • Low thermal conductivity: Plastics act as insulators
• How does temperature influence radiation emission?

  • Higher temperature: More radiation emitted
  • All objects emit and absorb radiation constantly