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?

  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 be transferred without particles?

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

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

  All objects absorb and emit radiation constantly
• Why does a hot object feel hot when near it?

  It emits infrared radiation absorbed by skin
• What is the relationship between temperature and radiation emission?

  Hotter objects emit more radiation
• What are the processes of heat transfer?

  • Conduction: Energy transfer through particle collisions in solids
  • Convection: Energy transfer through fluid movement in liquids and gases
  • Radiation: Energy transfer through infrared waves in a vacuum
• What are the differences between conduction and convection?

  • Conduction: Energy transferred between particles; occurs in solids
  • Convection: Particles themselves move; occurs in fluids
• What is the cycle of convection currents in fluids?

  1. Heated particles gain energy and rise
  2. Cooler particles sink to take their place
  3. Cycle repeats as long as heating continues
• What is the electromagnetic spectrum's relation to infrared radiation?

  • Infrared radiation is part of the electromagnetic spectrum
  • It is emitted by all objects based on their temperature