READ: Conduction, Convection, and Radiation

Summary

• Conduction is the transfer of thermal energy between particles of matter that are touching. Thermal energy is always transferred from particles of warmer matter to particles of cooler matter.
• When particles of warmer matter collide with particles of cooler matter, they transfer some of their thermal energy to the cooler particles.
• Convection is the transfer of thermal energy by particles moving through a fluid. Thermal energy is always transferred from an area with a higher temperature to an area with a lower temperature.
• Moving particles transfer thermal energy through a fluid by forming convection currents.
• Convection currents move thermal energy through many fluids, including molten rock inside Earth, water in the oceans, and air in the atmosphere.
• Thermal radiation is the transfer of thermal energy by waves that can travel through air or even through empty space. This is how thermal energy from a fire is transferred to your hands and how thermal energy from the sun is transferred to Earth.
• Everything radiates thermal energy, even objects that aren’t very warm.

Vocabulary

• conduction: Transfer of thermal energy between particles of matter that are touching.
• convection: Transfer of thermal energy by particles moving through a fluid.
• convection current: Flow of particles in a fluid that occurs because of differences in temperature and density.
• thermal radiation: Transfer of thermal energy by waves that can travel through air or across space.