5.15. Convection http://www.ck12.org
Q:During the day, in which direction is thermal energy of the air transferred? In which direction is it transferred
during the night?
A:During the day, thermal energy is transferred from the air over the land to the air over the water. During the night,
thermal energy is transferred in the opposite direction.
Summary
- 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.
Vocabulary
- 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.
Explore More
Watch the video at the following URL, and then answer the questions below. http://video.google.com/videoplay?do
cid=1902141755519014330#docid=7379647004466944857
- Describe what you observed in the video.
- Explain your observations.
- Predict what you would observe if the procedure in the video continued.
Review
- What is convection?
- Describe how convection occurs and why convection currents form.
- Add arrows representing convection currents to the room in theFigure5.32 to show how thermal energy
moves from the radiator to the rest of the room. Label areas of the room that are warm and cool.