Which of the following is a process in which hot, less dense materials rise upward and are replaced by colder, more dense materials?

The correct answer is Convection.

Key Points

• Convection is a mode of heat transfer by the actual motion of matter.
• Convection is a process in which hot, less dense materials rise upward and are replaced by colder, more dense materials.
• Convection is possible only in fluids.
• Convection can be either be natural or forced.
• Gravity plays a major role in natural convection.
• Material is forced to move by a pump or by some other physical means in forced convection.
• Forced-air heating systems in the home, the human circulatory system are the common examples of forced convection.

Additional Information

• The three distinct modes of heat transfer are:
  1. Conduction.
  2. Convection.
  3. Radiation.
• The process of heat transfer without any medium is called radiation.
• Conduction is the process of heat transfer between two adjacent parts of a body due to their temperature difference.
• Condensation is the process where water vapor becomes liquid.