Lec 2: means by which energy is transferred. Lec 3: energy flows in the earth system. Lec 4: energy flows in the earth system. Transfer of heat by collision of molecules (physical contact) This type of heat transfer between the atmosphere and earth"s surface is also known as sensible heat flux. Positive sensible heat flux is from earth"s surface to the atmosphere. Evaporation (requires energy therefore removes heat from the liquid) Latent heat flux is directly proportional to evaporation. Latent heat flux is positive when there is loss of water (evaporation) Transfer of heat from one place to another by the movement of fluids (water/air) Energy transferred by the mass motion of molecules. Movement of fluid caused by hotter (less dense) material to rise, and colder (denser material) to sink. What type of energy transfer occurs mainly in: Is an electromagnetic wave that moves through space: distinguished by their wavelength. Longer wavelength less energetic and vice versa.