The Water Cycle: The Hydrologic Cycle

Water moves continuously in a circulation on the Earth’s surface. In general, there are over 70% of the surface of the Earth is covered by ocean. Singh and Singh (2001) defined that “water is a dynamic natural resource and continuously circulates between atmospheres, hydrosphere, lithosphere, and exosphere, and this unending circulation is referred to as the water cycle or hydrologic cycle” (p. 1). Water cycle is endless process through four main steps which are evaporation, condensation; infiltration and run off surface then water return to ocean (refer to Figure 1 in Appendix 1). Firstly, hydrological cycle begins with evaporation. In evaporation, the sun plays an important role to provide light energy and heat energy on the Earth’s surface. Heat energy supplied on the surface of water bodies especially ocean, river, lakes, ponds, and groundwater to change the water from liquid state to water vapor in gaseous state to facilitate the water vapors is transported into atmosphere. Most of the evaporated water is from the ocean. According to McKinney, Schoch and Yonavjak (2007), there are 425000 〖km〗^3 per year of the evaporated water that present in the atmosphere mostly from the ocean. Since the ocean is large water bodies, the water molecules of

By the way, condensation is the opposite of the evaporation. In condensation, the water vapor in gaseous form is changed back to liquid water. The evaporated water vapors in the atmosphere are gathered together to form cloud in the atmosphere. Clouds are the important component at the in the condensation process of the hydrologic cycle because the precipitation that occurs after the formation of cloud at the atmosphere. The low temperature of the atmosphere slow down the motion of water molecules, thus, it reduce the energy to lead the water molecules are holding together again in liquid form, eventually the water present as droplet (Nebel & Wright,