How is Rain Made? As clouds are formed by condensed water, the individual water droplets collide and combine to make bigger water droplets. When water droplets are too heavy to float in the air, it falls as rain. Atmosphere Condensation Evaporation Water Vapor Ocean Vocabulary * Atmosphere - the layer of gases surrounding a planet * Water Vapor - the gas phase of water * Photosynthesis - the process in which plants use sunlight, water and air to create its food * Groundwater Storage and Groundwater Flow water stored underneath the surface of the earth * Condensation - the process of water vapor in the air turning into liquid water * Evaporation - the process of liquid water becoming water vapor * Transpiration - evaporation of water from plant leaves during photosynthesis * Seepage - movement of water through small openings of material into surface or subsurface water * Infiltration - flow of water from the surface into the ground * Precipitation - water is released from clouds into the form of rain, freezing rain, sleet, snow or hail * Snow Melt Runoff Surface water produced by melting snow * Surface Runoff - is the flow of water "running off" the land surface from precipitation into streams, lakes and oceans