Transcript Water Cycle
Water Cycle Bell Work: Where does the water cycle get its energy from? What is the water cycle? • The water cycle describes the existence and movement of water on, in, and above the Earth. • Water is always in motion • Water is always changing states – Liquid – Solid – gas Hydrologic Cycle • The water cycle can also be called the Hydrologic Cycle…WHY? • Since the water cycle is truly a "cycle," there is no beginning or end. • Water can change states among liquid, vapor, and ice at various places in the water cycle • These processes have been happening over millions of years. • The water in the apple you ate yesterday may have fallen as rain half-way around the world last year or could have been used 100 million years ago by Mama Dinosaur to give her baby a bath. Components of the Water Cycle • • • • • • • • • • • • • • • • Water storage in oceans Evaporation Sublimation Evaporation Water in the atmosphere Condensation Precipitation Water storage in ice and snow Snowmelt runoff to streams Surface runoff Stream flow Freshwater storage Infiltration Ground-water storage Ground-water discharge Springs Water storage • 96.5% of the water on earth is in the oceans • 3.5% of the water on earth is fresh • 90% of the evaporated water contained in the water cycle came from the ocean • Ice caps and glaciers Evaporation • Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. • The water vapor, or steam, leaves the river, lake or ocean and goes into the air. • 90% comes from oceans, seas, lakes and rivers • 10% comes from plants: transpiration • Humidity • Evaporation removes heat from the environment: HOW?? • Once evaporated, a water molecule spend about 10 days in the air. Sublimation • Sublimation: The change of snow or ice to water vapor without melting • Solid gas • High amounts of energy is needed….Where would this energy come from??? • South side of Mt. Everest: – Low temperatures – Strong winds – Intense sunlight – Low air pressure Transpiration • Transpiration is the process by which plants lose water out of their leaves. • Transpiration gives evaporation a bit of a hand in getting the water vapor back up into the air • Moisture is carried through plants from roots to small pores on the underside of the leaves, where it changes to vapor and is released to the atmosphere. • A large oak tree can transpire 40,000 gallons of water a year. • Factors that effect Transpiration: – Temperature – Relative humidity – Wind and air movement – Soil-moisture availability – Types of plants Water in the atmosphere • The atmosphere always contains water • Tiny water particles are too small to see UNLESS…. • Clouds • Superhighway used to move water around the globe Condensation • Condensation: Water vapor in the air gets cold and changes back into liquid, forming clouds. • Responsible for the formation of CLOUDS • Vapor liquid • Condensation is the opposite of evaporation • Fog • Moisture on your windows or drink – Water vapor in the warm air, turns back into liquid when it touches the cold glass Precipitation • Precipitation: Occurs when so much water has condensed that the air cannot hold it anymore. • The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow • Millions of cloud droplets are required to make a single raindrop Precipitation Rates Vary by location Surface Runoff • Surface Runoff: Occurs as precipitation travels over the soil surface to the nearest stream channel. • Run over the soil and collect in the oceans, lakes or rivers where the cycle starts • Ground saturation • Flash flood • Deposition can happen during this time….What was that?? • Dangerous time for pollution to occur A watershed is an area of land where all of the water that falls in it and drains off of it goes into the same place. Groundwater • A portion of the water that falls as precipitation can infiltrate (seeps into) the subsurface soil and rock. • Used by plants and burrowing animals • Keeps soil cool during the summer Groundwater Air Water Unsaturated Zone Permeable Layers Water Table Saturated Zone Solid Rock Unconnected Pores Impermeable Layer Water Table • The top of the surface where ground water occurs is called the water table Aquifer • An underground layer of water-bearing porous stone, earth, or gravel Groundwater Spring Artesian Well Aquifer Aquifer Water Table Aquifer Impermeable Rock Dry Well Well