Water CycleBell 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
Permeable Layers
Impermeable Layer
UnsaturatedZone
Water Table
Solid Rock
UnconnectedPores
Air
Water
Saturated Zone
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
GroundwaterArtesian Well
Aquifer
ImpermeableRock
WellDry
WellAquifer
WaterTable
Aquifer
Spring
