WaterWater

Chapter 17Chapter 17

The water cycleThe water cycle

• All of the water that is part of Earth is called the All of the water that is part of Earth is called the hydrosphere.hydrosphere.

• There is a constant cycle of water between the There is a constant cycle of water between the atmosphere and the hydrosphere that plays a big atmosphere and the hydrosphere that plays a big role in determining weather patterns and role in determining weather patterns and climates.climates.

• Bodies of water evaporate due to the suns energy Bodies of water evaporate due to the suns energy and enter the atmosphere as water vapor.and enter the atmosphere as water vapor.

• When the water vapor cools it returns to earth as When the water vapor cools it returns to earth as liquid in the form of rain or solid snow.liquid in the form of rain or solid snow.

• That cooling process of water vapor is called That cooling process of water vapor is called condensation.condensation.

The water cycleThe water cycle

• When condensation occurs very high When condensation occurs very high with in the atmosphere, clouds form.with in the atmosphere, clouds form.

• Clouds are made of tiny water Clouds are made of tiny water droplets that eventually collide with droplets that eventually collide with other tiny water droplets to form other tiny water droplets to form rain.rain.

• The rain that falls from clouds is The rain that falls from clouds is called precipitation. And completes called precipitation. And completes the water cycle.the water cycle.

Surface WaterSurface Water

• Some rain water soaks through the ground Some rain water soaks through the ground while some evaporates into gas. The rain while some evaporates into gas. The rain water that doesn’t do wither one of these, water that doesn’t do wither one of these, runs over the ground and ends up in lakes, runs over the ground and ends up in lakes, streams and oceans and is called run off.streams and oceans and is called run off.

• The amount of rain and how long it rains for The amount of rain and how long it rains for are two factors that affects run off.are two factors that affects run off.

• Light rain over a long period will have time Light rain over a long period will have time to soak into the ground, where as heavy to soak into the ground, where as heavy rain over a short period of time will not.rain over a short period of time will not.

• Another factor for the amount of run Another factor for the amount of run off is steepness or slope of the land, off is steepness or slope of the land, because gravity causes water to because gravity causes water to move down slopes more rapidly. move down slopes more rapidly.

• When water moves down a slope When water moves down a slope quickly, it does not have a chance to quickly, it does not have a chance to soak into the ground and vice versa.soak into the ground and vice versa.

• Vegetation increases the amount of Vegetation increases the amount of water soaked into the ground. The water soaked into the ground. The presence of plants, slows down water presence of plants, slows down water and allows it to be soaked into the and allows it to be soaked into the ground better. ground better.

Water ErosionWater Erosion

• When water travels down the same When water travels down the same slope time after time, it erodes a path slope time after time, it erodes a path into the slope. into the slope.

• As water continues to move down this As water continues to move down this path, it creates a groove on the slope path, it creates a groove on the slope called a channel. called a channel.

River System DevelopmentRiver System Development• Streams are part of river systems. The Streams are part of river systems. The

water comes from rills, gullies and smaller water comes from rills, gullies and smaller streams that are upstream. streams that are upstream.

• Run off enters streams, and these Run off enters streams, and these streams flow into rivers.streams flow into rivers.

• A drainage basin is the area of land from A drainage basin is the area of land from which a stream or river collects run off which a stream or river collects run off ( like a bathtub). Like water in a bathtub ( like a bathtub). Like water in a bathtub goes towards the drain, water in a river goes towards the drain, water in a river system flows to the main river. The system flows to the main river. The largest one being the Miss. River drainage largest one being the Miss. River drainage basin. basin.

Stages if Stream Stages if Stream DevelopmentDevelopment• Streams are classified as young, mature, or Streams are classified as young, mature, or

old.old.

• Young streams flow swiftly through steep Young streams flow swiftly through steep valleys. They may have white water rapids valleys. They may have white water rapids and waterfalls. and waterfalls.

• Mature streams is the next stage, and it Mature streams is the next stage, and it flows more smoothly through its valley. A flows more smoothly through its valley. A mature stream erodes along its sides and mature stream erodes along its sides and causes curves to form. Water in a shallow causes curves to form. Water in a shallow area will move slower, and water in a wider area will move slower, and water in a wider part of the channel will flow faster.part of the channel will flow faster.

• As the curve of a mature stream becomes a As the curve of a mature stream becomes a broad arc, it is known as a meanderbroad arc, it is known as a meander

Old StreamsOld Streams

• This is the last stage. Ole streams This is the last stage. Ole streams flow smoothly through a broad, flat flow smoothly through a broad, flat flood plain, the flat valley floor flood plain, the flat valley floor formed by a meandering stream.formed by a meandering stream.

• Old streams meet at drainage basins Old streams meet at drainage basins and form a major river.and form a major river.

Ground WaterGround Water

• Water that soaks into the ground and Water that soaks into the ground and collects in the pores of the soil is called collects in the pores of the soil is called ground waterground water

• Scientists estimate that 14% of fresh Scientists estimate that 14% of fresh water on Earth exists as ground water.water on Earth exists as ground water.

• Soil and rock are permeable because the Soil and rock are permeable because the pore spaces are connected and water can pore spaces are connected and water can pass through them. Rock and soil that do pass through them. Rock and soil that do not have large connected pores are not have large connected pores are considered impermeable and water considered impermeable and water cannot pass through them.cannot pass through them.

Importance of the oceanImportance of the ocean

• The oceans are important sources of The oceans are important sources of food, energy and minerals for many food, energy and minerals for many living organisms.living organisms.

• Energy sources like coal and oil can Energy sources like coal and oil can be found underneath the ocean floor.be found underneath the ocean floor.

• 1/3 of the worlds table salt is taken 1/3 of the worlds table salt is taken from the oceans salt water.from the oceans salt water.

• They also make the transportation of They also make the transportation of goods, by ship, possible.goods, by ship, possible.

OriginOrigin

• When the Earth first formed, its When the Earth first formed, its surface was mostly volcanoes and surface was mostly volcanoes and cooled volcanic rock.cooled volcanic rock.

• When all of these volcanoes erupted, When all of these volcanoes erupted, they released a lot of water vapor they released a lot of water vapor into the atmosphere.into the atmosphere.

• Over millions of years this water Over millions of years this water vapor gathered in the atmosphere vapor gathered in the atmosphere and condensed to form torrential and condensed to form torrential rains which formed our oceans today.rains which formed our oceans today.

CompositionComposition

• The oceans contain dissolved gasses like The oceans contain dissolved gasses like oxygen, carbon dioxide, and nitrogen.oxygen, carbon dioxide, and nitrogen.

• Waters salinity is the measure of Waters salinity is the measure of dissolved salt in seawater. Today's dissolved salt in seawater. Today's average is 3.5% of the oceans water is average is 3.5% of the oceans water is salt.salt.

• The oceans also contains many dissolved The oceans also contains many dissolved salts along with other elements like salts along with other elements like calcium, magnesium, and sodium.calcium, magnesium, and sodium.

Desalination Desalination

• Because the demand for freshwater is so high, Because the demand for freshwater is so high, scientists are trying to come up with scientists are trying to come up with technology to take the salt out of water.technology to take the salt out of water.

• They are doing so by using a desalination They are doing so by using a desalination plant.plant.

• This is a large peaked roof building that is This is a large peaked roof building that is filled with saltwater from oceans.filled with saltwater from oceans.

• The room is heated so the water evaporates The room is heated so the water evaporates and condenses on the ceiling, once it and condenses on the ceiling, once it condenses, it then drips down the ceiling as condenses, it then drips down the ceiling as freshwater into drums.freshwater into drums.

Ocean currentsOcean currents

• An ocean current is a mass An ocean current is a mass movement, or flow of ocean water. movement, or flow of ocean water. They are like rivers within oceans.They are like rivers within oceans.

• Surface currents move water Surface currents move water horizontally and are powered by horizontally and are powered by winds. These winds force the currents winds. These winds force the currents to move in a circular motion.to move in a circular motion.

• These currents only move the upper These currents only move the upper few hundred meters of ocean water.few hundred meters of ocean water.

Ocean currentsOcean currents

• Warm currents are shown with red Warm currents are shown with red lines and cold ones with blue lines.lines and cold ones with blue lines.

• West coast currents of the U.S. West coast currents of the U.S. originate at the poles and move originate at the poles and move down past Cal. down past Cal.

• Surface currents that flow along the Surface currents that flow along the East coast of the U.S. originate near East coast of the U.S. originate near the equator and are warmer.the equator and are warmer.

TidesTides• Tides are the rise and fall of sea level. Tides are the rise and fall of sea level.

They are created by giant waves that They are created by giant waves that are produced by the gravitational pull are produced by the gravitational pull of the sun and moon.of the sun and moon.

• Water levels moves out at low tide Water levels moves out at low tide and rise again at high tide. Tidal and rise again at high tide. Tidal range is the difference between high range is the difference between high and low tide ocean levels.and low tide ocean levels.

• Oceans react to the pull b/w the earth Oceans react to the pull b/w the earth and moon. 2 budges of water are and moon. 2 budges of water are always forming when the moon always forming when the moon rotates the earth rotates the earth

Tides and the moonTides and the moon

• Oceans react to the pull b/w the earth Oceans react to the pull b/w the earth and moon. 2 bulges of water are always and moon. 2 bulges of water are always forming when the moon rotates the forming when the moon rotates the earth.earth.

• One is going to be where the moon is One is going to be where the moon is closest to the earth and the other on the closest to the earth and the other on the opposite side.opposite side.

• These bulges cause high tides where These bulges cause high tides where the moon is closest to the earth, and the moon is closest to the earth, and the areas of the earth that the moon is the areas of the earth that the moon is not over at that time experience low not over at that time experience low tides.tides.

Spring and Neap tidesSpring and Neap tides• When the sun, moon and earth are When the sun, moon and earth are

all lined up it causes more all lined up it causes more gravitational pull and creates spring gravitational pull and creates spring tides, which make high tides higher tides, which make high tides higher and low tides lower than normal.and low tides lower than normal.

• When the sun, earth, and moon are When the sun, earth, and moon are at right angles to each other they at right angles to each other they cause neap tides, which give lower cause neap tides, which give lower high tides and higher low tides than high tides and higher low tides than normal.normal.

• H.W. pg 538 1-15 on loose leaf.H.W. pg 538 1-15 on loose leaf.