unit d grade 8 – water systems. where does the water we drink come from?
TRANSCRIPT
UNIT D
Grade 8 – Water Systems
Where does the water we drink come from?
Big Ideas of Water Systems
Water is crucial to life on EarthWater systems influence climate and weather
patternsWater is an important resource that needs to
be managed sustainable Chapter 10: Safe Drinking Water Chapter 11: Water Quality Chapter 12: Water, Weather, and Climate
Safe Drinking Water - Introduction
Why is it often unsafe to drink water directly from nature?
Why can’t fresh water just be pumped into our homes?
What do you think must happen in order for water to be safe for humans to consume?
KEY QUESTION
Where does water come from?Suggestions?
Looking Ahead…
• We use water in many different ways ever day.• Water circulates around Earth in the water
cycle.• The skills of analysis can be used to determine
personal water use and ways to reduce water use.
• Water must be treated before it is safe to drink.• The skills of technological problem solving can
be used to design and build a sample water filtration device.
• The media report on water-related issues in different ways.
Vocabulary
• Water cycle• Melting• Sublimination• Evaporation• Condensation• Deposition• Freezing• Runoff• Groundwater
• Aquifer• Water table• Precipitation• Polar ice sheet• Icecap• Glacier• Water treatment• Floc• Sustainability
10.2 What is Water?
OBJECTIVE: Demonstrate an understanding of the characteristics of the earth’s water systems and the influence of water systems on a specific region
Does water always look clean and pure?Clean vs. Dirty water sample
Why do we need water?
Helps the body transport substances to all the tissues and organs
Needed in order for chemical reactions to take place
Keeps the body coolEssential for our health
Describing Water
Most water in nature is not “pure” Some have a different colour or smell to them
They are usually a mixture of water and other substances
Some substances mixed with water are needed and some are dangerous
The Water Particle
Made up of HYDROGEN and OXYGEN (H2O)These particles are joined together
States of Water
• Solid (ice) – definite shape; water particles cannot move freely
• Liquid (water) – particles vibrate faster; free to move around
• Gas (water vapour) – particles are very far apart; have a lot of energy and move quickly in all directions
• They all behave differently
Page 269 - Homework
• Describe a particle of water. What other particles make up a particle of water?
• You are given a sample of tap water that is clear, yellowish, and odourless. Is this a sample of pure water? Explain.
• Choose one of the states of water– Draw a labeled diagram to show the arrangement of
water particles in this state.– Describe the arrangement of water particles in this
state
Page 269 - Homework
• Describe a particle of water. What other particles make up a particle of water?
• You are given a sample of tap water that is clear, yellowish, and odourless. Is this a sample of pure water? Explain.
• Choose one of the states of water– Draw a labeled diagram to show the arrangement of
water particles in this state.– Describe the arrangement of water particles in this
state
10.3 The Water Cycle
Water vapour is an invisible gasSteam coming off of a boiling kettle is not
water vapour…it is condensed liquid waterWater vapour that escapes from a kettle is
invisible, but, outside the kettle, the water vapour quickly condenses when it meets the cooler air to form a mist that we call “steam”
Changes of State• Handout• Melting: change of state from a solid to a liquid;
solid gains more thermal energy• Sublimination: change of state from a solid to a
gas without first becoming a liquid; solid gains thermal energy
• Evaporation: change of state from a liquid to a gas; liquid gains thermal energy
• Condensation: change of state from a gas to a liquid; gas loses thermal energy
• Despoition: change of state from a gas to a solid; gas loses thermal energy
• Freezing: change of state from a liquid to a solid; liquid loses thermal energy
Changes of state …
Condensation
EvaporationMelting
Freezing
GASLIQUIDSOLID
SUBLIMINATION
DEPOSITION
Increasing thermal energy of particles
Decrease thermal energy of particles
Melting, Evaporation and Sublimination in Nature
• Runoff: Water from precipitation and melting snow
• Groundwater: water that comes through soil and cracks in rocks; underground springs and wells
• Aquifer: a geological formation of loose rock or soil that is saturated in groundwater
• Water table: loose rock and soil below the Earth’s surface are saturated with water
Condensation, Freezing, and Deposition in Nature
Precipitation: solid or liquid water that falls to Earth’s surface
Polar ice sheet: sheet of ice covering the North or South Poles
Icecap: a large block of ice that permanently covers land
Glacier: a river of ice formed from snow; moves slowly downhill
Page 273 - Homework
• Look at Figure 2. Where can you find each of the three states of water?
• Describe the water cycle. Draw your own labelled diagram.
• Briefly describe how solid and liquid water may be converted to water vapour.
• Describe how water vapour changes into solid and liquid water above Earth’s surface.
• Does all surface runoff move directly into rivers, lakes, and oceans? Explain.
Page 273 - Homework
• Look at Figure 2. Where can you find each of the three states of water?
• Describe the water cycle. Draw your own labelled diagram.
• Briefly describe how solid and liquid water may be converted to water vapour.
• Describe how water vapour changes into solid and liquid water above Earth’s surface.
• Does all surface runoff move directly into rivers, lakes, and oceans? Explain.
10.5 Making Water Drinkable
What do you think is involved in the water treatment process?
What are some different methods to make our water drinkable?
In this section, we will be learning about the process for treating wastewater or sewage in a water treatment plant
The Water Treatment Process• Remove large objects from the water; the
screen at the end of the tube blocks large objects from entering
• Water enters a large tank where a chemical is added (alum); alum make clumps in the water where most of the waste goes to (floc)
• Water and floc enter a settling tank; floc settles to the bottom
• Partially clean water moves through a sand and charcoal filter which removes remaining waste solids and small pieces; water is now clear, colourless and odorless
• Water still may contain some bacteria and so chlorine and ozone can be added to kill these organisms
• The water is ready to use
Other Treatment Options
Type of Treatment How it works When it is used
Reverse Osmosis
Ultraviolet (UV) Radiation
Water Softening
Boiling
Page 278 - Homework
• List and describe the six main steps that water goes through in the water treatment process.
• Is clear, colourless, and odourless drinking water always safe to drink? Explain.
• Describe how the membrane works in the reverse osmosis process. Use a labeled diagram in your description.
• Why is it important to ensure that treated water remains safe to drink when it is stored after treatment?
• Describe one way to make stored water safe.
Page 278 - Homework
• List and describe the six main steps that water goes through in the water treatment process.
• Is clear, colourless, and odourless drinking water always safe to drink? Explain.
• Describe how the membrane works in the reverse osmosis process. Use a labeled diagram in your description.
• Why is it important to ensure that treated water remains safe to drink when it is stored after treatment?
• Describe one way to make stored water safe.
Chapter 10 Review
Page 284 and 285Review questions: #1-12
Chapter 10 Quiz on _______________
Chapter 11 – Water Quality
What does polluted water look like?Does it always look dirty?
Some substances and micro-organisms that pollute our water are not always visible
It may look clean but there is sill a possibility that it can be dirty
Chapter 11 Intro Photo
What is shown in the picture?What pollutants can you see in the water?How might have these pollutants enter the
body of water?
KEY QUESTION
What substances are in water, and where do they comes from?
Looking Ahead…
Only a tiny fraction of the water on Earth is fresh water available for out use.
Water can contain many ifferent contaminants.
The skills of scientific inquiry can be used to test water quality.
Water must be used sustainably.Wastewater must be treated before being
returmed to the environment.
Vocabulary
SalinityConcentrationDesalinationContaminantFertilizerHerbicidePesticideTurbid
Thermal pollutionWatershedBioremediationSewer systemBlackwaterGreywaterWastewaterStormwater runoff
11.1 Fresh Water and Salt Water
Can we drink salt water? Large quantities can be deadly Kidneys don’t have the ability to process a high
concentration of salt
Salt WaterSalt Water Fresh WaterFresh Water
Contains a lot of saltSwimmers can easily
float in the waterHas a lot of salinity
(the amount of salt in the water)
Has a greater density
The salinity in fresh water is less than 1%
Salt Water vs Fresh Water
Try This Activity…
Materials: Small graduated cylinder 2 cups or small bowls Marker Teaspoon tap water 2 paper labels Salt
Page 291 - Homework
What percentage of water on Earth is fresh water?
Describe two special characteristics of salt water.
Why are engineers developing desalination technologies?
Briefly describe a desalination process.What can make desalination expensive?Name two renewable energy sources that
can be used in desalination.
Page 291 - Homework
What percentage of water on Earth is fresh water?
Describe two special characteristics of salt water.
Why are engineers developing desalination technologies?
Briefly describe a desalination process.What can make desalination expensive?Name two renewable energy sources that
can be used in desalination.
11.2 Contaminants in Water
How does water become polluted?Where are some specific places where water
is contaminated?Contaminants: an unwanted substance in a
mixtureWhat human activities have an effect on
water sources? Farming, road salting, garbage dumping, burning
fossil fuels, etc.
Sources of Chemical Contaminants
SaltMineralsFertilizersHerbicides and PesticidesAcid RainOther Toxic Chemicals
Salt
Can come from road salt, gravel, and sand in the winter
When the snow melts, it carries the salt into nearby forests on washes into bodies of water
Minerals
Can come from rocks that dissolve into waterLimestone (example) is a soft rock that
dissolves in water which adds calcium carbonate to the water
Fertilizers
Fertilizer: a substance used to give nutrients to plants, usually to increase crop production
Fertilizers can be carried during rainfalls to streams and lades
Herbicides and Pesticides
Herbicides: a chemical substance used to kill or slow the growth of certain plants, often used to kill weeds that compete with crop plants
Pesticides: a chemical substance used to kill animal pests, often used to kill insects that damage crops Ex: DDT (kills flies, mosquitoes and potato beetles)
Acid Rain
Chemicals that are released into the air from burning of fossil fuels
These chemicals reach with water vapour to form acid rain
Other Toxic Chemicals
Transportation industryGarbage dump and sewageShip spills (oil spills)
Sources of Biological Contaminants
ManureE-coli (damages local water)Local water containing parasitesAnimal feces
Page 295 - Homework
Name two parts of the water cycle in which contaminants can be introduced.
What are the two main categories of contaminants in water? Why are they a problem?
Choose 2 chemical contaminants that could be found in a freshwater source. For each one, Identify a source of the contaminant Describe how the contaminant got into the water
Briefly describe how a biological contaminant was able to get into groundwater wells at Walkerton.
Page 295 - Homework
Name two parts of the water cycle in which contaminants can be introduced.
What are the two main categories of contaminants in water? Why are they a problem?
Choose 2 chemical contaminants that could be found in a freshwater source. For each one, Identify a source of the contaminant Describe how the contaminant got into the water
Briefly describe how a biological contaminant was able to get into groundwater wells at Walkerton.
11.3 Testing Water Quality
Water quality is an indicator of how good or bad the water in a certain system is
What would you classify as “good” water?What would you classify as “bad” water?
When Testing Water…
Look at the turbidityTest the temperatureFind out the acidity of the water (pH)Test the salt content (salinity)Look for other dissolved substances in the
water
Turbidity
Turbid: not clear; containing tiny specks of sediment or other solid matter Makes the water cloudy
Clear water is better than turbid water
Temperature
Warm water contains less dissolved oxygen than cold water
Thermal pollution: increasing the temperature of the water (kills the bacteria)
Acidity
Water is acidic if it contains chemicals such as sulfuric acid or nitric acid
We can measure the acidity with an indicator that has a different colour for every pH level
Water is acidic if it’s pH is below 7; basic if it is above 7
Salinity
You need a conductive apparatusElectricity is used
Other Dissolved Substances
ChlorineNitratesIron and copperCalcium and magnesium
Page 297 - Homework
List at least three factors mentioned in this section that decrease water quality.
How can you test a water source to see whether it is acidic or not?
What is thermal pollution? How do nuclear power plants contribute to thermal pollution?
How could each of the following substances enter a freshwater source? Chlorine - calcium Nitrates - acid
Page 297 - Homework
List at least three factors mentioned in this section that decrease water quality.
How can you test a water source to see whether it is acidic or not?
What is thermal pollution? How do nuclear power plants contribute to thermal pollution?
How could each of the following substances enter a freshwater source? Chlorine - calcium Nitrates - acid
11.4 Watersheds
The highest parts of North America are called the continental divides The divide the waters on each side, which helps the
water flow downwards
80% of Canada’s surface water goes towards the Arctic Ocean
Figure 1
Watershed
Watershed: an area surrounded by high land and drained by a river and its area; all the runoff in the watershed leaves the watershed at the same exit
Read page 299 and 300
Page 300 - Homework
Describe how a continental divide affects the direction of water flow over land.
Name a continental divide, and describe where it is.
Explain the meaning of the term “watershed”.
Briefly describe the role of a Conservation Authority.
What is the process called in which organisms are used to remove contaminants from the environment?
Page 300 - Homework
Describe how a continental divide affects the direction of water flow over land.
Name a continental divide, and describe where it is.
Explain the meaning of the term “watershed”.
Briefly describe the role of a Conservation Authority.
What is the process called in which organisms are used to remove contaminants from the environment?
11.7 Wastewater Treatment
Water goes through 5 stages of treatment Preliminary Treatment Primary Treatment Secondary Treatment Final Treatment Solids Processing
Preliminary Treatment
Wastewater passes through a bar screen which removes larger objects
The wastewater is slowed down and put into a tank where it settles
The sand, gravel and other heavy objects sink Water goes onto the next stage
Primary Treatment
The wastewater goes into a large settling tank
Sits for several hoursSolid particles settle at the bottom of the
tank
Secondary Treatment
A process that removes organic matter from wastewater
Oxygen is added which helps micro-organisms to grow which will eat the bacteria in the water
Any remaining solids continue to settle on the bottom
Final Treatment
Wastewater is disinfected to kill harmful organisms
Clean water is released into the lake
Solids Processing
The solids that were removed from the water in the primary and secondary treatment stages is sent to the digester
After 15 days, bio-solids (wet, soil-like material) are sent to the landfill or are incinerated
Types of Water
Blackwater: water that contains feces and urine; also called “sweage”
Greywater: water that has been used for cooking, laundry, bathing, or similar tasks
Wastewater: water that has been used or contaminated by human activity; blackwater and greywater
Stormwater runoff: water, usually from precipitation, that runs off roods, lawns and paved areas
Page 307 - Homework
Explain in your own words how greywater is different from blackwater.
List two sources of wastewater.What is the purpose of the primary stage of
sewage treatment?Explain the difference between a septic
system and a sewage system.Explain the difference between a septic
system and a sewage system.
Chapter 11 Review
Page 310 and 311Questions: #1-10, and 13
Quiz on ______________
Ch 12 – Water, Weather, and Climate
What do you think of when you hear the word water?
What do you think of when you hear the word weather and climate?
Do changes in climate effect the changes in weather? Changes in climate do not necessarily cause
immediate or predictable changes in weather (in the spring, the climate in Ontario is getting warmer, however, that does not mean that every spring day is warmer than the previous day)
Chapter 12 Introduction
What is in the picture on page 314?What is happening?Why do you think this is happening?
Flooding has happened from the river which causes erosion which collapses the road
What does this scene have to do with weather? More water than usual because of unexpected
weather changes which causes the river to overflow and the road to break apart
Looking Ahead
The climate of a region and the weather on any particular day, are affected by large bodies of surface water
Climate affects water’s temperature and changes of state on Earth
Research skills can be used to assess issues related to local and global water supply
Global warming is affecting water systems around the world
The long-term sustainability of water systems depends on how well we manage and care for water
KEY QUESTION
How do water systems, weather, and climate affect
each other?
Vocabulary
WeatherClimateHeat capacityHeat sink
ConvectionGlobal warmingFlood plain
12.1 Surface Water and Climate
OVERALL EXPECTATION: Demonstrate an understanding of the characteristics of Earth’s water systems and the influence of water systems on a specific region
What are factors that affect our climate? Distance from the equator How close we are to bodies of water Altitude (height above sea level)
Facts
What is the climate in areas that are higher above sea level? Coller climates Top of mountains are usually cooler
What is the climate in areas that are close to bodies of water? Winds and ocean currents effect climate
What is the climate like in areas close to the equator? Hotter climate
What is the climate like where we live?
What is the difference between weather and climate?
CLIMATE is what we expect (seasonal)WEATHER is what we get (day to day)
Temperatures in Air and on Land Activity?
Weather and Climate
Weather: day-to-day environmental conditions in a given place at a given time; includes temperature, cloud cover, wind speed, and precipitation
Climate: an average of weather conditions in an area over 30 years
Causes of Temperature Differences
How much energy is coming from the sunDifferent seasons
Heat Capacity
The Earth supports life because of its heat capacity
Heat capacity: a measure of the amount of thermal energy needed to increase temperature; how much thermal energy an object can hold the higher the heat capacity of a substance, the more
thermal energy it can store Soil and rock can not store as much heat as water; they
need less thermal energy to heat up Gravel or rocks release thermal energy faster than
water
Heat Sinks and Climate
Heat sink: matter that absorbs thermal energy but does not change state or significantly increase in temperature Water (energy is always moving around and energy
goes through the entire body) Ocean water never really heats up (it does get warm)
Convection: circulating currents heat up the gas or liquid from fast or slow moving particles Water circulates Air circulates
Page 319 – Homework
What is the difference between weather and climate?
Explain in your own words how the heat capacity of water makes any body of water a good heat sink.
Describe how warm water at the surface of a lake or ocean mixes with deeper, cooler water.
Why do areas close to large bodies of water have milder climate than inland?
t
Page 319 – Homework
What is the difference between weather and climate?
Explain in your own words how the heat capacity of water makes any body of water a good heat sink.
Describe how warm water at the surface of a lake or ocean mixes with deeper, cooler water.
Why do areas close to large bodies of water have milder climate than inland?
12.2 Glaciers, Polar Ice and Global Warming
Are greenhouse gases and global warming the same thing? No…the greenhouse effect has an effect on global
warming but they are not the same thing
What is the greenhouse effect? Carbon dioxide and methane are some examples of
greenhouse gases More thermal energy gets trapped in the atmosphere
What do you already know about global warming?
The Effects of Climate Change
When climate is cold, there is an ice build up on glaciers; more ice covers the land
If there is more precipitation or if more ice melts, then the ice coverings start to melt
Global Warming: an increase in the Earth’s average atmospheric temperature
What happens in Canada?
Global warming is lowering the water levels in Lake Ontario
Water is evaporating quickly
El Nino
A large current of warm water that forms in the Pacific Ocean
Warm water current moves north which warms the air above
Warm air moves inland which can increase the temperatures in winter
Less snow and precipitation
Storms and Hurricanes
Warm air currents that develop into hurricanes
Hurricane winds push ocean water around to create storms
Page 322 - Homework
The Athabasca Glacier in Western Canada continues to shrink every year. What does this suggest about the climate in that region? Explain your answer.
In your own words, explain how rising sea levels are an indication of global warming.
Explain what is happening to water levels in the Great Lakes.
What is El Nino? Describe the effects of El Nino on Canadian weather.
Explain how hurricanes form.
Page 322 - Homework
The Athabasca Glacier in Western Canada continues to shrink every year. What does this suggest about the climate in that region? Explain your answer.
In your own words, explain how rising sea levels are an indication of global warming.
Explain what is happening to water levels in the Great Lakes.
What is El Nino? Describe the effects of El Nino on Canadian weather.
Explain how hurricanes form.
FloodsFloods DroughtsDroughts
Caused by heavy rainfall or rapid snow melt
Add moisture to dry land, provide nutrients, etc.
Caused by dry weather conditions where water evaporates faster than it is replaced
Can cause forest fires
12.4 Floods and Droughts
FloodsType 1: Rapid snowmelt or heavy rainType 2: Flash floods are the most deadly and
damaging Produced by a sudden storm
Type 3: Storm surges are floods that occur along coastlines when hurricanes come ashore Very dangerous One came after Hurricane Katrina which killed and
destroyed many
Type 4: Ice jam floods usually happen in the spring and is from river ice breaking up and being jammed into narrow parts of the river
Preventing Floods
New homes should not be built on flood plains (low area of land alongside a river)
Using dams to control water
Droughts
Less than 2.5 cm of precipitation annually = desert
6 months or more with no rain or snow = season drought
Humans use it to drink and bottle water to sell and therefore we lose even more water
Page 327 - Homework
How are floods and droughts sometimes good for the natural environment?
Briefly describe two strategies that would reduce the chances of homes being damaged by floods.
Does damming a river make the water source more sustainable? Explain your answer.
What human activities worsen the effects of drought?
How does soil compaction affect the water system?
12.6 Water is Life
A lot of people do not have access to water while others over use it
World’s first “Water Day” – March 22, 2005
Page 330 - Homework
Describe, in your own words, the United Nations Millennium Declaration on water rights.
Explain how buying and selling water conflicts with the idea that access to clean water is a basic human right.
Chapter 12 Summary
Page 334 and 335Questions on page 336 and 337, #1-10
Unit D Summary
Questions on page 340 and 341#1-8, 10 and 13
Unit D test on _____________