Transcript Grade 8 – Water Systems

Grade 8 – Water Systems
UNIT D
Where does the water we drink come from?
Big Ideas of Water Systems
 Water is crucial to life on Earth
 Water systems influence climate and weather
patterns
 Water is an important resource that needs to be
managed sustainable
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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
• Aquifer
• Melting
• Water table
• Sublimination
• Precipitation
• Evaporation
• Polar ice sheet
• Condensation
• Icecap
• Deposition
• Glacier
• Freezing
• Water treatment
• Runoff
• Floc
• Groundwater
• 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 cool
 Essential 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
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–
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 gas
 Steam coming off of a boiling kettle is not water
vapour…it is condensed liquid water
 Water 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
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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 …
Increasing thermal energy of particles
SUBLIMINATION
Condensation
Freezing
Melting
Evaporation
SOLID
LIQUID
DEPOSITION
Decrease thermal energy of particles
GAS
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
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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
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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
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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
Reverse Osmosis
Ultraviolet (UV)
Radiation
Water Softening
Boiling
How it works
When it is used
Page 278 - Homework
• List and describe the six main steps that water goes
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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
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•
•
•
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 285
 Review 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
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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
 Salinity
 Thermal pollution
 Concentration
 Watershed
 Desalination
 Bioremediation
 Contaminant
 Sewer system
 Fertilizer
 Blackwater
 Herbicide
 Greywater
 Pesticide
 Wastewater
 Turbid
 Stormwater 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 Water vs Fresh Water
Salt Water
Fresh Water
 Contains a lot of salt
 The salinity in fresh
 Swimmers can easily
float in the water
 Has a lot of salinity
(the amount of salt in
the water)
 Has a greater density
water is less than 1%
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 mixture
 What human activities have an effect on water
sources?

Farming, road salting, garbage dumping, burning fossil fuels,
etc.
Sources of Chemical Contaminants
 Salt
 Minerals
 Fertilizers
 Herbicides and Pesticides
 Acid Rain
 Other 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 water
 Limestone (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 industry
 Garbage dump and sewage
 Ship spills (oil spills)
Sources of Biological Contaminants
 Manure
 E-coli (damages local water)
 Local water containing parasites
 Animal 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 turbidity
 Test the temperature
 Find 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
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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 apparatus
 Electricity is used
Other Dissolved Substances
 Chlorine
 Nitrates
 Iron and copper
 Calcium 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?
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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?
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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
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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
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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 hours
 Solid 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
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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 311
 Questions: #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?
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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
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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
 Weather
 Convection
 Climate
 Global warming
 Heat capacity
 Flood plain
 Heat sink
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?
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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?
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Coller climates
Top of mountains are usually cooler
 What is the climate in areas that are close to bodies
of water?
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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 sun
 Different 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
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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
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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
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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?
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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
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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
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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.
12.4 Floods and Droughts
Floods
Droughts
 Caused by heavy
 Caused by dry weather
rainfall or rapid snow
melt
 Add moisture to dry
land, provide nutrients,
etc.
conditions where water
evaporates faster than
it is replaced
 Can cause forest fires
Floods
 Type 1: Rapid snowmelt or heavy rain
 Type 2: Flash floods are the most deadly and
damaging
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Produced by a sudden storm
 Type 3: Storm surges are floods that occur along
coastlines when hurricanes come ashore
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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
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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 335
 Questions 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 _____________