Grade 8 – Water Systems Unit D.

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 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 2 glasses of water (one clean and one dirty) Ask students which one they would rather drink and explain. Is the water pure? Is the water in each glass a pure substance (made up of one component) or a mixture (made up of 2 or more components)?

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 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 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 Photocopy BLM for students

Changes of state … Increasing thermal energy of particles SOLID LIQUID
SUBLIMINATION Condensation Freezing Melting Evaporation SOLID LIQUID GAS DEPOSITION 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 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 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 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 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 Concentration Desalination Contaminant Fertilizer
Herbicide Pesticide Turbid Thermal pollution Watershed Bioremediation Sewer system Blackwater Greywater Wastewater 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
Contains a lot of salt Swimmers can easily float in the water Has a lot of salinity (the amount of salt in the water) Has a greater density The salinity in fresh 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.

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 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 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 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 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 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 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.

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? 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

How do water systems, weather, and climate affect each other?
KEY QUESTION How do water systems, weather, and climate affect each other?

Vocabulary Weather Climate Heat capacity Heat sink Convection
Global warming Flood 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? Photocopy BLM 12.1 activity from manual

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 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

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 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.

12.4 Floods and Droughts 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 Venn Diagram for Floods/Droughts Photocopy for all students

Floods Type 1: Rapid snowmelt or heavy rain
Type 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 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 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 _____________

Grade 8 – Water Systems Unit D.

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