Transcript Sample PowerPoint

CHAPTER
Water, Weather, and Climate
12
KEY QUESTION: How do water systems, weather, and climate affect each other?
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.
• The skills of scientific inquiry can be used to compare water use around the
world.
CHAPTER
Water, Weather, and Climate — Activity
•
Looking at the map below and the four major cities indicated,
predict which cities are coldest to warmest in the winter by
ranking them 1-4.
•
Coldest City: 1.
2.
3.
4.
•
Give reasons for your choices.
•
See next slide for
city temperatures.
12
CHAPTER
Water, Weather, and Climate — Activity
•
Did your predictions match the temperatures given? Record
the actual ranking next to your guesses.
•
Can you predict a trend with
temperatures and city location?
•
Read Chapter 12.1 to learn
more about weather and
climate.
12
CHAPTER
Reading Science and Technology
And Here is a Severe Weather Warning…
12
Text Genres: The Comic Strip
To understand this comic strip, you need to read
in a non-linear manner, scanning both the
pictures and text to follow the story. You may also
need to make connections between pictures, text,
and your background knowledge. Sometimes, a
message is hidden and you must make an
inference to figure out the meaning. Read the
comic strip, then work with a partner to discuss
the following:
1. Some of the text is spoken by characters, while
some of the text represents what they are
hearing. What helps you distinguish between the
two?
2. What inference can you make about why the
Rideau River area flooded?
3. Describe the characters’ feelings in the last
frame. Why are they feeling this way. How do you
know?
12.1
Surface Water and Climate
• Weather is a set of environmental conditions that changes from day to day.
• Climate, on the other hand, is a set of environmental conditions averaged
over 30 years. It does not describe any particular event at any particular time.
• Energy from the Sun drives the evaporation of water in the water cycle and
also heats Earth’s surface. At night, Earth cools down and radiates out its
energy.
• The high heat capacity of water means it can store and release more thermal
energy than soil or rock. Water helps keep Earth’s temperature fairly constant
from day to night
• When air becomes warm, it becomes less dense. This difference in density
causes air movements called convection currents.
• Inland cities experience colder winters and hotter summers that cities near
large bodies of water.
weather
climate
heat capacity
heat sink
convection
Glaciers, Polar Ice, and Global Warming
•
12.2
Glaciers, icecaps, and polar ice sheets are sensitive indicators of
changes in climate.
global warming
•
When the climate is cold for centuries the ice in glaciers builds up.
If there is less precipitation than usual for several years, or if more
ice melts than usual, then the ice cover starts to shrink.
•
Climate scientists believe that the shrinking ice is a sign that the
temperature of Earth’s surface is gradually rising – a process
called global warming.
•
Global warming is lowering the water levels in the Great Lakes
because it is evaporating faster than it is being replaced with
precipitation.
•
Global warming melts glaciers and icecaps,
and warms ocean currents and air currents.
Water Exports (Explore and Issue Critically)
•
A multinational company has had a permit to extract water from a
local water source near Guelph, Ontario, for the past few years, to
sell as bottled spring water. Citizens are worried about drawing
too much water from one aquifer. In 2008, the Ministry of the
Environment rejected the five-year renewal request to extract
water, but granted a two-year renewal.
•
Share your letter with another student who has taken a different
position. Discuss the rationale behind your respective choices.
12.3
Floods and Droughts
•
Floods usually result from heavy rainfall or rapid snowmelt.
•
Flash floods are generally produced by a sudden storm that
stalls over one location.
•
Ice-jam floods usually occur in the spring along Ontario’s
rivers.
•
Homes should not be built on, or too close to, flood plains
(the low area of land alongside a river).
•
Droughts are caused by dry weather conditions where water
evaporates faster than it is replenished.
•
Water shortages are often caused by human activities, such
as damming rivers, or removing water for irrigation and
bottling.
•
Vegetation and trees help prevent water loss during dry
periods.
12.4
flood plain
Global Access to Safe
Drinking Water (Perform an Activity)
•
In this activity, you will try to represent the difficulties in obtaining
safe drinking water experienced by people in various countries.
Equipment and Materials
12.5
Global Access to Safe
Drinking Water (Perform an Activity)
Safety
Never run in the science classroom
12.5
Water is Life
•
Over 1 billion people on Earth (one-sixth of the world
population) do not have access to safe drinking water, while
others waste water daily.
•
The world’s first “Water Day” was March 22, 2005. This day
marked the start of the “Water for Life” decade, when the UN
announced a ten-year target to achieve:
•
To reduce by half the number of people that do not have
access to safe drinking water and basic sanitation by the
year 2015.
•
Access to sufficient clean water is a fundamental human
right.
•
Access to clean water is crucial to everyone for health, food
production, and
economic development.
•
The why do the “water-rich” nations treat water as a product
they can package and sell?
12.6
Water Footprints
(Perform an Activity)
•
In this activity, you will compare the water footprints of “water-rich”
countries with those of “water-poor” countries.
12.7
CHAPTER
Summary – Looking Back
• The climate of a region, and the weather on any particular day,
are affected by large bodies of surface water.
• Water has a high heat capacity. It can absorb or release a lot of
thermal energy without changing its temperature significantly.
Water is a heat sink.
• Lakes and oceans act as heat sinks, making the climate milder
in coastal and lakeside areas than in inland areas.
• The difference in temperature between air over water and air
over land causes convection currents in the air (wind).
• Floods occur when there is too much rain and meltwater;
streams and rivers overflow their banks. Droughts
occur when there is not enough rain;
streams, rivers, and lakes dry up.
12
CHAPTER
Summary – Looking Back
• Climate affects water’s temperature and changes of state on Earth.
• Near the North and South poles, precipitation is in the form of snow.
The snow builds up over centuries, forming glaciers, ice sheets, and
icecaps.
• Near the Equator, precipitation is in the form of rain.
• Between the Equator and the poles, precipitation may be in the form
of snow for some of the year, but this snow melts each spring.
• The warmer the climate, the more easily surface water evaporates,
which may lead to droughts.
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CHAPTER
Summary – Looking Back
• Research skills can be used to assess issues related to local and
global water supply.
• Different media sources can be used to research issues related to
exporting water.
• Media sources present differing opinions on water issues.
• Global warming is affecting water systems around the world.
• Global warming is causing glaciers, ice sheets, and icecaps to melt.
This results in more water flowing into the oceans.
• Global warming is increasing the temperature of Earth’s surface
water.
• Sea levels are rising as the global temperature increase because
warmer water has a greater volume than cooler water.
12
CHAPTER
Summary – Looking Back
• The long-term sustainability of water systems depends on how well
we manage and care for water.
• Water use must be carefully planned and managed to ensure that
there will be enough clean water to meet the needs of people around
the world.
• Human activity affects the flow of water and the quality of water in a
local water system. Withdrawing water for drinking, irrigation, and
export reduces our water supply.
• The skills of scientific inquiry can be used to compare water use
around the world.
• Water footprints can be used to compare water use among
countries.
• Water footprints can also be used to identify areas in which we can
reduce water.
12
CHAPTER
Quiz
Multiple choice
For each question, select the best answer from the four alternatives.
1. A description of the environmental conditions averaged over
many years is called…
a) The weather.
b) The climate.
c) Heat capacity
d) Global warming.
2. Global warming is causing the Great Lakes’ water levels to…
a) Rise.
b) Fall.
c) Stay the same.
d) Go up and down.
3. Access to sufficient clean water is… ?
a) A privilege.
b) A basic human right.
c) A luxury.
d) Not necessary.
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CHAPTER
Quiz
True/False
Indicate whether each of the statements is TRUE or FALSE. If you
think the statement is false, rewrite it to make it true.
4. The lower the heat capacity of a substance, the more thermal
energy it can store.
5. Heat sinks can absorb a lot of thermal energy without
significantly increasing in temperature.
6. A rise in ocean temperatures can mean smaller, and less
frequent storms.
7. Trees and vegetation naturally resist droughts.
8. Human activities often cause floods.
12
CHAPTER
Quiz
Short answer
Write a short answer to each of these questions.
9. Describe why coastal cities experience milder winters and cooler
summers than inland cities?
10. Explain the following diagram in your own words, referencing
density and temperature relationships.
12
CHAPTER
Quiz Answers
Multiple choice
For each question, select the best answer from the four alternatives.
1. A description of the environmental conditions averaged over many
years is called…
a) The weather.
b) The climate.
c) Heat capacity
d) Global warming.
2. Global warming is causing the Great Lakes’ water levels to…
a) Rise.
b) Fall.
c) Stay the same.
d) Go up and down.
3. Access to sufficient clean water is… ?
a) A privilege.
b) A basic human right.
c) A luxury.
d) Not necessary.
12
CHAPTER
Quiz
True/False
Indicate whether each of the statements is TRUE or FALSE. If you
think the statement is false, rewrite it to make it true.
4. FALSE; The higher the heat capacity of a substance, the more
thermal energy it can store.
5. TRUE; Heat sinks can absorb a lot of thermal energy without
significantly increasing in temperature.
6. FALSE; A rise in ocean temperatures can mean larger, and
more frequent storms.
7. TRUE; Trees and vegetation naturally resist droughts.
8. FALSE; Natural disasters cause floods.
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CHAPTER
Quiz
Short answer
Write a short answer to each of these questions.
9. Describe why coastal cities experience milder winters and cooler
summers than inland cities?
Answers may vary.
Water has a high heat capacity and can both store and
release large amounts of thermal energy without its
temperature changing drastically. In the winter, water can
keep coastal cities warmer by releasing thermal energy, while
in the summer water can absorb thermal energy.
10. Explain the following diagram in your own words, referencing
density and temperature relationships.
Answers may vary.
During the day, the land heats up faster than the water, which
then warms the air above it. The air over the water remains
cool. As the warmer, less dense air rises, the heavier, cooler
air replaces it generating wind called “convection currents.”
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UNIT
Solving a Water Issue
(Unit Task)
In the Unit Task, you will find out about an award that is being offered for a
solution to a problem involving water. You will choose an issue that may be
affecting a water source anywhere in the world. You will be asked to prepare
and test an action plan to address the issue. Or, you may design, build, and test
a prototype of a device that solves a water problem. Whichever option you
choose, you will collect data during trials. You will then use your data in a news
media release that describes the success of your action plan or device
D