Transcript Global warming & its effects

Global warming & its effects
 What will be the effect of global warming on glaciers
and the polar icecap?
 What will happen to ocean levels and coastal
communities in our region?
 Read p. 27 and discuss!
The last ice age!
(you think our winters are cold!)
 Last ice age began about 120 000 years ago, and ended
only 11 000 years ago!
 Almost all of Canada was covered by a glacier!
Read pp. 28-30
Solving problems using science
 Can science alone solve problems like global warming?
 Cultural views, societal views, etc. are very important
part of solving problems.
 Questions 1-5, p. 28
 Questions 1-8, p. 35
 Pause and Reflect... p.35
Chapter 2
Exploration of ocean basins
 Read p. 38-46
Ocean basins
 The surface of the ocean floor is as varied as the land.
 The five major oceans, from largest to smallest, are
 the Pacific
 the Atlantic
 the Indian
 the Southern
 the Arctic
 The low points in the oceans are called basins.
 Oceans are vital to life, as they control temperature,
create weather patterns and provide
water for water cycles.
 Basins becoming bigger – demo (p. 41)
Ocean basins (cont’d)
 The ocean basins contain mountains, valleys and
plains.
 The largest changes to the ocean basin occur through
the movement of tectonic plates, although there is also
erosion via storms, earthquakes and icebergs.
Origin of ocean water
 Oceans have filled over hundreds of millions of years.
 Scientists believe the oceans are more than 3 billion
years old.
 Water may have originally been released from volcanic
eruptions when the vapour from the eruption cooled
and condensed.
 Some believe the water came from ice comets.
Origin (cont’d)
 Pangea began to split up due to plate tectonics.
 Earth’s surface is made of large, slow-moving sections
of rock called tectonic plates.
 http://www.ucmp.berkeley.edu/geology/anim1.html
Technologies for studying ocean basins
 Read pp. 46-49
 STSE
 Define the following technologies in your notebook:
 Sonar
 Satellites
 Core sampling
 Underwater photography/videography
 Deep sea submersibles
 Diving
 Write a paragraph explaining how these technologies
have improved over time. (ex. Diving vs. Submersible
and wire line depth probe vs. Sonar)
Continental margins and others
 Abyssal plains are the pieces of oceanic crust between
a spreading mid-ocean ridge and the trench it
disappears into.
 Continental shelf is the submerged part of the
continent between the coast and the edge of the basin.
 Continental slope is the section that slopes downward
to the seafloor.
 Mid-ocean ridge is where the sea floor is still being
formed by volcanic eruptions. Two plates are being
pushed apart (magma oozes out from the core and
hardens) and a mountain change forms!
Draw a profile diagram include:
continental shelf
continental slope
abyssal plain
mid-ocean ridge
 Read Science Watch p. 52
 Do questions 1-11, p. 53.
Ocean Currents
 Read pp. 54-61
Ocean Currents
 There are more than 20 major currents which move
large amounts of water predictably around the oceans.
 Currents move large quantities of water, minerals, solar
energy, oxygen and carbon dioxide, plankton and fish.
 Currents are caused and driven by water
density and salt content, the wind, the
spin of Earth, coastlines and the moon.
 Largest current is the Antarctic
Circumpolar Current in the
Southern Ocean, at 24 000 km long
 Ocean currents are either
 Surface currents (0 - 200 m)
 Deep water currents (200 m and deeper)
What makes surface currents move?
 Wind
 As air warms from solar energy, it rises, and cooler air rushes to replace
it. This creates wind.
 As the wind passes along the surface of the water, it bumps the water
molecules and moves them along in the same direction.
 Spin of the Earth
 Earth spins from West to East (counter clockwise)
 The Coriolis effect deflects winds and currents to
the right/East in the Northern hemisphere
(opposite in the Southern hemisphere)
http://video.google.ca/videosearch?q=the%20physics%20of%20weather&h
l=en&rlz=1T4GWYE_enCA242CA242&um=1&ie=UTF-8&sa=N&tab=wv#
 Shape of continents
 Currents move through the oceans and around
the continents like rocks in a stream.
What makes deep currents move?
 Water temperature
 Like air, warm water rises, and cool water falls
 Density current = cool, dense water moving on an ocean floor.
 Three layers of water dependent on temperature:
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Surface: 0 - 200 m, warmest
Thermocline: 200 m - 1 km, rapidly cools
Deep water: 1 km and deeper, just above freezing
 Water salinity
 Adding fresh water decreases salinity
 Evaporation and freezing increases salinity
 Densest ocean waters at the poles
 Upwelling occurs when nutrient-rich
cold water finally moves up to the surface
 Convection current demo... P. 36 Curriculum Guide
 Questions 1-10, p. 63
Ocean Waves
 Read pp. 64-66
Ocean Waves
 Most waves are created by wind.
 In open ocean, waves are called swells.
 Swells “break” in shallow water, called breakers.
 The largest waves are tsunamis, caused by undersea
earthquakes, landslides or volcanic eruptions.
 Tsunami - From The Discovery Channel-B (12-26-04)
◦ http://video.google.com/videoplay?docid=-
4333412395835151021&vt=lf&hl=en
 Newfoundland Tsunami and photos
 http://www.collectionscanada.gc.ca/sos/002028-1100e.html
Breakers
 As a wave approaches the shore, its wavelength
decreases and its height increases.
Class project!
 Newfoundland Tsunami
 Make a poster about the 1929 Newfoundland Tsunami
 Include:
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Date
Location (map)
Cause
Death toll
Destruction
Pictures
Tides
 Read p.69-71
Tides
 Hopewell Rocks – Bay of Fundy Tides
◦ http://video.google.ca/videoplay?docid=3956711618129258915&ei=-1W5SNTFH4yawH96NnYDA&q=fundy+tides&vt=lf
 Tides are caused by gravities of Earth and the Moon.
 High tides occur where the Moon is
closest to Earth (and opposite side)
 Low tides occur at 90º to the high tides.
 Tidal range (difference between
high and low) averages 2 m in NL.
 The Sun’s gravity, when lined up
properly, can produce extreme tides.
 These are called spring tides
 When the Sun, Moon and Earth are not lined up,
the tides are called neap tides.
 Questions 1-4, p.71
Shoreline interactions
 Read pp. 66-69
Interactions at shorelines
 Waves erode coastal areas based on the force of the waves, and
the composition of the shoreline.
 Headlands made up of harder rock, and erode less, but absorb
most wave force.
 Bays occur between headlands, are generally calm.
 http://maps.google.ca/maps?sourceid=navclient&ie=UTF8&rlz=1T4GWYE_enCA242CA242&q=Goose%20bay&um=1&sa=
N&tab=wl
 Sea stacks are extra-hard
rock left behind from eroded
headlands.
Reminder from Grade 7...
 Weathering – breakdown of rocks into smaller
particles
 Erosion – the movement of those weathered particles
 Deposition – when eroded material is left behin
Shorelines
 Waves have the power to erode shorelines and deposit
sediments on the shore.
 Tides work together with waves and determine the
range of shoreline that can be affected by wave action.
 The interaction with shorelines depend on:
 Shape of the shoreline
 Slope of the shoreline (shallow means deposition of
sediments, steep means erosion)
 Type of rock material (sandstone erodes faster than
shale)
 Wave energy
Limestone
Class Activity
 6 groups (4/5 per group)
 You are to research the processes of erosion and
deposition that result from wave action and water flow
on one of the following: beaches, shoal, sand bars, sea
caves, sea stacks, sea arches
 Present your findings on a poster. Be sure to include
pictures and NL location!
Prevention/reduction of wave
action along shorelines
 Breakwaters
http://maps.google.ca/maps?sourceid=navclient&ie=U
TF8&rlz=1T4GWYE_enCA242CA242&q=foxtrap%20mari
na&um=1&sa=N&tab=wl
 Jetties/wharves
 Vegetation
 Questions 1-5, p.69
 Read Wild, Weird, Wonderful, p. 76 (The Spout!)
 http://video.google.ca/videosearch?sourceid=navclient&
ie=UTF8&rlz=1T4GWYE_enCA242CA242&q=the%20spout%20e
ast%20coast%20trail&um=1&sa=N&tab=wv#
 Questions 1-13, p. 77
 Foldable for review! p. 39
 http://video.google.ca/videoplay?docid=669595010475
6107303&ei=pv7fSJrxFoT0gGSy4yiCw&q=the+spout+east+coast+trail&vt=lf
 List 10 points/key terms in your notebook shown in the
video that we have discussed this chapter.
 Quiz!
 Test!