| Students will:|
| Are you ready for a "cool" experience? I mean a really
cool experience? In honor of the International Polar Year, we're going to focus
in on polar oceanography. Odds are you live in "the mid-latitudes,"
a geographic region between about 23.5° and 66.5° latitude. According
to the U.S. National Weather Service, much of the world's population lives in
the mid-latitudes. Since the mid-latitudes are removed from polar regions by thousands
of kilometers, you may wonder "What is the value of studying the oceans at
the top or bottom of the world? and how might events in that region affect us
here in the mid-latitudes?" Consider this fact: Over 70 percent of
our planet's surface is covered by water. Water by its nature has a high heat
capacity, meaning it can absorb, store and release tremendous amounts of energy.
Much of this energy is exchanged with the lower atmosphere, creating a strong
connection between the two and making world climate largely dependent upon the
ocean and currents running within it. |
PART I: A VIRTUAL VISIT TO THE TOP OF THE WORLD
Distribute "Worksheet: A Virtual Visit to the Top of the World" (and make the reference sheets "U.S. Map," "Images from the Arctic" and "North Pole Weather Data From 2007" available as handouts or overheads if your class does not have Internet access).
Ask students to ponder what it would be like to visit the "top of the world." Ask them to respond to the worksheet questions, which are designed to generate class discussion. Have your students record their responses and questions raised on the handout.
Consult the for answers and additional guidance for the Virtual Visit Worksheet.
Remind the students of their overall goal to understand polar oceanography.
Ask students to summarize the main ideas explored thus far by creating a concept map or an outline. PART II: EXPLORING GLOBAL OCEAN CURRENTS
The first part of this lesson introduced you to the conditions experienced at the "top of the world," establishing that the Arctic Ocean underlies the ice surrounding the North Pole. We know that conditions experienced in the Arctic (and Antarctic) are quite different from those experienced where most people live. To begin to look for connections between these two diverse regions located thousands of kilometers apart, we will conduct a series of experiments designed to explore the connections between three major Earth systems: the atmosphere, the hydrosphere and the cryosphere.
Provide students the definitions of "atmosphere," "hydrosphere," "cryosphere" and "biosphere":
Do ocean currents affect coastal climates?
The resources below enable you to access climatic data for two communities: St. Mawgan, England, and Daniels Harbour, Newfoundland, Canada. Both communities are located near 50°N latitude. St. Mawgan is situated on the southwestern coast of England along the eastern shores of the Atlantic Ocean. Daniels Harbour is located in Newfoundland near the western shores of the Atlantic Ocean. Follow the instructions below to collect climate data, process them and then finally analyze the data.
Collect the climate data: Process the data: Analyze the data: PART IV: EVIDENCE OF CHANGE IN THE ARCTIC
Next, let's return to the Arctic and search for evidence of change. We will ask the question: Are climatic conditions changing in the Arctic and if so, how might these changes affect ocean currents? Teacher Answer: The melting ice is adding fresh water to the Arctic Ocean. This lowers the salinity of the "open ocean" waters in that region. Since the water is less dense, its tendency to sink (due to extreme density) is reduced or eliminated. Teacher answer: Think of the entire ocean current system as a giant conveyor belt. If one part of the belt breaks down, the balance of the belt elsewhere will be significantly changed. Teacher answer: Fresher water carried to the mid-latitudes would eliminate the distinction between the Gulf Stream and the surrounding "open ocean" waters. In other words, the Gulf Stream is essentially floating on denser ocean waters as it carries warm water (and its energy) away from the Equator and towards the North Pole. If the density difference becomes minimal (or non-existent), the current will cease to have a recognizable identity -or in simple English - "no more Gulf Stream!" Some scientists believe this could happen over a very short period of time and may in fact be what happened during the "little ice age" that deeply impacted Europe and parts of North America.
To summarize this topic, distribute the article "Changes at Poles Drive Global Warming."
Alternatively, students may watch the online video, "Polar Warming."
Hold a full class discussion to summarize the main ideas presented within the activity:
Distribute the article "Polar Year Explores How Earth Systems Interact."
Ask students to define "International Polar Year" and create of list reasons that research at the poles could be relevant to their lives. Ask students to describe the Arctic's physical environment and the reasons why it is so different from the environment students experience in the mid-latitudes. PART II:
Distribute "Extension Activity: Exploring Global Ocean Currents". Students will need Internet access to complete this activity. PART III: 1. Much of the observed difference between the temperature patterns can be attributed to prevailing winds and the influence of the Atlantic Ocean and the (warm) Gulf Stream (also known as the "North Atlantic Drift"). How might the climate change in England if the Gulf Stream were to "collapse"? If this change were to occur, what else or what other systems would be affected? Explain.
2. Use the Web site to explore climatic data worldwide. Ask students to identify coastal cities on divergent coastlines with equivalent latitudes and explore differences in their climatic patterns using what they know about wind and ocean currents. PART IV: 1. Have students research causes of global climate change and actions that may arrest the current warming trend. Encourage students to consider the societal and economic implications of any remediation they propose. (Ask students whether a push to produce alternative fuels, such as ethanol, will reduce carbon dioxide emissions. Because ethanol is also a hydrocarbon, it won't reduce emissions. Other strategies may cost more. The NewsHour Extra lesson plan "Alternative Fuels and Alternative Cars" is available.
2. Ask students to prepare a poster illustrating what they have learned, detailing the changes that may result from continued global warming in polar regions and on biotic communities living within. (Issues addressed may include climate change in their region; changes in flora, fauna, crops and growing seasons - some of which can be anticipated and some of which can not. In other words, global change could bring about some surprising changes.)