Module VIII - Artic Cryosphere Systems

Essential Question:
How are Arctic sea-ice, climate and culture all connected?


Icy - I See Why
Our planet uses many of the same tricks that over-heated humans use to cool off. Our circulatory system is like the great ocean currents moving our excess heat to cooler places. We mist and fan ourselves, put on a white shirt and white broad-brimmed hat, or we head for the shade.

Likewise, Earth wears a white broad-brimmed polar cap that reflects radiant energy instead of absorbing it. Its raft of floating clouds create shade and its winds carry heat in the form of evaporated water away to cooler places. Same-same.

Along with the hydrosphere and lithosphere and atmosphere, we also have a region of Earth called the cryosphere that is dominated by ice. It's a relatively new term in our common language, but it's understanding is important as we learn more about the separate, but connected variables influencing climate on Earth.

It seems Earth's icy poles provide the very desirable function of disposing excess planetary heat absorbed at lower latitudes. Because, as we learned in previous modules, heat moves from where it's hot, to where it's not.

See Ice - Sea Ice
If you live in Alaska near both fresh water and the ocean, you may have noticed each winter that the lakes freeze before the sea does, if it does at all. So, it won't surprise you to hear it takes a pretty cold climate to absorb enough heat from our salty Arctic ocean to force it to surrender to freezing.

Though fresh water reaches maximum density and begins to freeze at approximately +4 Celsius, salty sea surface temperatures must dip to around -3 Celsius before it can begin to form the hydrogen bonds that make it a solid.

Curiously, even at extremely low temperatures, ice still doesn't associate well with salt. The sea water excludes most of the salt ions as it freezes, forcing them out into the water just below the forming ice.

You probably remember earlier we discussed how such super-cooled, super-saline water has the distinction of also being the densest water in the ocean, and therefore sinks in the polar regions to create deep ocean bottom currents - a process called thermohaline circulation.

Strange though it seems, freezing water also gives off heat. Since salt water freezes at a lower temperature than fresh water, it must, therefore, surrender even more thermal energy than fresh water does to its surrounding environment - the even colder atmosphere.

Taken on a large scale, this flux of thermal energy caused by the phase change from liquid to solid water is just one more important method the Earth uses to move heat from where it's hot to where it's not.


EXPLORE

Teachers Domain
Let's explore some more cool science by chilling-out with some TD resources.

Earth's Cryosphere: The Arctic





Arctic Climate System





How the Arctic Ecosystem Might Change

EXPLAIN

• How does the Arctic Ocean influence climate elsewhere on the planet?
• Why are the affects of climate change more dramatic in the Arctic than lower latitudes?
• Why is the Arctic ecosystem both highly productive, and at the same time fragile?
  
• Why is the marine ecosystem more vulnerable to climate changes?

EXTEND

• What kind of snow and ice data exists for your region?
• Are there elders in your area who have a sense of local snow and ice dynamics?
• How are the different positive feedback loops were mentioned in these TD resources connected?

EVALUATE

• What are the values of integrating local Native knowledge with global scientific studies?
  

Module VIII - Reflecting on Sea-Ice

ENGAGE

Let's return to the image of a white, broad-brimmed hat, our polar cap, if you will. We know that white, reflective surfaces don't absorb as much light energy as dark surfaces; That reflected light energy gets bounced away in another direction.

So, it seems ice does double duty when it comes to cooling our planet; Besides absorbing heat as it melts, ice also reflects light back into space before it can be absorbed and turned into heat,as do clouds and snow and any bright surface. Collectively, this reflectivity is called the Earth's albedo.

Pesky Positive Feedback
Conversely, this scenario also presents another one of those pesky positive feedback loops in nature. As more of the Arctic ice cap melts and recedes, there is less bright white ice to ward off the incoming summer solar radiation. However, the increasingly larger surface area of exposed water readily absorbs the light energy that the ice used to reflect.

As the Arctic Ocean turns more and more light into heat, it warms and melts more ice, which in turn reinforces the heating/melting cycle. And to make matters worse, remember that water has a very high specific heat capacity and can store a lot of heat for a long time, further reinforcing climate change forces.

See Level - Sea Level
Much of the discussion about the affects of climate change centers around the problems associated with sea-level rise and the inundation of low-lying population centers. We are told that as ice in our cold polar regions melts, sea-level increases as the ocean takes up the extra water. True enough--in part.

But there's a good reason why this module on sea ice is addressed separately from the next module on terrestrial ice--or ice on land. As it turns out, the affects of melting ice depends very much on where the ice is located. Read on...


EXPLORE

Try This Trick!
Here's another demonstration in our exciting lab series, Watching Ice Melt!

Slightly overfill a glass container with ice cubes and then add water, just so that it doesn't spill over. Let's call this container the Arctic Ocean. Then watch as the ice melts. What will happen to the sea-level in your glass as the ice melts? What will your students predict?


EXPLAIN

• What effect does melting sea ice have on sea level?
  (Find the quick answer here)
  

EXPLORE SOME MORE...

Try This Trick!
This labs is from our exciting series, Watching the Kettle Boil.

1. Safety First! Electricity, Heat, Glass, Water Hazards
2. Shine a heat lamp or similar light source on two glass containers of room temperature water--one protected by or covered in white paper, and the other wrapped in black paper.
   
3. Record the temperature of the water in each container every minute for 20-30 minutes.
4. Graph the data for both containers on the same graph and compare.
   

EXPLAIN

• What is happening to the light energy in this activity?
  
• What are the roles of absorption and reflection in regulating earth's climate??

EXTEND

• Conduct these activities using Inquiry methods.
• Consider including any graphs or data in your next blog.
  

EVALUATE

• What are the values of these simple labs in teaching climate concepts?
  

EXPLORE SOME MORE...

Teachers Domain
Check out these two excellent TD interactive animations demonstrating the effects of climate change on Arctic sea-ice.

Earth's Albedo and Global Warming






Arctic Sea Ice Observations






NASA
NASA's website hosts some of the best and most current, user-friendly Earth Science resources available. This NASA link summarizes the extent of the 2009 Arctic Sea-Ice, along with other excellent media and related links.

2009 Arctic Sea-Ice







EXPLAIN

• How does ice-albedo positive feedback occur?
• What is the effect of melting sea-ice on sea-level?
• How do scientists track the extent of annual Arctic sea-ice?

EXTEND

• What are some ecological or cultural implications of decreasing sea-ice?

EVALUATE

• What are some of the values of interactive information websites compared to videos?

Module VIII - Phun Physics of Phase Change

Taku Glacier Ice Berg in Stephens Passage near Juneau, AK. Photo C.Good


ENGAGE

Phun Physics of Phase Change - BLAB...
Let's revisit our physics lesson a few modules back when we explored how thermal energy is transferred when water changes phase. However, in this case we are talking about the latent heat of fusion, or heat energy exchange that occurs when freezing or thawing water.

Unlike the latent heat of vaporization of water (540 cal/g), the latent heat of fusion for water comes in around 80 calories per gram.

That is, 1 gram of solid water (ice) at 0 degrees Celsius requires an additional 80 calories of thermal energy to become 1 gram of liquid water at the same temperature. Which is to say, like evaporation, thawing is a cooling process. That's why we put ice in our beverages.

And just like the condensation process described earlier, freezing is a warming process. This may sound strange, but water freezing in the arctic helps to warm the surrounding air as the water releases 80 calories of thermal energy per gram into its immediate environment. Crazy.

EXPLORE

Phun Physics of Phase Change - LABS!
Whats more phun than watching paint dry or grass grow? To thrill even the most bored video game enthusiast in the class, try watching ice melt!

Try This Trick!

1. Safety First! Glass, Heat, Water, Electricity Hazards
2. Partially fill a heat resistant glass container with ice-water.
3. Use a safety thermometer (no mercury) to gently stir the ice-water while pausing to check and record the temperature once a minute for several (5-10) minutes.
4. Now place the vessel on a safe heat source and continue gently stirring and taking the temperature for a few minutes.

Review this graph demonstrating the flow of thermal energy in water as it melts and warms.

Click on Graph to Enlarge












EXPLAIN

• What is happening to the water's temperature as the ice melts?
  
• What is happening to the temperature as the rate of heating increases?
• What happens to the temperature of the water after the ice melts?
• Where is the increased thermal energy you are putting into the container going?

EXTEND

• What does this experiment tell you about the role of ice on Earth and what is likely to happen when all the sea ice melts?

EVALUATE

• How does this simple experiment inform you or your students about the role of sea ice in regulating our planets climate?

EXPLORE SOME MORE...

Try This Trick!

1. Safety First! Glass, Water Hazards
2. Partially fill an appropriate container with ice-water.
3. Use a safety thermometer (no mercury) to gently stir the ice-water while pausing to check and record the temperature once a minute for several (3-5) minutes.
4. Next, slowly add a small quantity of salt to the ice water and continue to record the temperature while gently stirring for a few more minutes.
   

EXPLAIN

• What is happening to the water's temperature as the ice melts before and after adding salt?
  
• How and why does the temperature change?
• How does this lab relate to climate and sea ice?

EXTEND

• What does a graph of this data look like?
• Try making old-fashioned home-made ice-cream to demonstrate the super-cooling affects of salt.

EVALUATE

• How does this simple experiment inform you or your students about the role of sea ice in regulating our planets climate?

Helpful Hint: For a Native American view on related activities, see
Keepers of the Earth: Native American Stories and Environmental Activities for Children, found in Google Books.

Module VIII - Blog It!

Essential Question:
How are Arctic sea-ice, climate and culture all connected?

After you have read and reviewed all resources and completed activities for this module, it's time to Blog It!

3 Questions

1. Explain: What new learning or reflections have you taken from this module?

2. Extend: How might you use this week’ information and resources in your lessons? What other resources can you share?

3. Evaluate: How useful, insightful or relevant are this module’s information and resources?

3 Colleagues

• Whose blogs did you visit this week?
• Did you link to their blog?
• What did you like?

PS, Have you reviewed the Final Project Criteria?

Module VII - Changing Climate Introduction

Essential Question: How is Earth's climate connected to its geological, biological and cultural systems?

Introduction
On Earth, the long and short story of climate is largely a story about the amazing atom, Carbon. In this module, we'll explore the history and roles of this element that is central to our existence, evolution and environment. Then we'll continue by exploring the physics of how our atmosphere interacts with the electromagnetic spectrum to help balance Earth's heat budget.

But first, we'll start by considering some vital cultural connections to our changing climate.

Module VII - Cultural Connections

Essential Question: How is Earth's climate connected to its geological, biological and cultural systems?

ENGAGE

Cultural Connections
While there is still much to learn about the timing and routes of the peopling of the Americas, it's interesting and noteworthy that most human migration into the Americas seems strongly tied to the timing of climate changes.

First - Global cooling lowered sea-level by glaciating the land, exposing terrestrial passages eastward from the Asian continent.

Second- Global warming de-glaciated much of the continent, permitting easier passage on land, though it is probable that some of those who migrated to North America came earlier by skin boat or kayak, migrating along coastal routes.

Whether Inuit or Athapaskan, Yupik or Aleut, Tlingit or Haida, Alaska's indigenous people have generations of experiential knowledge that adds to our collective knowledge of how climate change affects ecosystems, as wells as those who depend on them most directly.

EXPLORE

Teachers' Domain
TD has produced a number of great video resources that highlight the perspectives of various Native groups. Review this TD video, Inuit Observations of Climate Change.


Inuit Observations of Climate Change







Career Connections
In this segment, we return to our regular feature of profiling Alaska Natives who live both ways - practicing western science while keeping their cultural practices alive.

Along with the story of La'ona DeWilde is a TD video reporting on how Alaska Native Teens Help Researchers.


La'ona DeWilde: Environmental Biologist







Alaska Native Teens Help Researchers

Helpful Hint: Here's another excellent resource describing how In indigenous communities in the northeastern peninsula of Alaska, 375 teachers and 5,100 students blend Native traditional knowledge with modern science to prepare for careers that can be conducted from rural areas.

The Arctic Climate Modeling Program. Check it out!

EXPLAIN

• What are some of the affects of climate change experienced by Alaska Natives?
• How does La'ona DeWilde use GIS in her work?

EXTEND

• How could you involve your students in authentic scientific research?
• How could you integrate western scientific knowledge and traditional Native knowledge with your students?

EVALUATE

• How useful are these resources for shining two lights on the same path?
  

Module VII - Creating a Nice Atmosphere

Essential Question: How is Earth's climate connected to its geological, biological and cultural systems?


ENGAGE

Creating a Nice Atmosphere
Soft jazz and candle light may be one way to create a nice atmosphere, but don't imagine anything like that 4 billion years ago when our first atmosphere was forming on Earth. Something more like screaming heavy metal and blast furnaces comes to mind.

The proto-Earth formed from the bits and pieces of an ancient star that went supernova and exploded, spewing forth its periodic table mixture of stellar guts. As these bits of stardust were drawn together by their mutual gravitational attraction, they clumped and grew larger in snowball fashion.

And just as occurs in the present day ocean and atmosphere, the denser materials in the hot, molten Earth settled in the center of the planet while less dense matter was rafted upwards toward the surface. Heat created by enormous pressure, radioactive decay and chemical changes in the interior of the Earth caused gases to erupt from the surface of the slowly cooling planet, much in the manner as they do today from volcanoes, geysers and hydrothermal vents.

The early Earth lacking a protective magnetic shield at the time, lighter gases like Hydrogen and Helium were blow away by the intense solar winds. Those gases with sufficient mass to be captured by Earth's gravity clung to the surface of the planet, creating a dense early atmosphere of water vapor, carbon dioxide and ammonia, among others - greenhouse gases. No free Oxygen yet. Sound nice?

Interestingly, the early Sun forming at the same time was considerably cooler than today, so the clouds of dense greenhouse gases on the early Earth helped to keep the planet warm enough for the spark of life to begin the amazing evolutionary processes that have brought you to reading these words today.

EXPLORE

Teachers 'Domain
Humans aren't the first life form on Earth to change its atmosphere. Let's go back in time when early lifeforms on the planet changed it's atmosphere in this TD video, Life Before Oxygen.

While we're on the topic of the role of microbial metabolism on Earth, check out this TD video on recent Arctic studies relating Soil Microbes and Global Warming.

Life Before Oxygen





Soil Microbes and Global Warming







Helpful Hint: NOVA Part of the PBS collection of high quality educational materials includes NOVA's media on cosmic evolution. Check out NOVA's Origins website for a fascinating collection of digital media for use in your classroom.

Origins






EXPLAIN

• What was Earth's earliest atmosphere like?
• Where did most free Oxygen on Earth come from?
• How did the early atmosphere help to foster the first life on Earth?
• How have microbes affected the composition of Earth's ancient and present atmosphere?
• What is a positive feedback loop?
  

EXTEND

• What other atmospheric variables and processes influence climate?
  

EVALUATE

• What's the utility of any of these resources in your or your students' learning; or how you might use any of them in your final project for this course.