Module VIII...The Cryosphere: Arctic Sea Ice

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

Explore:

The concept of "albedo" is evident here in Alaska in March (which, by the way is the month that "grinds" on me the most). The sun shines, it is higher in the sky, but the snow just hangs around! The gorgeous sunshine and thermal energy, just reflects off of the snow and goes right back into space...before moving up here I would plant my tomatoes in March!

On a more serious note, I found the TD presentation on "Earth's Cryosphere: The Arctic" revealing as I grew up in the Rocky Mountains of Utah and did not know that permafrost existed there!

I also found the Tom Wagner (NASA) clip to be very informative and plan to integrate that clip into my Geology course under the concept of climate.
This module and most of this course contains many activities that I have used or still use in my physical science, physics and geology courses. It has been a great refresher for me as to the activities that I have left out the last few years, along with providing new ones for the future. The activity involving the black and white container, with the heat lamp, is a classic exercise to show how black (and other dark colored objects) are better absorbers (the reason something is black is because it absorbs all light, thus nothing is reflected) and emitters of infrared radiation (thermal energy).
The animation to the right shows the concept called "Black Body Radiation". It represents a theoretical body that absorbs ALL of the light that enters it, when reality shows us that 100% absorption just does not exist in nature. The link above is worth a closer look if you are a physics teacher...it contains a number of "high level" topics of discussion with graphs that are nicely done!

This animation also helps us to understand what is going within an eye when we see the "deer (or other critter) in the headlights"!

Another important point to bring up with students is the difference between heat, thermal energy and temperature. An school building sized iceberg contains a lot of thermal energy, though the temperature is lower than it's surroundings, which is released to the environment when it melts...melting is a "cooling" process...energy from the environment (80 calories per gram) goes into the melting of the iceberg. The age old question of what has the most thermal energy...a hot cup of coffee or an iceberg is a great starting point for the discussion. One more discussion question is why 2000 degree C sparks from a sparkler don't burn...high in temperature but very low in thermal energy. Heat is a term that is used loosely..."someone turn up the heat"...can't be done, but we can turn up the thermal energy...heat is the transfer of energy due to a temperature difference...touch a hot or cold piece of metal and heat transfer occurs!

I like to use the wood stove as an example when discussing the concept of thermal energy absorption and emission. (It is also a great way to introduce the three forms of thermal energy transfer...conduction, convection and radiation.) Other than stoves that are used as a decoration (like the one on the left), wood stoves are black...inside and out! Two of the same model of stove, give me the black one if I am using it to warm the air in a room!

Explain:

In a previous blog I discussed the phase change chart...so simple to use in a classroom, yet so complex when it is applied to climate. It helps us understand how thermal energy is stored and released through the different seasons, along with how small global temperature increases or decreases can have such a dramatic effect on cultures that live at latitudes near or above the arctic circle. The subsistence lifestyle if these people is such that they need ice at certain times of the year to acquire food and they also need open water at other times for the same purpose.

Extend:

Consider how the lack of sea ice could change the way everyone on the planet lives, let alone those who rely on it! The pictures above are 1979 and 2003 polar ice cap images...quite dramatic difference!

Evaluate:

This module has reminded me of the effects of the loss of sea ice...global ocean rise, difficulty of cultures who use it for hunting/travel is diminished, and overall global temperature increases, and has educated me on the decrease of the salinity of the oceans...for me the question would be "how will that effect the life that exists in the oceans?". We all know how closely we are connected to oceans, from global temperatures to hurricanes, drought, the number of people who live near oceans and make their livelihood there, and more! I suppose the next couple of decades will tell the story!