Betsy Youngman

How does snow trap gas?

notes for teachers

Overview:

Snowflakes, how do they form? What makes each one so special? How do snowflakes trap gases from the atmosphere? The lessons in this series are designed to teach students about the special traits and talents of snowflakes. After this study of snow flakes, students should be able to understand the processes by which fluffy new fallen snow becomes glacier ice and in the process traps atmospheric gases. Additionally, during this lesson students will become familiar with making an animation using the program NIH image / Image J. Students may also learn how to scan images and create windows.

Content objectives:

At the conclusion of this lesson students will be able to:

Look at drawings and images of snowflakes and identify the conditions under which they were formed.
Understand the processes by which glacier ice forms and atmospheric gases are trapped

Technology objectives:

At the conclusion of this lesson students will be able to:

Independently use the scanner and export images to a file.
successfully create animations with NIH image
Understand how image dimensions are important when creating animations

Time Frame:

4 - 40 minute class periods

2 periods for the background discussion

2 periods to learn the image processing tools and to apply them

Procedure steps:

Read background articles on snow and ice using this website http://www.its.caltech.edu/~atomic/snowcrystals/. Examine at the images and drawings of snowflakes from the discovery channel activity book. Discuss snow flake features and characteristics. Complete the demonstration - making your own snowflakes from the website on snowflakes (address above) for the class.

For the technology segment of the lesson, students will need a computer with NIH image / Imagej and the image files from the scanning lesson, or image files stored on the network. these images are in the movie below.

Begin by reviewing the image processing techniques needed to make a stack from windows. Student notes have this information.

Once students have created the animation for viewing discuss the implications of stored gases in the snow. Students may want to look at other information on this topic on the web at http://www. glacier.rice.edu.

Background Notes:

Students will have a chance to draw and create snowflakes before the lesson. Snowflake characteristics will be discussed. Additionally, students are learning about glaciers and polar science through these lessons. The images and background information for this lesson are from the book Glacier from the Time-Life series "Planet Earth". Additional information used in this lesson drawn from the following resources: The weather channel's book on climate and weather. The Discovery channel: Weather and Climate A-Z resources for teachers.

Related Activities:

see www.pcds.org/arctic for details and links

Ice crystal structure and size

How do glaciers shape the land?

Polar ice caps and climate change

Where are the worlds glaciers and why?

Ice cores - how do they work? What can they tell us about the past?

What happens when glaciers move?

Images for this lesson.

snow01 - snow 08 (TIFF) files from Glacier book - Planet Earth series Timelife books

snow stack - created from the images

snow to ice movie click here