Virtual Exploration #1
How are Glaciers Formed?

This image was taken by Matthew Durant 
at Wrangell St. Elias National Park.

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How are Glaciers Formed?




Text Message #2: 

From: Crystal
Subject:  Your Tasks

Time is running short!!!  It is very important that you and your team embark on the Virtual Exploration.  You'll be traveling to the Worthington Glacier which is in the Chugach Mountains, in South Central Alaska. We'll be in glacier country and will have a great opportunity to explore how glaciers are formed.  Hurry, we must leave right away.

We will:

  1. Embark on our Virtual Exploration #1: How are Glaciers Formed? 

  2. Use the Online resources to learn more about how glaciers are formed.

  3. Get Hands-On:  Conduct a scientific experiment where you will apply the knowledge of glaciers that you have gained.

  4. Use the "Spy Kids" assessment guide, to see how you are doing.

  Good Luck!!!



I want to embark on Virtual Exploration #1




Virtual Exploration #1
How are Glaciers Formed? 

Worthington Glacier 
in the Chugach Mountains

Snow, snow, and still more snow pile up to create these massive, flowing rivers of ice.  If the amount of snow that falls in the winter is greater than the amount of snow that melts off in the summer, then snow begins to accumulate from year to year.  The pressure of the accumulating snow builds, transforming the snowflakes into firn and eventually the firn into glacier ice.  All of this snow will gradually spill over the side and begin to flow downhill.  A glacier is born!



October 2003

A single snowflake falls towards the ground.  Then another, and another, and still another...  Once there, these flakes join the billions of other snowflakes that have already fallen.  It's only October but already the snow is accumulating. 

Each snowflake is light and fluffy and made up of over 90% air.  Make a snowball.  Go on, make one.  In that one snowball there are over 50 million snow crystals.  

Here, I brought a case (about the size of a suitcase) to collect a sample. Please, fill it with this fresh snow and bring it over here. Don't worry because the snow is so light and full of air, it will only weigh about as much as a 2-year-old.




November 2003

Wow, that snow is really beginning to pile up.  It's getting deeper and deeper. Over the course of this winter, we could get over 700 inches of snow.  Each layer of new snow adds a little weight to the snow below it. It begins pressing down on the snow below and as it packs down, air is pressed out.  Now, there is only about 50% air in the snow.




November 2004

The snow is quickly piling up.  That first snowflake that we saw fall is now buried deep under lots of snow above.  The heavy weight of the snow above is pressing down, squeezing the air out of the snow below.  The weight changes the snowflake into ice with some air trapped inside (about 30% air).  This ice/air mix is called firn. 

Here, I brought a case (about the size of a suitcase) to collect a sample.  Please fill it with the firn.  You may need some help carrying it over.  It's going to be about as heavy as a girl in middle school. 




November 2020

It's been a long, long time since we've been back to this Worthington Glacier.  The snow has really piled up. That tiny snowflake is now buried deep below the surface.  Intense pressure from above this snowflake, turned  firn, has now been squeezed and compacted into the densest ice on Earth, glacier ice. 

Here, I brought a case (about the size of a suitcase) to collect a sample.  Please fill it with the glacier ice.  You may need some help carrying it over.  It's going to be really heavy.  Probably about as heavy as a heavyweight fighter.  That's heavy!




How Do Glaciers Form? Great information with a super chart to explain how a glacier is formed.

The Glacier Story A great slide show of glacial formation.  Good images and information.

How Do Glaciers Form? Good information in a type of a slide show format.

Glacier Formation A great site to learn more about how glaciers form.

Life Cycle of a Glacier Some very good information on a glacier.

Anatomy of a Glacier Good interactive site.  Click on a number to learn more about that part of the glacier.

Snow Crystal Gallery

Good images of snow crystals.

Morphing Snow Flake to Glacier Ice A great QuickTime movie on the morphing of a snowflake to glacier ice.


Ice of All Shapes and Sizes Learn more about all of the vocabulary you have heard so far.



Alaska's Glaciers. Alaska Geographic volume 9, number 1, 1982.

An observer's guide to the glaciers of Prince William Sound, Alaska. Valdez, AK:  Prince William Sound Books,  1987. 

Glacier. R. H. Bailey and the Editors of Time-Life Books Alexandria, VA: Time-Life Books, 1982.

Glaciers  John Gordon.  Stillwater, MN Voyageur Press, 2001.

Glaciers, Natures Frozen Rivers. H. H. Nixon and J. L. Nixon. New York: Dodd, Mead, 1980.

Glaciers of North America: A Field Guide. S. A. Ferguson. Golden, CO: Fulcrum Press, 1992.

Blue Ice in Motion: The Story of Alaska's Glaciers  S. Wiley. Alaska Natural History Assn. 1995.



  1. Discussion: What do you know about how glaciers are formed?

  2. Snowballs and Glaciers:  Who has ever created a snowball?  When you pack the snow that you picked up, it becomes very hard.  With more pressure you can change the snow into an ice ball.  Ok, don't throw ice balls at each other because they really hurt.  This is a very similar process that glaciers go through.   Massive amounts of snow above create enough pressure on the snow below to transform it from snow to firn to glacier ice. 

  3. Make a Mini-glacier:  
    1. To represent land, place dirt and rocks at the bottom of a plastic shoe box.
    2. Cover the soil and rocks with snow from outside or shaved ice that you create by placing broken ice cubes (carefully hammer ice cubes in  a towel) into a food processor. 
    3. To simulate the massive amount of pressure that snow above has on the snow below, place a board with some rocks or a brick on top of the packed snow.
    4. To simulate the cold Alaskan Winter, place the shoebox with packed snow into a freezer overnight.  
    5. The next day, add more snow to your glacier and pack it down with more weight.  Place back into the freezer and freeze overnight.
    6. Repeat step E for several days.
    7. Take your model glacier out of the freezer and remove the board and rocks.  Slightly warm the sides of your plastic container by running it under warm water. Just do this long enough to get the model glacier out of the plastic shoe box when the sides are tapped.

  4. Similarities between your model glacier and an Alaskan glacier: 
    1. Sketch and label your model glacier.  
    2. In a science journal, review how the model glacier you made is similar to the glaciers we have seen in Alaska
    3. With your friends, create a Venn diagram to explore the similarities with your model glacier and a real glacier.

  5. Place your glacier back into the plastic bin and put it back into the freezer.  We will use your model glacier for our next experiment.

 Assessment Guide

Click here to see a rubric to help you assess and revise your own work.


 Revisit the Question

How are Glaciers Formed?


Home    What is a Glacier?    How do Glaciers Form?  
How do Glaciers Move? 
  How do Glaciers Shape the Land?

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