Ice Cream Model -- How Glaciers Formed the Minnesota Landscape
In this classroom demonstration, with the use of ice cream, students will observe the effects that the glaciers had on Minnesota's landscape. After receiving some information on what a glacier is and areas that glaciers have impacted, students will view this teacher demonstration. The ice cream glacier will be moved across a rectangular jellyroll pan as information about the Minnesota glacier movement is reviewed. To represent glacial till, other food items will be added as the glacier story is told (chocolate chips, M&Ms, crushed Oreos, peanuts). When the story and demonstration are completed, the students can enjoy eating the ice cream glacier.
- Students will diagram and label a glacier in their science notebooks (using correct vocabulary such as esker, moraine, drumlin, etc.).
- Students will observe the movement of a small-scale model of a glacier.
- Students will write one paragraph about the ice cream glacier (using the model to describe how glaciers impacted Minnesota).
- Glaciers moved across Minnesota thousands of years ago.
- Glaciers created landforms and moved rocks.
- Glaciers helped form the many lakes and rivers.
Context for Use
The demonstration should be done with your group up close for all to see. Regular classroom size or smaller would be best. Follow the activity description script to guide you through the demonstration.
-Jellyroll pan (to represent Minnesota)
-½ gallon carton of chocolate swirl vanilla ice cream
-Chocolate chips or other food ideas
-Spoons for each student
Resource Type: Activities:Classroom Activity:Short Activity:Demonstration
Grade Level: Intermediate (3-5)
Description and Teaching Materials
Chocolate swirl vanilla ice cream
peanuts (be aware of peanut allergies)
jellyroll baking sheet
small bowls and spoons for each student
large spoon, plastic gloves.
- Explain to the group that we will be creating a model of a glacier much like the ones that covered Minnesota at times.
- Put on gloves and remove the ice cream from the container and put it on the pan. The ice cream is our glacier. Show the students the marbling in the ice cream and explain that as the glacier moves it picks up glacial till and becomes streaked with dirt and rocks. The swirls in the ice cream represent that dirt. Also put some "glacial till" (cookies, M&Ms, and peanuts) under the ice cream glacier.
- Add the rest of the crushed cookies, chocolate chips, peanuts, etc. on the baking sheet. These cookies, etc. represent glacial till (materials such as rocks and soil that are picked up and moved by the force of the glacier).
- Use the large spoon to move the ice cream on the baking sheet. Ask the students to observe what happens as the glacier encounters the till. It can stick to the glacier, be pushed along in front of the glacier, or be pushed off to the sides. There will be scratches or striations when the glacier pulls the till it carries or as it retreats. Explain that pressure compacts the glacier naturally due to snowfall, and ice buildup. This process takes thousands of years in nature. As you give information about Minnesota glacial movement, move the ice cream to the appropriate areas of the Minnesota jellyroll pan.
- In order to see how glaciers moved or "oozed", have students rub their hands together and feel the heat created by the friction.
- Ask for questions . . .
- Eat the glacier and enjoy!
Below are more information and a more complete script of this ice cream activity:
The "Ice Cream Glacier" activity would probably be better understood if the students have had some background information about glaciers (definition, vocabulary, diagram).
To introduce this demonstration, ask if anybody has been on a glacier or has ever seen a glacier. Are there still real glaciers that people can see? Well, today we are all going to have the opportunity to see one right before our very eyes! You will see it move, you will see it pick up soil and even pick up rocks of various kinds. Well, we are not leaving Minnesota so do you think we can make this happen? Do you think Minnesota ever had glaciers? Well, if it were at all possible for our whole class to see a real glacier up close that would be best. But since it isn't, I am going to just show you a model of a glacier moving across Minnesota. We had said there are no longer glaciers moving across Minnesota, but I will show you with this model where the glaciers moved and how the glaciers changed Minnesota.
Today, it is hard for us to imagine the size and power of a glacier. In an attempt to better understand that process, we can create this model or mini glacier. To start out with, this is a model of Minnesota. (hold up jellyroll pan - the true shape of Minnesota could be attached behind the pan to give it a "more like Minnesota look") Now for the glacier - (unwrap the ice cream from its carton so it is in one big chunk) why do you think I chose this particular ice cream - chocolate swirl vanilla? (white for snow and ice / choc swirls for dirt and soil picked up by the glacier) I am going to place this glacier on Minnesota while we go over a bit of Minnesota glacier history. I am also going to add some "glacial till" (cookies, M&Ms, and peanuts) under this ice cream glacier before we start.
Now, how long ago were glaciers in Minnesota? (2 million - 10,000 years ago) Minnesota saw the advance and retreat of several major glaciers during that time. What is a glacier? A glacier is a large body of ice moving slowly across a land surface. It forms when snow accumulates faster than it melts over a long period of time. Under the weight of the ice mass, a sole of ice melts at the bottom and allows the glacier to move. The gigantic Laurentide Ice Sheet, centered in what is now Hudson Bay. (show area on a map) This ice sheet grew and retreated depending on the climate change during a time called the Ice Age. When it was during a colder period, it extended down into our area. There were names given to these glaciations depending on what area they moved into - Nebraskan, Kansan, Illinois, and Wisconsin. The glacial ice, possibly one mile thick in places, scoured the bedrock in northeastern Minnesota, scooped out the basins for the Great Lakes, eroded a mighty mountain range, and carved the bed for Glacial Lake Agassiz, an ancient lake so large its area could contain all of the Great Lakes rolled into one. Enormous amounts of water were released as the glaciers melted, forming large glacial lakes. The largest of these lakes was Lake Agassiz, which covered the Northwestern part of the state 9,000 to 12,000 years ago and dipped down into the Red River Valley. The latest (or last) one in the area was the Wisconsin glaciations, which left our state of Minnesota with the landforms, lakes, and rivers that we have today.
Beginning about 75,000 years ago, it, too, experienced periodic growth and decay with changing conditions. Its advances produced tongues of ice called lobes, each named for a specific geographic area: Wadena, Rainy, Superior, and Des Moines. Each lobe also experienced periodic growth and decay.
- The Wadena Lobe advanced from the north several times. Its last advance deposited the Alexandria moraine (which was later reglaciated), the Itasca moraine, and the drumlin fields spanning Otter Tail, Wadena, and Todd counties.
- The Rainy and Superior Lobes came out of the northeast and advanced, sometimes with and sometimes independently of the Wadena. Its last advance left a coarse-textured till of basalts, gabbro, granite, iron formation, red sandstone, slate, and greenstone strewn across the northeastern half of Minnesota and as far south as the Twin Cities.
- The Des Moines Lobe originated in the northwest and advanced in a southeasterly direction across Minnesota and into Iowa. Its fine-textured till consisted of limestone, shale, and granite fragments, from which developed the fine prairie (now agricultural) soils found in these areas.
Earlier lobes and glaciations also left their marks, though their effects are generally buried beneath more recent glacial drift. We occasionally glimpse the underlying till that is distinctive of their origin, or the striations on bedrock outcrops that indicate their direction of travel. When the glaciers moved, they picked up rocks and soil from the land below. Use the large spoon to move the ice cream on the baking sheet. Ask the students to observe what happens as the glacier encounters the till. It can stick to the glacier, be pushed along in front of the glacier, or be pushed off to the sides. There will be scratches or striations when the glacier pulls the till it carries or as it retreats. Explain that pressure compacts the glacier naturally due to snowfall, and ice buildup. This process takes thousands of years in nature. As you give information about Minnesota glacial movement, move the ice cream to the appropriate areas of the Minnesota jellyroll pan. (see map diagrams (attached)).
Glaciers sculpt the surface of the earth as they expand, cutting through relatively soft materials, picking up occasional pieces of rock or debris along the way, and depositing them further on. As the sole picks up various sizes of debris, it acquires texture and abrasive power that varies much like grades of sandpaper. On some bedrock outcrops today, parallel lines scar the surface, indicating that a rock frozen into the glacier's sole passed here long ago. These markings are called striations, while wider, deeper markings are known as grooves. Finely textured particles in the sole produced highly polished rock surfaces, much like fine sandpaper. Striations and grooves are helpful in identifying the direction of the glacial flow that took place on a given site. The retreat of glaciers left behind the rocks and soil that it had picked up in other locations. An excellent example of glaciers depositing rocks in an area when are not typically found, is the "the Three Maidens" near Pipestone, Minnesota. These are three very large granite boulders that are not from that area.
As the glacier began to melt, it needed an outlet for the melt water. As natural dams of Lake Agassiz gave way, it spilled out over its banks and began draining south. This outlet in Minnesota is known as the Glacial River Warren and is basically the same channel used by the Minnesota River today. River Warren's channel was much wider than the Minnesota River is today. It was up to 3 miles wide and 200 feet deep. River Warren had a huge impact on the geologic design of the state of Minnesota. Another outlet of the Glacial River Warren later spilled into Lake Superior.
Glaciers, which covered the state, also created many other rivers in Minnesota thousands of years ago. As the ice melted, it formed many of the river channels that we have today such as: the Red, Rainy, St. Louis, Minnesota, and other rivers and streams in Minnesota. It is interesting to look around Minnesota and to now understand how some of the landforms and bodies of water came to be. [file 'Entire MnSTEP Earth Science Activity (Word Document)'] [file 'Glacier Maps']
Teaching Notes and Tips
-Save much of your information and discussion after the ice cream is placed on the pan to allow for some "melting and moving" of the ice cream glacier.
This activity has been presented before to my 4th graders, but a guest presenter demonstrated it. After taking the Elementary Earth Science class, and with the addition of this activity's background information, I would be comfortable to present this activity to my class on my own.
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