Lesson E7: Glaciers and Icefields

Key Ideas     Unit Checklist

  Video Lesson

How do glaciers create landscapes? Watch this video to learn more about glaciers and icefields.

 
 

  Lesson E7: Glaciers and Icefields


Figure E.2.7.1 – In the past, ice sheets covered large parts of Earth.

Figure E.2.7.2 – A melting ice sheet left behind the “Big Rock” in Okotoks.


Figure E.2.7.3 – Retreating glaciers leave behind long, low hills called drumlins.
Reading and Materials for This Lesson

Science in Action 8
Reading: Pages 363–365

Materials:
Empty and clean paper milk carton (1 L), sharp scissors, water, freezer, 10 rocks (1–2 cm diameter), sand, play dough, deep baking pan (9x13 inches), mittens or gloves, borax (1 tbsp), 250 mL Elmer’s Glue™ (white glue), measuring cup, measuring spoons, plastic cup, 2 plastic spoons, large aluminum foil pan, rubber gloves, paper towel, ground black pepper, book (3 cm thickness).

Ice Ages

Earth’s average temperature has fluctuated over time. When Earth has a lower average temperature, large glaciers form and cover large areas of land. An ice age is a time period when these large continental ice sheets are present on Earth.

Because continental ice sheets cover Greenland and Antarctica, we are still in an ice age. Warm and cool periods exist within ice ages. We are currently in a warmer interglacial period. A cooler period during an ice age is called a glaciation.

Earth’s last glaciation ended 10 000 years ago. During this glaciation, all of Canada was covered by a massive glacier. As this continental ice sheet melted and retreated, it created many landscapes across Canada. For example, erratics are huge rocks that can be found scattered across prairie fields. Erratics were moved by ice sheets and left behind as the glaciers melted. Another glacial landform is long, low drumlin hills, which are made from deposits of glacial till.

 Watch More

How Glaciers Change the Landscape

Watch this video to learn more about how glaciers erode and shape landscapes.

 
 

  Try It! 

Figure E.2.7.4 – Glaciers leave behind landform clues like erratics.
Glacial Landforms

Try this simple activity to understand how glaciers create landscapes. 

Materials: 
  • Empty and clean paper milk carton (1 L)
  • Sharp scissors
  • Water
  • Freezer
  • 10 rocks (1–2 cm diameter)
  • Sand
  • Play dough (can purchase or make with this recipe)
  • Deep baking pan (13x9 inches, 33x23 cm)
  • Mittens or gloves


Take care with scissors; don't cut yourself or anyone else!
Instructions:

  1. Cut off the milk carton’s pointed top. Make the cut halfway down the milk carton, so you are left with a cube-shaped box.

  2. Place 10 rocks in a single layer in the bottom of the milk carton.

  3. Place a layer of sand on top of the rocks. Add just enough sand to completely cover the rocks.

  4. Slowly pour water over the sand and rocks. Pour carefully so that you don’t disturb the placement of the sand and rocks. Add water to a height of 4 cm above the sand.

  5. Put the milk carton into the freezer for at least 12 hours.

  6. Fill the deep baking pan with a 5 cm layer of play dough. Press the play dough firmly onto the bottom of the pan.

  7. Put on your mittens or gloves.

  8. Take the frozen milk carton out of the freezer. Peel the paper off the milk carton, so you are left with an ice block.

  9. Place the ice block, rock side down, on the play dough at one end of the pan.

  10. Push the ice block across the play dough, all the way to the other side of the pan. What do you observe on the surface of the playdough?

  11. Leave the ice block in the middle of the pan. Place the pan in a warm spot and let the ice block melt over several hours. What do you observe?

  12. Watch this video to see this a similar experiment and its results:

 
 
Questions: 

Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.

Figure E.2.7.5 – Long scratches, called striations, were left behind as glaciers scraped by.
Figure E.2.7.6 – These erratics are sitting on hills of stones called kames.

In this experiment, you observed that rocks in the ice block scratched out grooves in the play dough. Moving glaciers erode underlying rock. As glaciers move, pieces of eroded rock travel underneath. These eroded rocks scrape against the underlying rock surface, making long scratches or grooves.
In this experiment, when the ice block melted, it left behind rocks that were under the ice block. This represented how a melting glacier leaves behind erratics. The melting ice block also left behind a sand hill. This represented how a melting glacier leaves behind small kame hills of glacial till.

  Try It! 

Flowing Glaciers

Try this simple experiment to observe glacier movement.

Materials: 
  • Borax (15 ml or 1 tablespoon)
  • Water
  • 250 mL Elmer’s Glue™ (white glue)
  • Measuring cup
  • Measuring spoons
  • Plastic cup
  • 2 plastic spoons
  • Large aluminum foil pan
  • Rubber gloves
  • Paper towel
  • Sand
  • Ground black pepper
  • Book (3 cm thickness)

Instructions:

Watch this video to see how to make a simulated glacier, then follow the instructions below to make your own and observe its flow:

 

 

  1. Pour all the white glue (250 ml) into the foil pan.

  2. Add 300 ml (1 cup) of water to the foil pan. Stir with a clean plastic spoon to thoroughly mix the glue and water.

  3. Measure 35 ml  (â…› cup) of water into the plastic cup.

  4. Add 15 ml (1 tablespoon) of borax to the plastic cup and stir with a clean plastic spoon to dissolve. Some of the borax might not dissolve completely, which is OK.

  5. Add 1 spoonful of the borax solution to the foil pan. Thoroughly mix the borax solution into the glue and water mixture.

  6. Put on rubber gloves. Squeeze and knead the dough into a thick oval shape.

  7. If necessary, add more water or borax solution until the mixture has the consistency of a very sticky dough. Be careful not to add too much borax, otherwise the mixture will become crumbly instead of sticky.

  8. Rinse and dry the foil pan with paper towel.

  9. Sprinkle some sand and black pepper on one end of the foil pan.

  10. Place the dough at the other end of the foil pan.

  11. Lift the dough end of the foil pan slightly, about 3 to 4 cm. Put a book underneath to tilt the pan.

  12. Observe the dough in the pan for several minutes. What happens as the dough comes into contact with the sand and black pepper?

Questions: 

Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.


The dough flowed downhill very slowly, just like glaciers flow very slowly.
The sand and black pepper were pushed along the edges of the dough. This represented the formation of moraines, which are deposits of glacial till along the sides and front edge of glaciers.
Figure E.2.7.7 – Hollow drills extract long ice core cylinders.
Figure E.2.7.8 – Scientists obtain ice core samples from continental ice sheets.


Figure E.2.7.9 – Several ice cores are used to verify observations and compare results.
Information From Ice

Greenland and Antarctica are covered in thick continental ice sheets. When global climate is cold enough, new falling snow does not melt, burying and compressing older layers of snow into ice. These ice layers build up over thousands of years. Some continental ice sheets are two kilometers thick!

Scientists use ice core samples to find out information about Earth thousands of years ago. Ice cores are long ice cylinders drilled from continental ice sheets. A hollow tube drill removes an ice core sample.

As snow falls and compresses into ice, it traps atmospheric dust and gases. Analyzing the air trapped in ice core layers gives scientists information about how Earth’s atmosphere has changed over time. They have found that higher levels of carbon dioxide in ice core samples match warmer periods in Earth’s history.

The water particles in ice cores provide information about the average temperature on Earth. Water particles have two slightly different forms, called isotopes. One type of water isotope is slightly heavier than the other. When Earth has colder average temperatures, more of the lighter water isotope falls as rain and snow.  When Earth has warmer average temperatures, more of the heavier water isotope falls as rain and snow. By measuring the amounts of light and heavy water isotopes in ice core layers, scientists can determine changes in Earth’s average temperature over time.

Figure E.2.7.10 – Scientists analyze the water and air in ice cores.
Figure E.2.7.11 – Ice cores are examined visually and tested chemically. Photo courtesy Oregon State University.

 Watch More

Ice Core Samples

Watch this video to learn more about ice core samples.

 
 


Climate Change and Glaciers

Earth’s average temperature has risen quickly over the last 200 years. Scientists agree that this rapid temperature increase is a result of humans burning fossil fuels, which creates heat-trapping carbon dioxide. This process is described as global warming, or climate change.

 
Click here to Explore with Elsie about the effects of climate change on glaciers.



  Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to guide your learning.

Unit E Lesson 7 Self-Check

Instructions


Complete the following 6 steps. Don't skip steps – if you do them in order, you will confirm your understanding of this lesson and create a study bank for the future.

  1. DOWNLOAD the self-check quiz by clicking here.

  2. ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.

  3. COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.

  4. REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.

  5. SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.

  6. CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum, or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!

Be a Self-Check

Superhero!



Self-Check Quiz Answers

Click each of the suggested answers below, and carefully compare your answers to the suggested answers.

If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.

Alberta contains glacial landforms such as erratics, drumlins, and kames, showing that it was once covered by an ice sheet. The rocks in these glacial formations have a different composition than the surrounding underlying rock, which is why we know they came from glaciers.
Glaciers erode underlying rock. Pieces of eroded rock move with glaciers. The rocks carried by a moving glacier scrape away at the underlying rock, leaving behind striation scratches.
Many of Alberta’s rivers flow out of mountain glaciers. These rivers are a main source of drinking and agricultural water for Albertans. If mountain glaciers completely melt, there will be a shortage of water to meet the needs of people in Alberta.
Melting continental ice sheets add water to the oceans. This causes sea levels to rise. Rising sea levels will flood low-lying areas in coastal communities, making these areas uninhabitable.
Mountain glaciers have a thin film of water underneath, making them move much faster than continental ice sheets. Faster moving glaciers cause more erosion. The faster moving mountain glaciers of the Rocky Mountains erode rock faster than the slow moving ice sheet glaciers of Antarctica.