Frozen Lake Study

| 4th Grade - Adult
| Half Day 3 hrs
| Moderate


Students will examine the ecosystem of Wolf Lake under the ice.  Working in groups, they will explore the lake through holes drilled in the ice, from inside ice houses, and by sampling the ice itself.  Studies will include ice depth and structure, lake bottom structure, plankton sampling, and catch and release fishing opportunities.  One adult monitor from the school must attend the class to assist with activity management.

Class Outline

I. What do you expect?

II. Travel to Wolf Lake

III. How can we study the lake?

A. Ice Safety

B. Tool Introduction

1. Cleaning Hole

2. Ice Depth

3. Temperature

4. Sonar Survey

5. Tip-up Activity

IV. In what ways is Wolf Lake alive?

A. Ice Hole Activities

B. Dark House Activities

1.Fish Decoys

2. Sonar Survey

3. Temperature

4. Plankton Samples

C. Ice Fishing

D. Ice Cutting

1.Cultural Perspective

2. Physics of Ice

V. What is our story of the lake? 

IV. What did we notice?

A. Plankton Viewing

1.Food Pyramid

B. Updates to Paint the Picture

C. Continued Exploration

Concepts and Outcomes


1. Frozen lakes are part of northern Minnesota culture through ice fishing, recreation, or historical ice cutting.

2. A lake that is frozen over is alive even if hidden by ice and snow.

3. Collecting data and making observations and comparisons are processes of knowing.



Upon completion of the Frozen Lake Study class students will be able to:

1.Understand and evaluate safe lake ice conditions.

2. Use a sonar and interpret its readings.

3. Determine the “livability” of the underwater environment in winter.

4. Examine a block of ice and interpret its history.

5. Understand where plankton belong in a food pyramid.

Standards Supported

MN Science Standards Grade Code
Objects have observable properties that can be measured. 4
Standard units are used to measure and describe physical quantities such as weight, temperature, and volume. 5 5-PS1-2, 5-PS1-3
Science is a way of knowing about the natural world, is done by individuals and groups, and is characterized by empirical criteria, logical argument and skeptical review. 5
Scientific inquiry requires identification of assumptions, use of critical and logical thinking, and consideration of alternative explanations. 5
Tools and mathematics help scientists and engineers see more, measure more accurately, and do things that they could not otherwise accomplish. 5
Living things are diverse with many different characteristics that enable them to grow, reproduce and survive. 5
Natural systems have many components that interact to maintain the living system. 5
Humans change environments in ways that can be either beneficial or harmful to themselves and other organisms. 5
Current and emerging technologies have enabled humans to develop and use models to understand and communicate how natural and designed systems work and interact. 6

MN Math Standards Grade Code
Solve real-world and mathematical problems requiring addition and subtraction of decimals, fractions and mixed numbers, including those involving measurement, geometry and data. 5

Next Generation Standards Grade Code
Cause and effect relationships may be used to predict phenomena in natural or designed systems. MS MS-PS1-4
Natural systems include a variety of organisms that interact with one another in several ways. 7
Human activity can change living organisms and ecosystems. 7
Natural and designed systems are made up of components that act within a system and interact with other systems. 9
The interrelationship and interdependence of organisms generate dynamic biological communities in ecosystems. 9
Human activity has consequences on living organisms and ecosystems. 9


Extension Activities

Writing Prompts

How do you know if an ecosystem is healthy based on the plankton sample and fish survey?

Write a letter convincing a friend who lives in Brazil that the Wolf Lake is alive beneath the ice.

How do your daily actions affect the health of lakes and rivers?  What actions can you take within your community to ensure we maintain healthy lakes and rivers?

Additional Resources

Lesson plan on aquatic food chains in the great lakes.  Includes a component about how pollution affects food chains.

Interactive online tool where students can explore carnivores, herbivores and omnivores in food chains.