Sebago Lake sunset with melting ice


Lake Ice out Lessons

Grades: 4-8
Group size: any
Location: Class with internet access


This lesson explores ice out in our Maine Lakes. The Grade 4-6 lessons ask students to describe how ice out affects an animal or plant who lives in a Maine Lake. The 7-8 lessons ask students to graph ice out data and to discuss how we can determine if spring weather is coming sooner in our lakes.

Background -- The Greenhouse Effect & Global Warming

You probably know how a greenhouse works. Glass panels let light from the sun in, but trap the heat inside. But did you know that the Earth's atmosphere acts like a greenhouse? The Earth's atmosphere is all around us. It is the air that we breathe, and it is made up of gases. Gases like carbon dioxide (CO2), methane (CH3) and water vapor (H2O) in the atmosphere are called "greenhouse gases" because they trap heat from the sun. Greenhouse gases in the atmosphere behave much like the glass panes in a greenhouse. Sunlight enters the Earth's atmosphere, passing through the blanket of greenhouse gases. Some of the sun's energy goes back out into space, but a lot of it remains trapped in the atmosphere by the greenhouse gases. When these gases trap heat, it warms up the surface of the earth. This is called the "greenhouse effect." Without the greenhouse effect, the earth would be too cold for life to exist. The greenhouse effect is a good thing, but it’s always possible to have too much of a good thing. Human activities, like driving cars and burning coal and oil, are adding A LOT of greenhouse gases, especially carbon dioxide, to the earth's atmosphere. All those extra greenhouse gases could be making the earth heat up more than it should.

Experiencing Lake Ice-Out Activities

Weather/Monitoring Local Ice-Out

Ice-out is when the winter ice cover on a lake breaks up and leaves the lake for the year.  Recording yearly ice-out dates serves as a good, natural indicator of the average temperature.  It is also a common way of comparing the pace of spring's arrival from year to year. 

  • For information about the science behind ice out read Seasonal Magic: How Ice Out in Lakes Helps Nourish Life.
  • Determining lake ice-out:  Help your students decide upon a local lake to monitor for the ice-out date.  Hold a contest in your classroom for who can guess the correct date for this year's ice-out.  Students can research past ice-out dates by contacting the lake association or searching online for ice-out dates of previous years to help them make an educated guess.  The Maine Bureau of Parks and Lands has a good ice-out page with historical dates of ice-out for some lakes and other related information. Check back with your sources or monitor the status of the lake directly to determine the date of ice-out. The student that guesses closest to the exact date wins the classroom contest. When your class has agreed upon the date of ice-out.
  • Maine Volunteer Monitoring Program - A great site to send your own lakes ice out data and compare data from previous years.

Measuring Temperature/Snow and Ice-Out Activity

Tools needed: A hardwood stake 1x1 or 2x2 inch with a point on the end - 48 inches long (in southern Maine or areas with little or no snow you may be able to use a yard stick or ruler), hammer (optional), recording table/sheet. Thermometer in Fahrenheit (we recommend for safety that you do not use a mercury thermometer.)
Before you get started: With a yard stick or other measuring device at least 36 inches long, mark off 1/2 inch intervals on the stake starting just above the point.
Starting February and every week thereafter, have a student record the temperature outside the school and the snow depth (if there is any) at the same time each week.
(1) Measuring temperature:  Have the students choose a shady spot around the school at least 100 feet from the building.  Hold the thermometer at arm’s length (or you could put a small hook on the snow measuring stake).  The goal is to try to minimize the influence body heat or the sun may have on the temperature.   After waiting at least a minute, read the thermometer as quickly as possible.   Do not touch or breathe on the thermometer.  Make sure that their eyes are level with the top of the alcohol column; otherwise the reading will be too high or too low.  Students should record the temperature either in their journals or on their data sheet.
(2) To measure snow depth students should pick a site where the snow is undisturbed (no one has walked, plowed ...), in the open, away from trees and buildings and fairly level - and avoid south facing slopes. (Try to avoid things that would influence snow depth.) Take the hardwood stake (or yard stick) and drive it through the snow. The goal is to get just the point into the earth. Students should read the snow depth off the marks made on the stake. After removing the stake have students check to be sure that the stake was not driven farther than the point into the earth. If it has been they will need to subtract the amount of the stake that was in the earth from their measurement.  Students should record their results in their journal or on their data sheet.

Additional Learning Opportunities

Other suggested learning opportunities for the data include
(1) Graph weekly temperatures from your school or other schools around the state.   Figure the average daily temperature for the state for each week and graph it.
(2) Graph weekly snow depths from your school or other schools around the state. 
(3) You may wish each student to keep his or her own journal of spring: recording robins, frogs, tulips and forsythia blooming, the ice out of a local pond, the temperature at their house when they get up, when they first mow the lawn, or the daytime high temperature picked out of a local newspaper or the nightly news. They may also wish to record any activities they see happening around town that have a positive or negative impact on frogs and robins (i.e. new development, roads, filling wetlands, clearing of trees).
(4) While you are studying how spring is springing in Maine you can submit your data to the to the national monitoring site, Journey North. This way, you can see what happens both here in Maine and across the country.

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