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There Goes an Animal’s Biological Clock


Children are curious about their environment, but generally are not able to independently make connections regarding their observations. This mini-unit adapted from Journey North’s spring program, will help second grade students to understand the seasonal changes that occur during the weeks immediately preceding and following the onset of  autumn. Be sure to start this project on or before the first week of September.

Summary: Students will collect and interpret photoperiod (the amount of daylight hours) and isotherm (average weekly temperature) data for their immediate area. The compiled data and student environmental observations will enable children to discover the effect our sun has on the migration of monarchs and robins. The activity can be extended to plants by recording the first killing frost and its effect on the trees and smaller plants in their area.

Word Wall Words: a.m., autumn, average, isotherm, migration, p.m., photoperiod, temperature, thermometer


    1. Students will calculate daily average temperatures and weekly isotherms.
    2. Students will calculate daily suntimes.
    3. Students will interpret and analyze data collected.
    4. Students will correctly identify monarch butterflies and robins.
    5. Students will record their animal sightings in a class/individual journal.
    6. Students will make predictions throughout the project that can be collaborated with future data.
    7. Students will discover the effect the sun has on our environment and animal migrations.
    8. Students will gain the understanding that migrating animals use internal timing mechanisms known as "biological clocks" to tell time.
    9. Students will accurately collect and record project data.

Mini-Unit Activities:

      Prior to onset of this activity the teacher should create a table on lined chart paper (or computer) with the following headings: date, high temperature, low temperature, daily average, and weekly isotherm. Always start each week with Sunday and record the weekly isotherm temperature only on Saturdays.


    High Temperature

    Low Temperature

    Daily Average Temperature

    Weekly Isotherm

    Sun., 7/4

    95* F.

    67* F.

    81* F.


    Mon., 7/5

    97* F.

    71* F.

    84* F.

  1. Discuss the meanings of temperature, thermometer, isotherm, and average with the students. Place the words and their definitions on the Word Wall.
  2. Teach a math lesson on averaging utilizing a manipulative such as Unifix cubes. Using a cube to represent each student having a birthday in a specific month such as August, direct students to build a tower of cubes representing the number of August birthdays in your room. Build another tower for a second month, such as September. Pose the question: How many birthdays would we have in August and September if there was the same number each month? Emphasize the average number of birthdays in August and September is ____. Try additional problems finding the average of class birthdays for other sets of two or three months. After students understand the concept of finding averages with small numbers using the cubes, direct students to find the average of 68 and 84. This last one leads to using a calculator to find averages of larger numbers. Children will want to check out the problem with both their Unifix cubes and calculators to be sure that the average of 68 and 84 really is 76. Continue with similar problems until you feel students understand that averaging means you add the two (or more) numbers together and divide that sum by two (or more). The resulting answer will be their daily average temperature to be recorded on their isotherm chart. This lesson will also allow children to discover decimals on the calculator and rounding. You many want to allow more than one class period for this exploratory math lesson!
  3. Using a classroom thermometer that records daily high and low temperatures or a local newspaper, record daily data on the isotherm chart. Calculate and record the daily average temperature.
  4. Each Monday calculate the isotherm for the preceding week. Direct students to add the daily average temperatures and divide by the seven days. Record the weekly isotherm temperature on Saturday’s row of data.
  5. Teacher Note:Some people believe that robins migrate north as the isotherm reaches 36 degrees Fahrenheit. Is the reverse true? Do robins migrate south in the fall when the isotherm in their area is lowered to 36 degrees? At what isotherm temperature do monarch butterflies leave your area? With your students try to discover what has changed in your environment that causes these animals to migrate when they do.

Teachers will find the background information on the above web page informative, but students and teachers alike will enjoy completing Activity A. As an extension of this mini-unit, have students complete Activity B for a future reference throughout the school year.

      Prior to onset on this activity the teacher should develop a table on lined chart paper (or computer) with the following headings: date, sunrise, sunset, and daily suntime. Always start each week with Sunday.




    Daily Suntime

    Sun., 7/4

    5:52 a.m.

    8:59 p.m.

    15 hrs. 7 min.

    Mon., 7/5

    5:53 a.m.

    8:59 p.m.

    15 hrs. 6 min.

  1. Discuss the meanings of photoperiod, a.m., p.m., autumn, and migration with the students. Place these words and their definitions on the Word Wall.
  2. As teams, then as individuals, have students access the U.S. Naval Observatory’s Internet web site to determine their local sunrise and sunset times or discover that information in their local newspaper. Record the sunrise and sunset times on the chart.
  3. During a math class period provide students with individual clock dials. Introduce an elapsed time lesson with simple problems (i.e. How many hours and minutes have passed from 3:00 a.m. to 6:15 a.m.). Then provide the challenge problem for students to solve either individually or in teams – How many hours and minutes will the sun be shining in our area from sunrise to sunset today?

Most students in kindergarten and first grade have learned that sunlight is one of the components plants need to grow and make their own food. They have also learned about specific animals eating plants (i.e. cows eating grass). Many second graders have not stopped to realize that food chains alter as seasons change. The cow still eats grass in winter, but it is hay that has been stored by the farmer during the summer growing season. What happens to wild animals living in your area that depend upon plants for their food? Are there changes in a specific plant that causes the monarch butterfly to leave your area? As children complete this activity they may start asking their own questions.

Students may want to investigate some of the following web sites to better understand and identify monarch butterflies and American robins.






http://www.netaxs.com/~mhmyers/cdjpgs/robin2.jpg (picture)



Students have participated as a collaborative member in completing the class tables by recording weekly isotherms and daily photoperiod times. To further assist them in learning the skill of independently interpreting data, direct each student to start an Autumn Reflections Journal with weekly reports gathered from the data recorded in the two tables. During the first two or three weeks, collaboratively write the responses. Encourage students to do sections of the report independently or in teams when you feel they are ready.

Write an entry every Monday recording the isotherm data collected during the previous week and the photoperiod time for Saturday of that same week. Students will then be able to interpret the data with their previous entries or make observations of the changes during that specific week. Sentences can be written documenting the decrease in the isotherm temperatures and decrease in the photoperiod times. An observation sentence and a prediction sentence can also be added. Observations would include changes in the plant and animal life in their environment. Predictions might include when they think the monarch butterflies will leave their area, the leaves will start to fall from a tree located on the school grounds, the isotherm will reach 36 degrees Fahrenheit, or what day this school year will the photoperiod be exactly 12 hours. Always stretch the child’s critical thinking and reasoning skills by asking him/her to add an answer to "Why?" he/she made a specific prediction.

Students will have a greater awareness of the changes that occur as seasons change if they can readily refer back to their earlier recorded data.



This mini-unit project was created for second graders by educator Judy Christiansen.

All of the activities included have been successfully used in Mrs. Christiansen’s classroom.