Oklahoma Ag in the Classroom

December Page

Winter Solstice

In the Northern hemisphere, the shortest day and longest night of the year falls on December 22. Solstice means "standing-still-sun." Winter solstice occurs when, because of the earth's tilt, our hemisphere is leaning farthest away from the sun; therefore, the daylight is the shortest and the sun has its lowest arc in the sky. Winter solstice in Oklahoma occurs at 11:30 pm on December 21.

Since ancient times people have kept track of the length of days so they could understand where they were in the year. On the shortest day they knew that winter was halfway over. Understanding the time of year was very important to ancient farmers, just as it is to farmers today. Seeds needed to be planted at the right time. Crops from seed sown too early would be destroyed by bad weather. Crops planted too late would not have time to mature for harvest.

Today Oklahoma farmers have very sophisticated tools for tracking length of days, soil temperature and moisture, rainfall and many other factors to help determine exactly the best time to plant, fertilize, etc. Oklahoma Mesonet provides volumes of useful information to Oklahoma farmers on its AgWeather site.

Solstice Activities

• Sunrise/Sunset lesson from Oklahoma Mesonet: The length of the day and the total incoming solar radiation on a clear day are directly related to the time of the year and a location's latitude. Using a graph of Mesonet daily solar radiation, students will determine the times of sunrise and the length of day.
• Lead a discussion about the length of days. Have students noticed there are activities they are no longer able to do in the evenings? Have they noticed it is darker outside when they wait for the bus in the morning?

Writing Prompts

• Keep a journal for the month of December showing how the length of days affects your activities.
• Pretend you are an ancient farmer on the shortest day of the year. What are your thoughts?

Books

Branley, Franklin M., Sunshine Makes the Seasons, Collins, 2005. (Grades 1-4)

An excellent resource for explaining the concept of seasons, using a pencil and orange and focusing on the sun-earth relationship.

McKneally, Ranida, and Grace Lin, Our Seasons, Charlesbridge, 2007. ) Grades K-5)

Haiku poetry accompanies season-related questions and answers about weather, the natural world and the human body.

Paulsen, Gary, Winter Room, Scholastic, 2009. (Grades 4-7)

The winter room is where Eldon, his brother Wayne, old Uncle David, and the rest of the family gather on icy cold nights, sitting in front of the stove. There the boys listen eagerly to all of Uncle David's tales of superheroes. Then one night Uncle David tells the story, "The Woodcutter," and what happens next is terrible - then wonderful.

 

Background photo courtesy Oklahoma State University

December Page

Oklahoma Ag in the Classroom

Oklahoma Ag in the Classroom is a program of the Oklahoma Cooperative Extension Service, the Oklahoma Department of Agriculture, Food and Forestry and the Oklahoma State Department of Education.