Phenology Data Exchange Using nature's clues, can you find your partner? Helpful WWW Links As you collect information about your site, the following list of WWW links may help you (each link opens a new web browser): Photoperiod Photoperiod is the number of hours between sunrise and sunset. You can look up the sunrise and sunset times for your area on the U.S. Naval Observatory Web site. Normal Daily Maximum Temp Normal Daily Minimum Normal Monthly Precipitation Growing Season: Your "growing season" is defined as the number of days between the LAST frost in Spring and the FIRST frost in the Fall. Look up your growing season by using the frost date location tables and maps provided below: Link to U.S. Frost Date Maps Link to Canada Frost Table Skills for Tracking the Seasons (All the following lessons are optional) Shadow Sticks and the Sun Students measure shadows and explore how they change over the course of a day and over the seasons. When are shadows the longest? The shortest? Why? Reasons for Seasons: Exploring the Astronomy of Spring Many people have misconceptions about why we have seasons. The real reason for seasons lies in the fact that the Earth is tilted on its axis. The tilt of the Earth affects the length of days and also the amount of direct sunlight received during the seasons. Try this lesson before the migrations begin. Seeing The Light: Recognizing the Sun's Role in Living Systems Using a food chain "Webbing Activity", explore how changing photoperiod affects the food chain. Copyright 2001-2004 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form