The ComPADRE Collections

Sun Path: Interactive On-line Mac or PC

Sun Path JAVA applet written by the Australia National University. Starting Point example and page by R.M. MacKay.
This material was originally created for Starting Point:Introductory Geology
and is replicated here as part of the SERC Pedagogic Service.

Summary

The Sun Path JAVA applet uses equations for a spherical Earth to calculate the sunrise and sunset times, the solar azimuth and solar altitude for any time of year and any latitude. The program can be run in yearly, monthly, daily, or hourly modes to create animations of the sun's path across the sky for different conditions and with different time resolutions. Sun Path "... models the Sun's path in a geocentric view, it calculates and visualizes the position of the Sun based on the latitude and the time. It allows to simulate the Sun's position and path during an hour, a day, a month and a year." Description from Australia National University site. The example activity provided has students use SunPath in the yearly mode to investigate seasonal changes in sunrise, sunset, length of day and sun altitude at their own latitude.

Learning Goals

  • Content: Sunrise, sunset, length of day, and sun altitude for the 15th of each month.
  • Students graph:
    • length of day vs. month
    • Sun altitude vs. month
  • Students Graphically estimate their shadow length from their height and the sun's altitude.
  • Students can optionally use trig to check their graphical shadow length results.

Context for Use

This activity can be used as a homework assignment, lab activity, or for interactive lectures in an introductory Geoscience course with discussions related to seasons and the sun.

Description and Teaching Materials

A sample Sun Path activity that will take students about 2 hours to complete is provided here: Sun Path Activity. Other activities can be easily created by the instructor.

Teaching Notes and Tips

This activity requires a working knowledge of a graphing program like Excel or some other software.
  • Introduction to Excel Creating a Chart (more info) from Lamont-Doherty Earth Observatory
  • Typing "Create Chart" in Excel help will guide you through (use XY scatter for x-y graphs)
  • Graphical Analysis is a low cost but high quality graphing program available through Vernier Software (more info)

The Sun Path JAVA applet was tested and worked on both a Windows 98 PC operating system and Mac OS X. The JAVA applet may take some time to load and may not be practical to use over a modem line.

Assessment

Successful completion of this interactive activity is a good measure of student performance.

References and Resources

  • SunClock is a related activity that makes use of tables from the US Naval Observatory
  • Sun or Moon Rise/Set Table (more info) from the US Naval Observatory.
    • FORM A calculates the sun rise and sun set times for anyplace in the US for all days of the year
    • FORM B of the calculates sun rise and sun set times for anyplace in the world