Geometry and the Cause of the Seasons: The Changing Hours of Daylight and Elevation Angle of the Sun at Noon

• Margaret Stautberg Greenwood ^[1]
  1. [1] Richland
• Localización: The Physics Teacher, ISSN 0031-921X, Vol. 60, Nº. 8, 2022, págs. 694-698
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • From my home on the west bank of the Columbia River in Richland, Washington (46.3°N latitude), I have an unobstructed view of the sunrise along the east bank during an entire year. As a retirement project after a career of teaching and research in physics, I decided to take photographs of the sunrise for a year and, and at the same time, carry out calculations to determine 1) the hours of daylight on a given day and 2) the elevation angle of the Sun at noon. My goal is to use geometrical diagrams along with a simplified model so that results are very easy to understand. In this model, the spherical Earth revolves around the Sun in a circular orbit, and the parallel sunbeam striking Earth is directed along a line connecting their centers. However, Earth’s axis of rotation maintains the same direction throughout its motion around the Sun, which causes the seasons and the variations that we observe.