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1.7 Seasons

Pre-Lecture Reading 1.7

Video Lecture

Supplementary Notes

Cause of Earth's Seasons

Notable Times

Summer Solstice

Autumnal Equinox

Winter Solstice

Vernal Equinox

Notable Latitudes

Arctic Circle (+67.6°) and above

Tropic of Cancer (+23.4°)

Equator (0°)

Tropic of Capricorn (–23.4°)

Antarctic circle (–67.6°) and below

Exercises

  • Experiment with UNL's Seasons Simulator.
  • Experiment with UNL's Union Seasons Demonstrator.
  • Experiment with UNL's Paths of the Sun.
  • Experiment with UNL's Sun Motions Overview.
  • Experiment with UNL's Sun Motions Demonstrator. (Hide the ecliptic.)
  • Experiment with UNL's Sun's Rays Simulator.
  • Experiment with UNL's Daylight Hours Explorer.
  • Experiment with UNL's Daylight Simulator.
  • Using this worksheet, keep track of roughly how high the sun is in the sky around midday as the semester progresses. Do not look directly at the sun! Rather, block it with your hand and estimate how many degrees your outstretched arm is above the horizon. 0° is on the horizon. 90° degrees is overhead. Also, keep track of roughly how long the day is as the semester progresses. If you are not up for sunrise, keep track of how many hours are between noon and sunset and double it (if daylight saving time, subtract an hour before doubling). Since it will probably take a month or two to notice trends, you need only do this every week or two. Do not simply look up the numbers on the internet! The point of this exercise is to see these trends with your own eyes.

Lab Link

Material presented in this unit is related to material presented in Lab 2 of Astronomy 101 Laboratory: Our Place in Space. In Lab 2: Earth and the Seasons, we:
  • Determine how length of day changes with latitude and season.
  • Determine how the height of the sun in the sky at midday changes with latitude and season.
  • Measure Earth's diameter.

Video Lab Summary

Assignment 1

Do Questions 4–6.