Earth-Sun Relationships / Solar Noon Angles Introduction: The purpose of this lab is to explain the geographic and seasonal variations in the receipt of insolation (incoming solar radiation) that is caused by Earth-Sun geometry. This exercise will allow you to examine how both latitude and season affect sun angle. Earth-Sun Relationships: The distance between Earth and the Sun averages about 150 million kilometers (about 93 million miles). Because of that great distance, and Earth's relatively small size, it is reasonable to assume that the Sun's rays to Earth in straight paths. Earth's axis of rotation is tilted by an angle of 23. 5 from the perpendicular, to the plane of the ecliptic - the imaginary flat plane on which Earth revolves around the Sun. The seasons occur because this tilt is oriented in the same direction throughout the year, with the North Pole always pointing toward the North Star (Polaris). Thus, the Northern Hemisphere is tilted toward the Sun during its summer months, and tilted away from the Sun during its winter months. The image below shows how the Sun's rays strike Earth on both Solstices. For Lab 2, we'll focus on the Solstices. The June Solstice occurs roughly on June 20-21, and on that day, the direct rays of the Sun at local Noon strike 23. 5 North Latitude (also known as the Tropic of Cancer). That is the Northern Hemisphere's first day of Summer; the Southern Hemisphere's first day of winter. Conversely, the December Solstice occurs roughly occurs on December 21-22, and on that day, the direct rays of the Sun at local Noon strike 23. 5 South Latitude (also known as the Tropic of Capricorn). That is the Northern Hemisphere's first day of winter, and the Southern Hemisphere's first day of summer..

1. Earth-Sun Relationships / Solar Noon Angles Introduction: The purpose of this lab is to explain
the geographic and seasonal variations in the receipt of insolation (incoming solar radiation) that
is caused by Earth-Sun geometry. This exercise will allow you to examine how both latitude and
season affect sun angle. Earth-Sun Relationships: The distance between Earth and the Sun
averages about 150 million kilometers (about 93 million miles). Because of that great distance,
and Earth's relatively small size, it is reasonable to assume that the Sun's rays to Earth in straight
paths. Earth's axis of rotation is tilted by an angle of 23. 5 from the perpendicular, to the plane of
the ecliptic - the imaginary flat plane on which Earth revolves around the Sun. The seasons occur
because this tilt is oriented in the same direction throughout the year, with the North Pole always
pointing toward the North Star (Polaris). Thus, the Northern Hemisphere is tilted toward the Sun
during its summer months, and tilted away from the Sun during its winter months. The image
below shows how the Sun's rays strike Earth on both Solstices. For Lab 2, we'll focus on the
Solstices. The June Solstice occurs roughly on June 20-21, and on that day, the direct rays of the
Sun at local Noon strike 23. 5 North Latitude (also known as the Tropic of Cancer). That is the
Northern Hemisphere's first day of Summer; the Southern Hemisphere's first day of winter.
Conversely, the December Solstice occurs roughly occurs on December 21-22, and on that day,
the direct rays of the Sun at local Noon strike 23. 5 South Latitude (also known as the Tropic of
Capricorn). That is the Northern Hemisphere's first day of winter, and the Southern Hemisphere's
first day of summer.