Field, laboratory, and library manual in physical geography . EMENTS OF THE SUN 61 EXERCISE VI THE APPARENT MOVEMENTS OF THE SUN Part I Use the circle drawn in Exercise V. Stand so that the centerof the post is between you and the point of sunrise. Make amark on the circumference of the circle, such that it will be inline with the point of sunrise and the post. Is the point of sun-rise due east? If not, how many de-grees north or south of due east is it?(Should you find the point of sunrise5 degrees south of due east, its directionwould be read east,5 degrees south.)Make a similar ob-servation
Field, laboratory, and library manual in physical geography . EMENTS OF THE SUN 61 EXERCISE VI THE APPARENT MOVEMENTS OF THE SUN Part I Use the circle drawn in Exercise V. Stand so that the centerof the post is between you and the point of sunrise. Make amark on the circumference of the circle, such that it will be inline with the point of sunrise and the post. Is the point of sun-rise due east? If not, how many de-grees north or south of due east is it?(Should you find the point of sunrise5 degrees south of due east, its directionwould be read east,5 degrees south.)Make a similar ob-servation for the sun is duesouth it is said to beon our meridian, andwe call the hour the use of theclinometer (Fig. 1)determine the angleof elevation of thesun when it is onour meridian. (Theangle of elevation isthe angle that a rayof light from the sunmakes with the planeof the horizon.) Setyour watch by thesun at noon and from that determine the exact times of sunriseand sunset. From this determine the length of the day fromsunrise to Fig. 1. The Clinometer When the clinometer is held so that the line AB ishorizontal, the vertical line DO coincides with theline CO. When it is used to determine a verticalangle, All is pointed at the object of observation.])() then departs from CO as much as AB doesfrom the horizontal, hence angle COD is the angleof elevation In determining the angle of elevation of the sun, holdthe clinometer so that the shadow of the pin at Aor at B falls on the line AB. Angle COD is thenthe desired angle 62 PHYSICAL GEOGRAPHY MANUAL Make observations similar to the preceding every two weeksand tabulate your results, giving, in different columns, (a) date,(b) direction of sunrise, (c) direction of sunset, (d) time of sun-rise, (e) time of sunset, (/) length of day, (g) elevation of thesun at noon. Part II When is the day longest? When shortest? When are daysand nights of equal length? How many times each year arethe days and nights of eq
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