THE HEIGHT OF THE SUN AT NOON 15 



9. The Height of the Sun at Noon. 



When is the sun highest in the sky? If the sun is 

 in line with the surface of the earth at sunrise, and grad- 

 ually becomes higher then gradually becomes lower un- 

 til at sunset it is again in line with the surface of the 

 earth, the highest point must have been reached half- 

 way between sunrise and sunset. What time is this? 

 What can you say about the length of shadows at sunrise 

 and at noon? At sunset and at noon? When is the 

 shortest shadow? Is the length of a shadow at noon al- 

 ways the same? If you do not know, how are you going 

 to find out? The varying length of a shadow shows the 

 height of the sun. 



Experiment 9. The Height of the Sun at Noon by 

 Means of a Shadow. 



a. Measure the length of the shadow of a window- 

 sill where the sunlight falls upon the floor at noon. 



b. One week later measure it again. Is it the 

 same? Continue to measure the shadow once a week, 

 keeping a record of the lengths similar to the record 

 used in Experiment 6. Later you will have some ques- 

 tions about this experiment to answer. See Section 69. 



We can measure the height of trees and buildings 

 and mountains in feet and inches but we cannot measure 

 the height of the sun in this manner. We always meas- 

 ure the height of the sun and stars by the number of de- 

 grees which we have to look upward from the surface of 

 the ocean or a lake. We call looking along the surface of 



