LABORATORY MANUAL 11 



3. State the direction of the noon shadow from the pin. 



4. State the direction of the afternoon shadows from the 

 pin. 



5. In what direction would you look for the sun at noon? 



6. Before noon? 



7. What differences in the length of shadows do you 

 observe? 



8. Were any two shadows nearly equal in length? Which 

 ones? 



9. Give directions for making a sundial which "tells 

 time" by the direction of sun shadows. 



EXERCISE III (Textbook 26) 

 ORBITS OF SOME OF THE PLANETS 



APPARATUS: Hard pencil, ruler, compasses. 



DIRECTIONS FOR WORK: In the middle of the space 

 below [on p. 2 of notebook sheet], place the letter S. Con- 

 struct three circles (with the same center, S) having a 

 radius of J in., f in., and 2| in., respectively. On the left, 

 place V (Venus) on the smallest circle, E (Earth) on the 

 second, J (Jupiter) on the largest, all in the same line from 

 S. Let the circles represent the orbits or paths of one 

 revolution of the earth and these two other planets about 

 the sun. (NOTE. The orbits of the planets are ellipses, not 

 circles, but it is not possible to represent their form correctly 

 in small drawings.) 



RESULTS 



1. What fraction of its orbit represents the earth's journey 

 for six months? 



2. How many degrees does the earth pass over in that 

 time? 



3. How long does it take the earth to pass over 90? 



4. Hpw long does it take Venus? 



