comstock] THE BEGINNING OF STAR STUDY 385 



2 . Is the Dipper moving up or down ? 



3. Do the pointers keep pointing toward the Pole Star? 



4. Does the Dipper move around the Pole Star at night? If 

 . so, does it move in the same direction as the hands of the clock 



or in an opposite direction? 



Bv answering these questions from observation, the pupils 

 may be taught the following facts: The Big Dipper points 

 with its "pointers" toward the Pole Star and to us seems to 

 revolve around it each twenty-four hours, but this appearance is 

 caused by the fact that we ourselves on the earth are revolving 

 from west to east. It is a little more difficult to explain that 



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because of the movement of the earth in its orbit the Big Dipper 

 and all the other stars arrive at a certain point in our sky four 

 minutes earlier each day or about two hours earlier each month. 

 The explanation may seem difficult to the pupils but the facts they 

 should observe for themselves. 



The next lesson should be on Cassiopeia's Chair and the same 

 plan should be followed. Place Diagram Xo. II on the board, 

 showing that the stars are placed to form an irregular W. Explain 

 that it lies on the opposite side of the Pole Star from the Dipper, 

 but at about the same distance from it. After two or three clear 

 nights the following should be given : 



1. Make a diagram (Xo. II) of the Chair, the Pole Star and the 

 Dipper, showing how they are placed in the sky. 



