46 NATURE STUDY REVIEW [10:2— Feb., 1914 



questions should be asked concerning what the pupils have seen 

 of the Dipper. The drawing should be erased from the board 

 and each pupil should make a drawing for himself of the Dipper 

 and the Pole Star as remembered. And this drawing should not 

 be accepted until the proper nimiber of stars are placed for the 

 bowl and the handle and the proper relation of the pointers to 

 the Pole Star are indicated. The following questions should be 

 asked to stimulate further observations : 



1. Look at the Big Dipper at 6:30 in the evening and again 

 at 8 or 8:30. Does it keep the same position in relation to the 

 Pole Star? 



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 ? 



By 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 re- 

 volve 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 difficiilt to explain that be- 

 cause 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 be 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 No. 2 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, 



,^ 



Cassiopeia's Chair Diagram II Pole Star 



