EXERCISE 19 



WHAT EFFECT DOES THE ROTATION OF A GLOBE HAVE UPON THE DIRECTION OF 



MOTION OF OBJECTS ON ITS SURFACE? 



Materials. A globe (preferably a slated globe) mounted so that it may be rotated readily ; a 

 pitcher or dish of water. 



Directions. Place the globe in a position with its axis vertical. With the globe stationary pour 

 a little water on its upper end, which may be marked " north pole." Note that the water flows to 

 the other pole. Its path is like a meridian. 



After drying the globe^ rotate it in the direction in which the earth rotates west to east. 

 Pour a little water on the globe while rotating. When it has come to rest note the path which 

 the water made. Is its path a meridian of the globe ? Does it curve to its right or to its left on 

 the upper half (northern hemisphere)? Does it curve to its right or its left on the lower half 

 (southern hemisphere) ? ' 



If this holds good for the earth as well as for a small globe, what are your conclusions about 

 the effect of the earth's rotation upon the direction of the winds ? What have you seen upon the 

 weather map which agrees or disagrees with this? 



Additional problem. Can you determine what would be the prevailing direction of the wind if the earth 

 did not rotate ? 



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