Color plate #3 Questions
Tides

1.  What forces cause tides?





2.  Define gravitation.




Which has the greater gravitational pull on the earth’s water – the sun or the moon?  Why?




3.Define centrifugal force.




4.  What are the bulges of the water called?  How can you tell if it is high tide or low tide?




5.Describe the position of earth, sun and moon during the spring tides.





6.  What factors can modify the tidal variation on earth?