1. Tides

4. The Sun’s mass is 27 million times that of the moon, but it is also 390 times farther from the earth. So although the sun affects our tides, the moon exerts the greater gravitational attraction because of its proximity to our planet .

7. This is high tide at Douglas (in Juneau, Alaska). Photo from Daniel Cornwall at Alaskan Librarian .

8. This is Douglas at low tide. Photo from Daniel Cornwall at Alaskan Librarian .

12. Spring and Neap Tides - At what moon phases do these occur?

13. Look for the phases!