1. The Moon & Tides (77)

2. Tides Moon and sun contribute to the ocean’s tides. Gravity pulls the ocean water slightly & causes it to bulge out toward the moon. –Opposite side of bulge also slightly bulges (due to earth’s rotation). –This is where high tide occurs.

3. Types of Tides High high (spring) tide: new and full moons, the moon and sun pull in similar directions (higher than normal tides). High tide: side facing the moon (or directly opposite). Low tide: side facing the sun (or directly opposite). Low low (neap) tide: 1 st and 3 rd quarter moons, sun and moon pull in opposite directions (lower than normal tides).

6. Result of Tides Water moving because of tides slows the earth’s rotation - 0.0015s/100years (days are getting longer). –Estimated that 900 million years ago the earth had a 18 hour day.

7. Future of the Earth and Moon Earth also pulls on the moon. –Why the moon keeps the same side facing the earth. Over time the moon’s orbit is growing & moves away ~4 cm/yr. –Measured by lasers.

8. Moon & Tides Diagram (76) Draw 4 pictures of the earth, moon and sun showing when we have the 2 spring tides and the 2 neap tides every month. Indicate the moon phase in each of the 4 pictures. Answer the following questions in complete sentences: 1.Explain why the earth has tides. 2.Explain what the tides are doing to the Earth’s rotation.