Tides
Take-Away Points
1. Tides in the ocean are caused by both the Sun
and Moon
2. Tides occur because the Sun and Moon pull
stronger on one side of the earth than the other
3. There are two tidal bulges on opposite sides of
the Earth
4. Solar and Lunar tidal effects can reinforce or
weaken each other
5. Actual tide motions in the oceans are very
complex
6. Tides are gradually slowing the earth’s rotation
There are
Two Tidal
Bulges
3. There are two tidal bulges on opposite sides of the Earth
Both Moon and Sun Cause Tides
4. Solar and Lunar tidal effects can reinforce or weaken each other
Tides and the Boston Tea Party,
December 16, 1773
•
•
•
•
Near Earth's perihelion: strong solar tides
Near lunar perigee: strong lunar tides
Full moon on December 13: spring tide
Overall effect: unusually large tidal range
4. Solar and Lunar tidal effects can reinforce or weaken each other
The Boston Tea Party, December 16,
1773
4. Solar and Lunar tidal effects can reinforce or weaken each other
Tides and the Battle of Tarawa,
November 20, 1943
•
•
•
•
Near Earth's perihelion: strong solar tides
Near lunar apogee: weak lunar tides
Near last-quarter moon: neap tide
Overall effect: unusually small tidal range
4. Solar and Lunar tidal effects can reinforce or weaken each other
Location of Tarawa
4. Solar and Lunar tidal effects can reinforce or weaken each other
The Attack on Tarawa
4. Solar and Lunar tidal effects can reinforce or weaken each other
Tarawa: What the Planners Wanted
4. Solar and Lunar tidal effects can reinforce or weaken each other
What Actually Happened
1027 Marines killed, 2292 wounded
4. Solar and Lunar tidal effects can reinforce or weaken each other
Tides and the
Real Oceans
5. Actual tide motions in the oceans are very complex
How Tides Move in the Oceans
5. Actual tide motions in the oceans are very complex
Tides on the Real Earth
5. Actual tide motions in the oceans are very complex
Tides
Affect
Earth's
Rotation
6. Tides are gradually slowing the earth’s rotation
Take-Away Points
1. Tides in the ocean are caused by both the Sun
and Moon
2. Tides occur because the Sun and Moon pull
stronger on one side of the earth than the other
3. There are two tidal bulges on opposite sides of
the Earth
4. Solar and Lunar tidal effects can reinforce or
weaken each other
5. Actual tide motions in the oceans are very
complex
6. Tides are gradually slowing the earth’s rotation