Part 1. Moon Phases
A. Luminous1. Produces its own light (Sun, stars)
B. Illuminated1. Seen by reflected light (moon, planets)
C. Moon Phases1. Apparent changes in the shape of the
moon (different parts are illuminated by the Sun)
2. Moon Lit Up
Part 1. Moon Phases
D. Waxing1. Moon “growing” in size2. Light on RIGHT side
E. Waning1. Moon “shrinking”2. Light on LEFT side
F. Synodic Month1. Time to complete the moon phase
cycle2. 29.5 days
Part 3. Moon Motions
A. Time for Moon to Revolve = 27.3 days
B. Time for Moon to Rotate = 27.3 days
C. Rotation = Revolution, so same side of moon always faces the Earth
D. Moon Phase Cycle = 29 days (moon must catch up to the Earth)
Part 4. Tides
A. Daily rise and fall of oceans
B. Caused by the pull of gravity of the moon AND the Sun
C. Moon has a greater effect since it is closer to the Earth
Part 4. Tides
D. Spring Tide (nothing to do with season)A. The highest high tide and lowest low tide
occurs
B. Gives the maximum difference between high and low tides
C. Happens during new or full moon
Part 4. Tides
E. Neap TideA. Lowest high tide and highest low tide
B. Gives minimum difference between high and low tides
C. Happens during Quarter moons
Part 4. Tides
F. Time from one HIGH tide to the next HIGH tide is 12 hours and 26 minutes
G. There are about 2 High and 2 Low tides per day
Importance of Waves
• Shaping Coastlines– Erode cliffs– Grind rock into sand
• Ecology– Returns O
2 to water
– Stir up food for filter feeders
Tides• The rhythmic rise and fall
of the ocean’s water
High tide = rising, incoming tide, flowLow tide = receding, outgoing
tide, ebb
Slack tide = vertical movement stops
• Tides are very long, slow waves
– They have a wave period of 12 hours 25 min
– Tidal day is 24 hours 50 min
– NJ has 2 high and 2 low tides daily
1. Gravitational pull of sun & moon on Earth
What Causes Tides?
• Moon closer, therefore > effect
• Like magnet, pulls water away from surface = TIDAL BULGE
2. Centripetal Forces
• Produced by motions of Earth, sun, & moon
• Bulge on opposite side because centr. force > pull of moon
Types of Tides
– 2x’s/month
•Spring Tide - Moon and sun are in direct
line with one another- Results in unusually high
tidal range
-Tidal Range = vertical distance between high & low tides
• Neap Tide– sun and moon are at right
angles
– Pulls cancel each other out – causes a weak pull
– unusually low tidal range
– 2 x’s / month
Distance bet. Moon & Earth
Perigee Tides• Moon closest to earth, very high tides (causes
flooding)
Apogee Tides• Moon farthest away from earth, very low tides
Types of Tides Continued• Diurnal Tides
– 1 high & 1 low / day– Parts of Gulf of Mexico and Asia
• Semi-Diurnal Tides– 2 high & 2 low / day– Atlantic coasts of North America and Europe
• Mixed– 2 high & 2 low / day (height varies)– Pacific coast
Importance of Tides
• Expose & submerge orgs
• Circulate water in bays & estuaries
• Trigger spawning (grunion, horseshoe crab)
• Circulates food, wastes, etc
Currents• What are currents?
- “Rivers” of circulating water
• Causes- Wind
- Rotating Earth
- Density Changes
• Gulf Stream
- Brings warm water from equator north along east coast of N. A.
- N. Atlantic
-Sometimes form eddies – circulating water that pinches off from the current
RIP CURRENT
- Caused by converging longshore currents
- Very dangerous ; Red Flag
- DO NOT fight rip current; swim parallel to shore to get out of channel
Deep Ocean Currents
• Separated from surface currents by boundary called a “Thermohaline” (diff in densities)
Flow beneath surface; cross Flow beneath surface; cross equatorequator
Move North to SouthMove North to South