Study Guide: Coastal erosion, rip currents, longshore currents, tides, moon phases,
ocean water chemistry, deep currents.
Answer all questions using the resources in your notebook. Ask Mr. G ahead of time
if there are questions that you can’t find. Study and practice the material the week
before the quiz.
1. What is coastal erosion? The movement of sand and rocks due to forces
from waves and currents
2. Describe how Seabright Beach is an example of coastal erosion? We
measured the width of the beach and it was smaller after the storm
because sand eroded
3. What are 2 viewpoints presented in the Fire Island article regarding coastal
erosion? the erosion is a natural process so we could be wasting money
trying to stop it OR we need to protect the houses and property in coastal
areas
4. What is longshore drift? How does it affect the shoreline? What causes it?
Longshore drift transports sand along the beach; it erodes beaches in
some places and builds up beaches in others; it is caused by waves
approaching the beach at an angle and creating a longshore current
5. Draw a labeled diagram showing how/why longshore drift happens.
6. What is a rip current?
A river of water that flows away from the beach into the ocean
7. How/why does a rip current form?
A)Waves crash on a sand bar and water builds up on the beach side
B)water breaks through sandbar
C) water rushes out through hole in sandbar
8. What are some visual clues that a rip current is present: cloudy water,
waves break differently, foam, seaweed or debris moving seaward, a
channel of churning choppy water
9. What should you do if caught in a rip current? Stay calm, do not swim in
but swim sideways (parallel to the shore) and then in, wave hands and
call for help
10. What are tides and what causes them? The regular rise and fall of the
ocean. Caused by the gravitational pull of the sun and moon.
11. What is a spring tide and when will it occur? A large difference between
high and low tide- extreme high and low tides. They occur when the earth,
sun and moon are in line (full and new moon).
12. What is a neap tide and when will it occur A small difference between high
and low tide- average tides. They occur when the earth, sun and moon are
at right angles (1st and 3rd quarter).
13. Why are spring tides higher and lower that most tides (use “gravity” in your
answer). Spring tides are more extreme because the gravity of the sun
and moon has a greater combined effect on the Earth making the water
“pile up” more.
14. On the east coast (see Sandy Hook graph), how many low tides do we have
each day (24 hrs)? 2 low
15. How many high tides do we have each day (24 hrs)? 2 high
16. Draw and label a diagram of the Earth, sun and moon during a spring tide
and during a neap tide.
17. How do low tides affect the salinity of the water in the intertidal zone?
During a low tide, salinity can become greater if water evaporates or
much lower salinity if it rains
18. How do the low tides affect temperature in the intertidal zone?
During a low tide, areas in the intertidal zone can become very cold or very hot
depending on the air temperature
19. What adaptations do sea stars have that helps them to survive in the
intertidal zone?
Tough skin to keep from drying out and tube feet to hold on in high wave zone
20. What adaptations do sea anemones have that helps them to survive in the
intertidal zone? Can secrete mucous to hold water in and keep from drying
out
21. Draw and label the moon phases in order from new moon to a new moon.
Use waxing and waning terms in your answer.
22. What is salinity? The amount of dissolved salt and minerals in sea water
23. What is the average salinity of ocean water? 35 parts per thousand
24. Describe the salinity of water near the poles (where there is a lot of ice).
The salinity is greater due to the freezing of fresh water and leaving salt behind
25. What is a deep current?
A current that flows vertically due to differences in water density
26. Describe what happens in the ocean when cold water interacts with warmer
water. Use an example from the class
The cold water sinks because it is more dense
27. Describe what happens in the ocean when higher salinity water interacts
with lower salinity water. Use an example from class.
The high salinity water sinks because it is more dense