Answer these multiple choice questions to the best of your abilities using your knowledge from the lessons and activities that we have completed. Select the best answer to each question from what you know now. If you are not sure about an answer, make your best educated guess.

1.     What is "mean sea level"?
a. The water line at the beach.
b. The horizon viewed from the shore.
c. The average height of all of the oceans.
d. The water depth at high tide.
e. The water depth at low tide.

2.     In which of the following diagrams will the point marked by the X be experiencing the highest tides?  (The small circle is the moon.  The large circle is Earth.

a.	b.
c.	d.

a.

b.

c.

d .  Not enough information is given to answer the question

4. How can we measure sea level?
a. with a large ruler
b. with an electronic sensor.
c. using satellite technology.
d. All of the above.
e. None of the above.

5. The following graph represents the last eighteen hours from a tidal measuring station.  Using this graph, when was the last low tide measured?

a.     It is currently low tide
b.      2 hours ago
c.       6 hours ago
d.      12 hours ago

6.  How often does sea level change?
a. Sea level changes with the seasons.
b. The sea level is always changing.
c. When there is a major shift of the Earth's axis, sea level changes.
d. Never, sea level remains constant.

7.  In order to measure water levels, electronic sensors work by periodically bouncing signals off the water level and measuring the time intervals between transmission and reception.  What type of signal is used?
a.       Light
b.      Laser
c.       Sound
d.      Radio

8.  The cyclical rise and fall of sea level is called _________. ?
a. average sea depth
b. wave surge
c. eddies
d. tides

9.  What are the lengths of the two major tidal cycles?
a.       Daily, monthly
b.      Monthly, annually
c.       Daily, annually
d.      Biannually, twice daily

10.  What are some activities or industries affected by tidal changes?
a.       sun bathing, surfing, and fishing
b.      fishing, hunting, and surfing
c.       beachcombing, surfing, and the railroad industry
d.      shipping, surfing, and beachcombing

11.  Why are tides important to beachcombers?
a.       When the tide is high, beachcombers may find many shells on the shore.
b.      When the tide is low, beachcombers may find many shells on the shore.
c.       Tides are not important to beachcombers because shells are always on the beach.
d.       Tides can indication where to find sand dollars.