Tides are created by the gravitational pull of the sun and moon. This same force also distorts the solid part of the Earth, for while the pull of the moon is creating a high tide on the side of the Earth that is closest to it, it is also pulling the solid part of the Earth on the opposite side away from the water, creating bulges on both sides of the planet. Test your knowledge of tides here.

A. High tides occur approximately:

1. Every 6.5 hours
2. Every 8.25 hours
3. Every 12.5 hours
4. Every 24.25 hours

B. The length of time that a tidal high (wave) takes to move from the mouth to the end of the basin determines the tidal pattern of an estuary.The Bay is just the right length so that as a tidal high reaches the upper limit of the Bay, another tidal high is beginning at its mouth, with a low tide midway. This tidal pattern is called:

1. Semidiurnal tidal pattern
2. Daily mixed tidal pattern
3. Mid-wave tidal pattern
4. Dual tidal pattern

C. An outgoing tide is called:

1. Ebb tide
2. Flow tide
3. Neap tide
4. Spring tide

D. Tides are highest during a:

1. New moon
2. Full moon
3. Blue moon
4. 1 & 2

E. The highest tides occur when the sun and the moon are in a straight line. These tides are called:

1. Ebb tides
2. Flow tides
3. Neap tides
4. Spring tides

F. Tides with the smallest difference between high and low tides occur when the sun and moon are at right angles to the Earth. These tides are called:

1. Ebb tides
2. Flow tides
3. Neap tides
4. Spring tides

G. Halfway between mean high and low tides, this term is used to measure both land elevation and sea depths. What is it?

1. Tidal mean
2. Sea level
3. Mean level
4. Earth rise

H. Tides are highest at the Chesapeake’s capes, intermediate through the mainstem and lowest in the upper sections of tidal streams. What is the vertical range of tides in the main part of the Bay.

1. 1 foot
2. 2 feet
3. 3 feet
4. 4 feet

I. The Bay’s tides aren’t even close to those found at the Bay of Fundy in New Brunswick, Canada, where the world’s highest tides occur. At the Bay of Fundy, tides average:

1. 20 feet
2. 35 feet
3. 45 feet
4. 60 feet

J. Smaller bodies of water, such as lakes and ponds, have no tides. Why?

1. There is not enough water to be attracted by gravitational pull
2. There is no outlet for water to rush in and out.
3. The whole body of water and land beneath it are raised at the same time.
4. Other factors, such as springs, offset the tides.

K. The introduction mentioned that the solid part of the Earth also faces gravitational pull, creating a bulge. This distortion ranges:

1. About 1.75–4.25 inches
2. About 4.5–14 inches
3. About 10.3–21.75 inches
4. About 15.5–30 inches


A-3, B-1, C-1, D-4, E-4, F-3, G-2, H-2, I-3, J-3, K-2