tides and waves Flashcards
What are tides?
short-term changes in water level, caused by a combination
of the gravitational pull of the sun & moon and the rotation of the Earth
What three things affect tides?
Gravitational pull (rotational pull), weather, and wind
How does the moon affect tides?
The moon exerts a gravitational pull-on Earth and the oceans. This causes the water directly lined up with the moon to “bulge” or create a
high tide
describe the bulges stated in other question.
Two bulges—one bulge toward the Moon where the Moon’s gravity dominates
and the other bulge away from the Moon where centrifugal force predominates.
How does the sun affect tides?
The sun also exerts a gravitational force on Earth and the oceans, but it’s not as
strong as the moon b/c it’s farther away. Therefore, the gravitational pull of the
sun either adds to or works against the moon’s gravitational pull. The effect of
the gravitational pull of the Sun on Earth is only about half as strong as the
Moon’s.
When does the sun and moons gravitational force work together?
During the
spring tides (New and Full Moon)
do
Relate spring and neap tides to the phases of the moon.
Spring Tides-Occur when sun, moon, and Earth are in line during new or full
moon
How often do they occur?
Neap Tides-Occur when the sun, moon, and Earth are at right angles (during 1st
or 3rd quarter moon)
what are the 3 types of tidal patterns
(diurnal tides, semi-diurnal tides, mixed semi-
diurnal tides).
Describe the 3 types of tidal patterns (diurnal tides, semi-diurnal tides, mixed semi-
diurnal tides).
Diurnal tides- ONE high tide and ONE low tide every day
Semi-Diurnal tides- Two EQUAL high tides and two EQUAL low tides each day
Mixed Semi-diurnal tides-Two UNEQUAL high tides and two UNEQUAL low tides
every lunar day.
Where can each one be found in the United States?
diurnal -Occurs in Gulf of Mexico and coast of Antarctica
semi - Occurs on East Coast of U.S.& African coasts
mixed- Occurs on West Coast of U.S.
What is a Flood tide?
.The effect of the gravitational pull of the Sun on Earth is
only about half as strong as the Moon’s.
Ebb tide?
is when the water is rushing back toward the sea.
What is slack water?
The period of time between flood and ebb tides
How are tides important to marine animals?
Many animals, such as grunion,
coral, and horseshoe crabs, time their reproduction to coincide with certain
tidal patterns
