Tides

Tides are daily changes in the elevation

of the ocean surface

Caused by the gravitational attraction upon

Earth by the moon and the sun

2 forces that produce tides

• Gravity

• Inertia

Tides

Tides

Tidal range

Difference in height between 2 high tides or 2 low

tides

Spring tides

Tides that have the greatest tidal range

Occur during the full moon and the new moon

Neap tides

Smallest rise and fall in tidal level (small tidal

range)

Neap tides occur during quarter moons

Tides

http://upload.wikimedia.org/wikipedia/commons/c/cf/Chiswick_Eyot_channel_at_low_tide_vs_high_tide.jpg

LOW TIDE HIGH TIDE

Tidal Patterns

3 main tidal patterns exist worldwide

1) Semidiurnal- 2 high tides and 2 low tides

each day (Atlantic Coast of the U.S.)

Tidal Patterns

2. Diurnal- 1 high tide and 1 low tide each

day (northern shore of the Gulf of

Mexico)

Tidal Patterns

3) Mixed tides- inequality in high water

heights and low water heights (Pacific

Coast of U.S. and in other parts of the

world)