420 likes | 727 Views
Tides. The rising of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the oceans. Bay of Fundy at high tide. Bay of Fundy at low tide. Tidal Cycle. A tide is a repeated cycle of sea level changes in the following stages: 1st step
E N D
Tides The rising of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the oceans. Bay of Fundy at high tide Bay of Fundy at low tide
Tidal Cycle A tide is a repeated cycle of sea level changes in the following stages: 1st step Over several hours the water rises or advances up a beach in the flood tide.
Tidal Cycle A tide is a repeated cycle of sea level changes in the following stages: 2nd step Water reaches its highest level, stops at high water. Tidal currents cease. Called slack water or slack tide. Tide reverses direction and is said to be turning.
Tidal Cycle A tide is a repeated cycle of sea level changes in the following stages: 3rd Step The sea level lowers or falls over several hours during the ebb tide.
Tidal Cycle A tide is a repeated cycle of sea level changes in the following stages: 4th Step The level stops falling at low water. This point is also described as slack tide or turning.
Tidal Cycle A tide is a repeated cycle of sea level changes
Tides As the Earth rotates, the moon’s gravity pulls water toward the point on the Earth’s surface closest to the moon. http://www.onr.navy.mil/Focus/ocean/motion/tides1.htm
Spring Tides During new moon and full moon, the sun, moon, and Earth are almost in alignment. The combined gravity causes higher than normal high tides and lower than normal low tides
Neap Tides 1st and 3rd quarter moon is at right angles to sun and Earth. The sun’s pull is at right angle to the Earth, causing lowest height difference between tides
1st Quarter Moon 3rd Quarter Moon
Use the Force, Luke.. Tidal force - secondary effect of the force of gravity, responsible for the tides. It occurs because the gravitational force exerted on one body by a second body is not constant across its diameter. The side nearest to the second body experiences a greater force, while the opposite side experiences a lesser force. http://www.gly.uga.edu/railsback/Tides/TideHammer01.html http://www.pbs.org/wgbh/nova/venice/tides.html
Once a day Diurnal Tides - In parts of the northern Gulf of Mexico and Southeast Asia, tides have one high and one low water per tidal day
Twice a day Semi-diurnal tides - two high and two low waters per tidal day. They are common on the Atlantic coasts of the United States and Europe.
Can’t Decide! Mixed tides - where successive high-water and low-water levels change a great deal. In these tides, we have a higher high water and lower high water as well as higher low water and lower low water. The tides around west coast of Canada and the United States are of this type.
When do we dock? Channel = 15 meters Dockside depth = 15 meters Draft of ship = 12.5 meters
Wave characteristics • Wavelength (L): distance between crests • Wave Height (H) : vertical distance between crest and trough • Wave Period (T): time for successive waves to pass a fixed point
Kiawah Island
Morris Island Lighthouse Coast Guard Station