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OCEAN MOVEMENT - Coggle Diagram
OCEAN MOVEMENT
INTRODUCTION
Ocean movement is created by the governing principles of physics and chemistry. Friction, drag, and density all come into play when describing the nature of a wave, the movement of a current, or the ebb of a tide.
CURRENTS
A large movement of water in one general direction is a current.
Surface currents
Sun and Wind
Wind is a major force in propelling water across the globe in surface currents. When air moves across the ocean’s surface, it pulls the top layers of water with it through friction
These wind patterns are created by radiation from the Sun beating down on Earth and generating heat.
Gravity and Earth's Rotation
Following the pull of gravity, ocean water moves from the built-up areas of high pressure down to the valleys of low pressure.
The Earth is constantly rotating, meaning every object on its surface is moving at the speed at which the Earth is spinning on its axis. It also influences the movement of ocean currents. Scientists refer to this bending as the Coriolis Effect
https://www.youtube.com/watch?v=D2rUtp7g3ms
Swirling Gyres
Earth’s rotation is also responsible for the circular motion of ocean currents. There are 5 major gyres on Earth: the Northern Atlantic, the Southern Atlantic, the Northern Pacific, the Southern Pacific, and the Indian Ocean.
Similar to surface waters, Northern gyres spin clockwise (to the right) while gyres in the south spin counterclockwise (to the left).
https://www.youtube.com/watch?v=p4pWafuvdrY
Ekman Transport
When water moves across Earth’s surface it bends due to the Coriolis Effect. The top most layer of water will bend away from the direction of the wind at about 45 degrees, which is known as the Ekman transport.
Deep currents
The ocean is connected by a massive circulatory current deep underwater. This planetary current pattern is called the global conveyor belt
When cold, salty water circulates the globe and gradually becomes warmer, it begins to rise.
https://www.youtube.com/watch?v=H9glfUeJ6mY
Rip currents
Rip currents are strong, narrow, seaward flows of water that extend from close to the shoreline to outside of the surf zone
It can move at speeds as fast as eight feet per second. At these speeds, a rip current can easily overpower a swimmer trying to return to shore.
https://www.youtube.com/watch?v=VOyrHaF2iRc
WAVES
Is a ridge or swell on the surface of a body of water
A wave forms in a series of crests and troughs. The crests are the peak heights of the wave and the troughs are the lowest valleys
Waves on the ocean surface are usually formed by wind. The faster the wind, the longer it blows, or the farther it can blow uninterrupted, the bigger the waves.
The largest waves occur where there are big expanses of open water that wind can affect.
A classic tsunami wave occurs when the tectonic plates beneath the ocean slip during an earthquake.
https://www.youtube.com/watch?v=tibbbT9Li5E
TIDES
Tides exist thanks to the gravitational pull of the Moon and the Sun, but vary depending on where the Moon and Sun are in relation to the ocean as Earth rotates on its axis.
https://www.youtube.com/watch?v=HdI_PyMFNro
When the Sun and Moon are in line with one another they reinforce each other’s gravitational pulls and create larger than normal tides called spring tides.
Smaller than usual tidal ranges, called neap tides, occur when the gravitational force of the Sun is at a right angle to the pull from the Moon. The two forces of the Sun and Moon cancel each other out and create a neap tide.
Tides are actually waves, the biggest waves on the planet, and they cause the sea to rise and fall along the shore around the world.
CONCLUSION
Currents, tides and waves are essential for marine life, since many organisms depend on them for their migrations, feeding, reproduction, etc. Also, these water movements create great economic income around the world.
