THE USE OF SONAR, AND THE THEORY OF
SEAFLOOR SPREADING.
By: Rishon Pryce, Kaylee French
Period – 6
09/21/15
SONAR.
The definition of sonar is:
• Sonar (an acronym for sound navigation is a
way to use sound to navigate,
communicate or detect objects on or under
the surface of the water, such as vessels.
• There are two types of sonar, one
being Active Sonar which emits
pulses, or signal of sound that goes
down and bounces off objects and
returns such as an echo.
• The depth can be determined be
the time is takes for the signal or
pulse to return to the ship.
• Sonar became an important tool to oceanography when people
found a way to use it to see the ocean floor. When the signal came
back it painted a picture in a way that showed the ocean floor and
what it looked like such as the different depths.
• The use of sonar showed how much deeper the ocean was
compared to what people thought, this really opened peoples eyes
to the new things that lie within the oceans depths.
Seafloor spreading.
Seafloor spreading- is a process that occurs at mid-ocean ridges, where
new oceanic crust is formed through volcanic activity and then
gradually moves away from the ridge.
Seafloor spreading helps explain continental drift in the theory of plate
tectonics.
• Seafloor spreading and other tectonic activity processes
are the result of mantle convection. The mantle melts and is
pushed up through the ocean floor. The crack where the
magma flows out is where the plates are being pulled
apart.
• This makes what is known as the mid ocean range. The mid
ocean range is a range on mountains created be the hot
magma that flows from within earths crust.
• The theory of seafloor spreading also helps to explain plate
tectonics and how everyone lives on large moving mass of
land.
• Sea floor spreading occurs in the Atlantic ocean between
north America, and Africa. On the opposite side of the
earth, the sea floor is doing the opposite of spreading and is
being pulled back into the earth.
• This process is called subduction, scientist suggest that the
continents will join back together in the future.
• The earth will always stays the same size, just because the
ocean floor is growing does not mean that the earth is
growing in size. Many people can not understand this and it
is also the reason that the theory of seafloor spreading is still
a theory. There is evidence of this though, in the pacific
ocean, the earths crust is being pulled back in to earth.
•Credits
• http://education.nationalgeographic.com/encyclopedia/s
eafloor-spreading/
• http://www.bing.com/images/search?q=subduction&view=
detailv2&&id=7C4738C624396A4AD5B31B98992C4059F4C3C
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co0&ajaxhist=0