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Ocean Topology

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Subido el 28 de mayo de 2007 por EducaMadrid

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Eighth segment of the Ocean Odyssey describes Ocean Topography and where oil seepage comes from.

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I'm here at VIMS with Ms. Masellus. 00:00:00
She's showing me the vessels they use to map and take core samples. 00:00:03
We learned that there are mountains and valleys on the ocean floor 00:00:06
and that there's natural oil seepage. 00:00:09
We need to know more about the topography of the ocean. 00:00:11
Can you tell me exactly what the floor looks like? 00:00:14
It's magnificent. 00:00:16
Under the ocean, you can find the tallest mountains, 00:00:17
the deepest valleys, and the flattest plains on Earth. 00:00:19
Sounds fascinating, but I don't see any mountains or valleys when I swim. 00:00:22
That's because where you swim is actually the continental shelf. 00:00:26
This area is located along the edge of the continent 00:00:29
and can extend 10 to 200 kilometers offshore. 00:00:31
So are mountains the next area? 00:00:34
No. Next comes the continental slope. 00:00:36
It starts at the edge of the shelf and dips steeply until you reach the abyssal plain, 00:00:38
which is one of the flattest areas on Earth. 00:00:42
And the next area is where the tallest mountains are, right? 00:00:44
Right. In the middle of the ocean, there are mountain ridges called mid-ocean ridges. 00:00:47
This is where the seafloor is spreading apart, making new seafloor and building mountains. 00:00:51
I learned about the seafloor spreading apart in the case of the shaky quake 00:00:55
when we learned about plate tectonics. 00:00:59
Very good. You'll also find volcanoes over those ridges and over hot spots in the Earth's crust. 00:01:01
If a volcano grows tall enough to rise above sea level, they form islands. 00:01:06
Just like the Hawaiian Islands. Didn't they form over a hot spot? 00:01:10
That's right. And if a volcano doesn't break the surface of the water, then it's called a seamount. 00:01:14
There are also deep ocean trenches. 00:01:18
I always thought of the ocean as sandy. 00:01:19
Under the ocean is a whole world just waiting to be discovered. 00:01:21
And that's where the core samples come in. 00:01:24
Why do you take core samples of the ocean floor? 00:01:25
Seismic reflection images show buried ancient river channels located near here during the last ice age. 00:01:28
Coring helps us to verify that they exist. 00:01:33
It seems like we have another mystery, and we need your help. 00:01:35
Sure thing. What can I do? 00:01:38
Right now, we're trying to find out where the oil globs on our beach came from. 00:01:39
Mr. Wells said that oil sometimes seeps out naturally from the ocean, 00:01:43
so we need to learn more about oil seeps. 00:01:47
Oil and gas can seep directly onto the surface of the earth or into the oceans. 00:01:49
Are seeps very common? 00:01:53
Yes, they're quite common. 00:01:55
Did you know in California, every oil and gas field discovered between 1860 and the early 1900s 00:01:56
was actually found by people seeing it seep up from the earth? 00:02:02
So how does oil and gas seep out? 00:02:05
Seeps can come from a single point or from as many as 30,000 individual little holes. 00:02:07
Divers describe high seepage areas as looking like a whole bunch of gopher holes. 00:02:11
How much oil and gas seeps out? 00:02:15
It varies from place to place and can range from nearly impossible to detect 00:02:17
to thick oil films with globular deposits called tar balls. 00:02:21
That sounds like what's on our beach. 00:02:24
We learned that most of the oil seepage occurs along the Gulf of Mexico, 00:02:26
so we thought that a current could be carrying the oil globs to our beach. 00:02:30
But we learned that there aren't any currents that carry things to Virginia from the Gulf of Mexico. 00:02:33
What about the Gulf Stream? 00:02:38
We know that the Gulf Stream flows northward from the central part of the Atlantic Ocean 00:02:39
and turns back towards Europe up around Canada. 00:02:43
So I don't think that's the answer. 00:02:46
You might want to learn more about the Gulf Stream. 00:02:48
You're right. Maybe it is the Gulf Stream. 00:02:50
Thanks, Ms. Vassalos. 00:02:52
You're welcome. It's my pleasure to help out the treehouse detectives. 00:02:54
Let me show you something else. 00:02:56
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Idioma/s:
en
Niveles educativos:
▼ Mostrar / ocultar niveles
      • Nivel Intermedio
Autor/es:
NASA LaRC Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
585
Fecha:
28 de mayo de 2007 - 15:34
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
03′ 01″
Relación de aspecto:
4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
Resolución:
480x360 píxeles
Tamaño:
18.27 MBytes

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