1. The Oceans More than 70% of Earth’s surface is covered by water.
- The Oceans, Waves, Tides & Currents
More than 70% of Earth’s surface is covered by water.
The Oceans
Pacific – largest & deepest
Atlantic – ½ the size of the Pacific
Indian – third largest
Southern – surrounds Antarctica – South Pole
Arctic – smallest – mostly frozen – North Pole - shallowest
origins of the oceans  4 min
4 min Five Oceans

2. The Ocean Floor Ocean Basin – the part of the Earth covered by ocean.
Continental Margin
The Ocean Floor
Ocean Basin – the part of the Earth covered by ocean.
Continental Shelf – starts at the shore and slopes gently into the ocean
Continental Slope – begins at the edge of the shelf and continues to the flatter part of the deep ocean floor.
2 min the ocean floor

3.
8 ½ min  deep ocean
Deep-Ocean Basin
The Abyssal Plain
Most of the ocean floor is a huge, dark, flat region know as the abyssal plain.
Covered in mud with the remains of animals
One of the flattest places on Earth.
= 2 ½ miles

4. Ocean Trenches An ocean trench is a large, V-shaped valley.
Deep-Ocean Basin
Ocean Trenches
An ocean trench is a large, V-shaped valley.
Formed by two oceanic plates pushing into one another and the heaviest plate forced under the other plate.
Trenches are the deepest places in the oceans.
trench 4 min

5. Mid-Ocean Ridges Mid-ocean ridges are underwater mountain ranges.
3 min Mid-Atlantic Ridge
Deep-Ocean Basin
Mid-Ocean Ridges
Mid-ocean ridges are underwater mountain ranges.
Longest mountain chain on Earth – 40,000+ miles
Form on the ocean floor where two plates pull apart and magma comes up to form the mountains.

6. Deep-Ocean Basin
Mid-Ocean Ridges
Where the two tectonic plates pull apart, a rift valley is formed between the ridges of mountains.
In the Atlantic Ocean, the rift valley is miles wide.
New crust is formed in the rift valley.
Iceland was formed from a mountain within a mid-ocean ridge.

7. Deep-Ocean Basin
Seamounts
Underwater mountains that are far away from mid-ocean ridges are called seamounts.
Form when melted rock below the crust pushes it way through the ocean floor and cools.
Volcanic islands formed from seamounts - Hawaiian Islands – Cape Verde Islands (off coast of West Africa)
3 min Seamounts

8. Ocean Composition
6 min plankton
Microscopic organisms that float or drift freely near the ocean’s surface are called plankton.
Phytoplankton – plant-like
Zooplankton – animal-like

9. Ocean Composition Ocean water is salty.
Surface water washes over rocks in rivers and stream dissolving sodium chloride.
Sodium chloride is common table salt.
Desalination is the process of removing salt from sea water.
3 min Desalination
2 ½ min why is it salty?

10. Ocean Waves Ocean water is always in motion.
A wave is a traveling disturbance that carries energy from one place to another.
When wind blows across the water, the wind’s energy is transferred to the water.
As a wave moves, it appears to be moving water forward.
But in reality, the water is moving up and down.
Most waves wash up along beaches. This movement pushes sand along the beach.

11.
6 min - Japan
3 min - Japan
Tsunami
A giant ocean wave that forms after a volcanic eruption, submarine earthquake, or a landslide is called a tsunami.
1 min causes

12.
1 min Bay of Fundy, Canada
3 min tides
Tides
At the shore, the level of the ocean rises and falls during the day.
The tide is the rise and fall of ocean water.
Tides are caused by the gravitational pull of the moon and Sun.
The moon’s gravity causes Earth’s surface water to bulge on the side of the Earth closest to the moon.
Most shores have two high and two low tides.

13. Currents Another kind of ocean motion.
A current is a flow of water in a certain direction.
Warm water flows away from the equator.
Cold water flows towards the equator.
Important current – Gulf Stream (warm ocean current)

14. Causes of Currents
Global winds are the main cause of surface currents.
Differences in salinity (saltiness) causes deep currents.
Earth’s rotation causes currents to move in a clockwise direction in the northern hemisphere.
An undertow is subsurface current near the shore and pulls objects out to sea.

15. 3 min - oceans conservation
3 min  - oceans conservation
4 min - deep sea diving under the North Pole
6 min  - the deep ocean
2 min - the ocean floor
4 ½ min. - Vampire Squid
3 min. - desalination
Cool website
Created by M. Brumbaugh
TCMS