Oceans

By Frank, Danielle, and Anthony M.

Ocean Facts

• Oceans allow many citizens of the world to enjoy a nice, relaxing day in the salty water that is three-fourths of this planet

• About 140 million square miles or 71% of the Earth’s surface is water

• The top ten feet of the ocean contain as much heat as the whole atmosphere

• The average depth of the ocean is more than 2.5 miles

Hydraulic Action

• Hydraulic action is when a wave strikes a cliff face

• The wave striking the cliff face in this action causes the air to compress in the cracks of the cliff face

Weathering

• When water enters the cracks in rocks, the cold season of winter freezes the water in the rocks, causing the rock to break into smaller pieces

• Powerful waves can demolish the rock using the method of hydraulic action

• Rushing water in rivers and streams cause rocks to break because of the force from the water

Natural Disasters

• Some underwater volcanoes that erupt can cause an island to form, like Hawaii (positive and negative)

• An example of a positive affect would be a new island to visit

• A negative example is the eruption could kill many people

The Changing of Earth’s Surface

• The ocean changes the earth’s surface in many ways:

– When an oceanic plate converges with a continental plate, it creates trenches on the ocean floor

– When two oceanic plates converge, it creates underwater volcanoes

Waves

• Formation of Tsunami• Waves are formed when air blows against the

water and then the water is pushed by the wind, creating a wave

• Tsunamis are formed when the fault cracks and the water is propelled forward at high speeds

Questions???

• 1.) How are tsunamis formed?• 2.) How many square miles of the Earth is

water?• 3.) What is the percentage of water on the

Earth?• 4.) What is hydraulic action?• Challenge) Name the two ways the ocean

changes the Earth’s surface.

Answers

• 1.) Tsunamis are formed when the fault cracks, propelling the water forward.

• 2.) 140 million square miles.• 3.) 71%• 4.) Hydraulic action is when a wave strikes a cliff

face.• Challenge) A. Two oceanic plates converge forming

an underwater volcano B. When an oceanic plate converges with a continental plate, it forms a trench.

Reference

• www.noaa.gov/ocean.html• Science.nationalgeographic.com/science/

earth/the-dynamic-earth/weathering-erosion-article/

• Youtube.com/• En.wikipedia.org/wiki/Coastal_erosion• En.wikipedia.org/wiki/ocean