On The Ocean Floor

Beach A beach is a sandy or gravelly part of the shore of the sea or of a lake.

Sand Dune A hill or ridge of sand piled up by the wind is a sand dune.

Gravity Gravity is a force that pulls all objects toward each other.

Tides Tides are the daily changes in the local water level of the ocean.

Continental Shelves This is the ocean floor of the shore zone (the place where land and ocean meet).

Continental Shelf All around the edge of the world’s continents, the land slants down and is covered by ocean water. This underwater land is called the continental shelf.

Surface Current A surface current is an ocean current formed when steady winds blow over the surface of the ocean.

Wave A wave is an up and down movement of water.

Storm Surge This is a very large series of waves caused by high winds over a large area of ocean.

Mid-Ocean Ridge This is a vast chain of mountains that runs along centers of Earth’s oceans.

Plateau A plateau is a flat area of land that is raised much higher than the surrounding area.

Fault A fault is a break in the Earth’s crust.

Canyon A deep valley with steep sides, often with a stream flowing through it is a canyon.

Ice Cap An ice cap is a thick cover of ice over an area, sloping in all directions from the center.

Tsunami A tsunami is an unusually large sea wave produced by a seaquake or undersea volcanic earthquake.

Let’s Read! We are going to read and discuss TB pp.D40– D45 now.

The Movements of Oceans Movement Types Waves Tides Currents Surface Currents Deep-Ocean Currents

How do water waves change a shoreline? shoreline by erosion (the carrying away of sediments) and deposition (the dropping of sediments).

What causes deep ocean currents? Water density differences due to differences in temperatures or saltiness cause deep ocean currents.

Let’s Read! We are going to read and discuss TB pp. D48– D53 now.

How is the ocean floor like the Earth’s surface? Both have a variety of landforms, such as plains, mountains, and canyons.

What are some of the products of the shore zone? Fish Salts Rocks Oil

Ocean Facts The oceans of the world are all connected. Together they form one world ocean. There is more water than land on Earth. Oceans cover almost ¾ of the planet! Much of the salt in the ocean water comes from rocks. When rocks are worn down by water, the salt from them goes into the water.

Ocean Facts Sand is formed when rocks break apart and crumble into bits. Each grain of sand is really a tiny piece of rock or shell. When the water near the shore rises and gets deep, it is called a high tide. When the water falls and gets shallow, it is low tide. Tides are caused mostly by the pull of the moon’s gravity on the earth and its oceans.

Ocean Facts Most of the waves we see are caused by the wind. The stronger the wind, the bigger the waves. Is the ocean floor really flat? Flat plains cover much of the ocean floor, but not all of it. The deepest valleys and the tallest mountains on earth are found under the ocean. Why can’t plants grow on the deep ocean floor? Plants need light to grow. It is too dark for plant life on the ocean bottom.

Ocean Facts Parts of the ocean flow like rivers. These moving areas are called ocean currents. Big waves “break” near the ocean shore because in shallow water, the ocean bottom drags on the lower part of the wave and slows it down. The upper part keeps going fast, so it falls over, or breaks.