Chapter 11, Lesson 3, "Oceans"

Materials:

• Worksheet, Oceans" Terms Review"
• Optional Investigations, "Measuring the Effect of Salt Water on Floating", "Making Fresh Water from Salt Water"

Objective:

• Students will identify two properties of ocean Water.
• Students will explain what causes ocean waves and currents.
• Students will describe several features of the ocean floor.
• Students will identify three major groups of ocean life.

Anticipatory Set:* Students will be shown a box that is 1 meter X 1 meter x 1 meter. They will be asked if it was filled with ordinary sea water how many pounds of salt would remain if the water evaporated? (35 kilograms) If Denali (20,320 feet) was put into the deepest part of the ocean (Mariana Trech, 36,201 ft) would it stick out the top of the ocean or be completely submerged? When you see waves moving accross the ocean it looks like the water is moving. But when a wave moves across the ocean the wave may be moving but the water is not. A human wave at a football stadium is the same thing. People don't move from places to place but the "wave" moves.

Teacher Input:* First lets look at the properties of ocean water. 3.5 percent of ocean water is salt the rest is water. Can the salt be taken out of ocean water? How? The salty ness of salt water is not the same. Remember that the dead Sea and the Great Salt Lake are much saltier than the ocean and even the ocean has different levels of salt. Salt can affect habitat. When an earthquake allowed salt water to soak into this area of Turnegan arm it killed all the trees there. What is the measure of how salty water is called? What is the temperature of the Ocean? Where is it the warmest? How does the temperature different as you go down in the ocean? Temperatures in the ocean change the most 300 - 1000 meters below the surface. What is that area called? (Thermocline)

Next we want to talk about waves. How would you describe a wave? (Wave) What causes waves (Wind). How big is the average wave? (3 meters, the height of the ceiling in your classroom. What is the biggest waves created in storms with strong winds blowing over a long period of time? (30 meters, big wave, this is as tall as the tallest spruce tree you can find) Here are some wave terms, From the top of one wave to the top of the next is the (wavelength). From the top of the wave to its lowest point is the wave height. The lowest point of a wave is called the (trough). A wave breaks near shore because the wave slows at the bottom and remains the same speed at the top this cause it to break.

As we said waves do not move water. The ocean water is moving. What are these movements of the ocean called? If I show you a picture of (how the ocean moves) you may be able to figure out from last chapter what cause them to move. What causes them?(wind) The currents can affect climates because warm water from the equator moves toward the poles and cold water from the poles moves toward the equator (water movement). This cause areas along the ocean to have different climates than areas of the same latitude away from the ocean.

Is the ocean floor flat? There are several areas of the ocean floor that are very different from one another. (The Continental shelf) Slopes genitally from the continent averaging around 130 meters deep and extends out from the continent about 75 kilometers. The (Continental Slope) is an area that dips sharply from the continental shelf to the deeper ocean floor. The Plains of the ocean floor are wide flat areas on the bottom of the ocean. The (mid-Ocean Ridge) is underwater mountain ranges that may or may not be volcanic. The (seamount) is an underwater mountain that rises above the surface of the water to form an island. The Hawaiian Islands are seamounts. A trench is a very deep valley in the ocean floor. Some are nearly 10km deep. The pressure of all the water above that point is about 16,000 lbs/in².

Life in the ocean is grouped into three categories (Ocean life categories) Life that lives very near the surface is called plankton. (Plankton) provides a lot of food for the next group, the (Nekton). The third category is the animals that live on or in the bottom of the ocean and is known as the (Benthos).

Guided Practice:* Students will answer the questions from Page 272 in class.

Independent Practice:* Students will complete the worksheet, "Oceans: Terms Review."

Check for Understanding:* Students will complete the quiz on Chapter 11, Lesson 2 "Oceans".

Duration:

30 minutes + 10-15 for Independent Practice (Could be longer if taken for homework).

Alaska Content Standards Addressed in this lesson:

• SCI A-4 Students will understand observable natural events such as tides, weather, seasons, and moon phases in terms of the structure and motion of the earth (Earth);
• SCI A-6 Students will understand that forces of nature cause different types of motion and describe the relationship between these forces and motion (Motion);
• SCI A-7 Students will understand how the earth changes because of plate tectonics, earthquakes, volcanoes, erosion and deposition, and living things (Processes that Shape the Earth);
• SCI A-9 Students will understand the transfers and transformations of matter and energy that link living things and their physical

• SCI A-15 Students will use science to understand and describe the local environment (Local Knowledge); and: