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Adventurous Findings on the Deep Sea Floor

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Adventurous Findings on the Deep Sea Floor Galapagos Rift Expedition AdVENTurous Findings on the Deep Sea Floor FOCUS: visual activity and represents the concept well to the Vent development along the Galapagos Rift students. GRADE LEVEL MATERIALS 5-6 Part 1—For each group of 3 to 4 students: 2 to 3 pictures of hydrothermal vents down- FOCUS QUESTION loaded from the NeMo Explorer website at http: What causes hydrothermal vents to form? //www.pmel.noaa.gov/vents/nemo/explorer.html and www.dive discover.whoi.edu LEARNING OBJECTIVES One copy of the activity entitled “Make Your Own The students will conduct investigations to observe Deep-sea Vent!” formation of precipitates. 1 large glass container, gallon capacity 1 small bottle, 8 oz capacity (or less) The students will create a model of a developing 5 drops of red food coloring hydrothermal vent. A piece of cotton string, I meter in length, cut so The students will generate comparisons between it hangs over the edge of the large container but the created hydrothermal vent model and the does not touch outside surface. actual hydrothermal vents developing along the Cold water (approx. 15 degrees C), enough to fill Galapagos Rift. each gallon capacity container for each group of students ADDITIONAL INFROMATION FOR TEACHERS OF DEAF STUDENTS Hot water (approx. 80 degrees C), enough to fill The words listed as key words should be introduced the small 8 oz. bottle for each group of students prior to the activity. There are no formal signs in American Sign Language for any of these words Part 2—For each group of 3 to 4 students: and many are difficult to lip-read. If some of this 50 ml water information has not already been covered in your 5 ml calcium chloride (Damp Rid, used to remove class, you may need to add an additional class moisture from closets and other damp areas, can period to teach vocabulary and teach some of the be found easily in stores or you can use road salt background information to the students prior to the used to clear roads in the winter) activity. 5 ml baking soda The steps of activities for both days can be written 8 oz clear plastic cup on the board and covered with paper. As each step is done then they can be revealed. This is a very 1 Galapagos Rift Expedition – Grades 5-6 Galapagos Rift Expedition – Grades 5-6 Focus: Vent development along the Galapagos Rift oceanexplorer.noaa.gov oceanexplorer.noaa.gov Focus: Vent development along the Galapagos Rift TEACHING TIME into the ocean as superheated plumes of water that Two periods of 60 minutes each are laced with the minerals of the volcanic rocks below. These minerals are what give the hot water SEATING ARRANGEMENT plumes their color. Groups of 3 or 4 students Hydrothermal vents, etiher shallow of deep, often MAXIMUM NUMBER OF STUDENTS form on the newly-minted hot, volcanic oceanic 30 students crust, which is created during the process of sea floor spreading. The thin, new ocean crust has KEY WORDS cracks in it through which ocean water can seep Hydrothermal vent down to the hotter mantle below. As the ocean Magma water comes in contact with the magma of the Geysers mantle, the energy of the magma is transferred to Rift the water, which becomes superheated. The heated Mantle water molecules are less dense than the cool ocean Molten water, and will begin to rise. The underground Precipitate water also dissolves minerals from the surrounding Chemical reaction magma and rock. As the water rises, it carries the Continental plates minerals from the magma with it. When the heated minerals come in contact with cooler water again, BACKGROUND INFORMATION the energy from them is transferred out and the Rifts and hydrothermal vents offer a real life exam- minerals precipitate and settle to the ocean floor. As ple of how transfer of energy affects solids and the minerals settle they form structures that resemble liquids. Rifts occur on the ocean floor where drift- chimneys with the hydrothermal vent in the middle. ing continental plates are separating. The rift, the Thus, the transfer of energy between magma and area in the crust where the plates separate, creates water creates new ocean floor structures. an opening in the crust where the cold water of the deep ocean is exposed to the Earth’s mantle. The LEARNING PROCEDURE PART 1 (DAY 1): mantle, with an average temperature of 1000°C, 1. Using the Background Information, discuss consists primarily of molten rock and minerals. with the students what hydrothermal vents are When the continental plates separate, the magma and where they are found. Distribute pictures of the mantle rises to fill the gap in the crust. When of hydrothermal vents downloaded from the this molten rock comes in contact with the cold NeMo Explorer website: http://www.pmel.noaa.gov/ ocean water (near 2°C), the energy of the magma vents/nemo/explorer.html and www.divediscover.whoi.edu is transferred to the water, the magma lowers in tem- 2. Explain to the students that explorers from perature, and the minerals in the magma form bonds the National Oceanic and Atmospheric that create new solid rock sea floor crust. Administration, Woods Hole Oceanographic Institution, and other university scientists on Deep hydrothermal vents are underwater hot the Galapagos Rift Expedition are looking springs, yet they are different from the geysers for hydrothermal vents on the bottom of the that often burst out of volcanic areas on land. The deep sea floor. Discuss with the students that great pressures on the bottom of the sea cause the hydrothermal vents release extremely hot difference. This pressure keeps water from boil- water, minerals, and gases from the Earth’s ing. Great pressure also speeds up many chemical crust to the surrounding cold water of the reactions, so deep hydrothermal vents often erupt deep sea. 2 3 Galapagos Rift Expedition – Grades 5-6 Galapagos Rift Expedition – Grades 5-6 Focus: Vent development along the Galapagos Rift oceanexplorer.noaa.gov oceanexplorer.noaa.gov Focus: Vent development along the Galapagos Rift 3. Distribute one copy of the activity entitled 3. Ask the children to identify one person in their “Make Your Own Deep-sea Vent!,” to each group to put the calcium chloride and baking group of students. Ask the students the follow- soda into the 8 oz. cup. ing question: “How can you model the action 4. Ask the children to continue to make observa- of the heated water rising from the cracks of tions and record these observations. hydrothermal vents as it mixes with the sur- 5. Ask the class the following question, “Do you rounding cold water?” observe any changes now that the solids are 4. Provide each group of students with a piece of combined?” Allow the children the opportu- string and red food coloring. Tell the students nity to record their observations and group that each group will be getting cold water to share with the entire class. put in a large glass container and hot water 6. Ask the children to identify someone in their to put in a small container. group to add the water to the two solids. 5. Ask one student from each student group to 7. Ask them to discuss what is happening within come up to the front of the room to collect their group and to record their observations. their samples of hot and cold water. Let the students group share with the class as a 6. Ask the children to follow the directions on whole. Explain that what they are seeing is a their Activity Sheet. The students will record chemical reaction. The bubbles are carbon diox- their results and draw their conclusion. ide gas, which is given off during this reaction. 7. Allow each student group to report their 8. Ask the students the following question, “What results and conclusions to the class as a do you see developing in the bottom of the whole. cup?” Allow time for them to discuss as a 8. Guide the students to recognize that underwa- group, record their observations, and group ter hot springs that are found on the new oce- share with the class as a whole. The children anic crust are formed by the rifts in the ocean should describe seeing a white substance. floor. The thin, new ocean crust has cracks in Explain that the white substance is calcium it through which ocean water can seep down carbonate, and is called a precipitate. to the hotter mantle below. As the ocean 9. Explain to the children that what they have water comes in contact with the magma of observed is similar to the process that causes the mantle, the energy of the magma is trans- hydrothermal vent chimneys to form on cer- ferred to the water, which becomes super- tain regions of the deep sea floor. When heated. The heated water molecules are less the heated minerals dissolved in hot water dense than the cool ocean water, and will begin coming from beneath the seafloor come in to rise. contact with cooler water again, the energy from them is transferred out and the minerals LEARNING PROCEDURE PART 2 (DAY 2) precipitate and settle to the ocean floor. As 1. Have one student from each group come to the minerals settle, they form structures that the front of the room to collect the necessary resemble chimneys with the hydrothermal materials for their group to conduct the investi- vent geyser in the middle. Thus, the transfer gation (See Materials, Part 2). of energy between magma and water creates 2.
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