Teacher Resources American Museum of Natural History Black Smoker Expedition Activity 1 Leaving Your Mark Suggested age group: grades 7-12 Goal: To become aware of the human impact on the environment. Also to think about tools and engineering solutions to minimize this impact. Objective: Students apply the scientific method in order to discuss human impact on the black smoker environment. Students also brainstorm solutions for minimizing this impact. Materials: paper and pen/pencil; optional: on-line access to black smoker Web site bulletin board area Terms (defined in Web site glossary): submersible, ROV Start the discussion by asking students for some examples of human impact on the environment (trash, tundra affected by a footstep, etc.). Pose this problem to students: Currently ROVs and submersibles carry extra weights that enable them to sink to the ocean floor. When the research is completed and it is time to return to the ocean surface, the weights are dropped. This lightens the ROV or submersible, enabling it to float back to sea level. Scientists are still looking for a solution that would not involve leaving the weights behind. Next, discuss some preliminary questions to get students thinking about whether the weights that are left behind are a problem. Students will apply the scientific method to the problem. € What information would you need to know to make an educated decision about the human impact on this underwater environment? € How could we measure the environmental impact? € Can we develop a question or experiment to answer our question of what is the human impact on this underwater environment? € How many labs or trials would need to be performed to get a true picture? € Have we picked a measurable variable to plot that isn't related to many other variables? Brainstorm some creative ideas for getting a submersible from the ocean floor to sea level without leaving weights behind. Ask students to write and illustrate their solution ideas. Students could even create models of their ideas and simulate the floating from seafloor to sea level in a large fish tank filled with water. Optional: Have students post their ideas for minimizing human impact on this undersea environment on the bulletin board area of the black smoker Web site. This electronic board will allow students to debate this topic with students around the country and people around the world.   Activity 2 To ROV or Not to ROV Suggested age group: grades 7­12 Goal: To think about the resources involved with research and to understand a current events debate on human versus robotic expeditions. Objective: To use a classroom discussion as a vehicle for generating questions about human versus robotic science exploration. Materials: paper and pen/pencil; optional: on-line access to black smoker Web site bulletin board area Terms (defined in Web site glossary): submersible, ROV Start the discussion with some preliminary questions to get students thinking about what resources are in the context of scientific exploration: What does the word efficient mean when you are talking about scientific research? € How do scientists get money to fund their research projects? € Is the money a limited amount? € Since resources are limited, meaning they can get used up, does that mean if we use them for this that they won't be available for other projects? € What responsibilities or obligations do scientists have if they receive money from the government or a company to perform research? € What is the difference between an industrial scientist (such as for a pharmaceutical company) versus an academic scientist (at a university)? € Who has more resources, industrial scientists or academic scientists? € How important are the research outcomes? € Should we be concerned about research for the sake of solving a mystery or answering a question? What about research in order to make a profit? At this point give students the assignment below. This can be done in small groups or as a class: Remember the ROVer that landed on Mars? Deep-sea ocean research has many parallels to space research. The ocean floor and outer space still hold many mysteries for scientists, and both involve expensive research equipment. Submersibles allow scientists to dive to the ocean floor but are much more costly than ROVs. ROVs can stay underwater longer than submersibles. Create a list of the pros and cons for both human and robotic scientific exploration. Consider limited resources such as grant money. Do you think NASA and other scientific expedition funders should spend the money to include people on explorations, or allow remotely operated vehicles to perform research? What do you think is the most efficient way to use scientific research money? Optional: Have students post their final arguments for human versus robotic research on the bulletin board area of the black smoker Web site. This electronic board will allow students to debate this topic with students around the country and people around the world.   Activity 3 The Claw Suggested age group: grades 7-12 Goal: To think about tools and engineering in the context of the black smoker expedition. Objective: To design a tool for collecting a black smoker. Materials: paper and pen/pencil; optional: on-line access to black smoker Web site bulletin board area TERMS (defined in Web site glossary): submersible, ROV Pose this problem to students: The mechanical arm found on submersibles and ROVs is used to collect samples from the seafloor. Much like the claw in an arcade game, the mechanical arm helps collect a black smoker for further scientific study. The mechanical arm is not strong enough to break the black smoker off by itself. Neither a submersible nor an ROV can lift the sample back to the ocean surface. Design a tool or procedure to break off the black smoker sample you need and raise it to the surface. Remember that an ROV takes approximately two hours to return to sea level from the seafloor. Generate a list of considerations with the class before they begin their group designs: € What materials will their tool be made of? € Describe how your tool moves mechanically. € Describe how the tool functions: how it drives, does it use a tension cable, etc. € How does the tool handle temperature changes? Remember, the black smoker can reach up to 400 degrees Celsius and is going to come into contact with very cold seawater. € Does your tool minimize impact on the environment? € Estimate the cost of building your tool. Optional: Have students post their tool and engineering ideas on the bulletin board area of the black smoker Web site. This electronic board will allow students to share their ideas with students around the country and people around the world.   Activity 4 How Old Is It? Suggested age group: grades 4-12 Goal: To learn how the surface of Earth grows and changes, specifically how oceanic crust forms and ages. Objective: To create a legend for the spreading map that shows older crust farthest from the ridge system. Materials: crayons, colored pencils or markers; printout of black-and-white Global Age Contour Map Terms (defined in Web site glossary): zero-age, oceanic crust, subduction Have students review the World Ridge System, especially the Spreading section, of the black smoker Web site before starting this activity. You can download the text of these Web pages if computer access is an issue. Students will select four colors and create an age legend for their map: zero-age (gray already marked) 0 to 30 million years 30 to 60 million years 60 to 90 million years older than 90 million years For the following discussion questions, make sure students explain their answers: € How is the age of "new earth" described? New earth is considered to be zero-age (formed within the last 10,000 years). € Is new earth really new? It is new earth, but the minerals have always been there below the ocean floor (see Black Smoker Animation on the Web site). € How does this "new" earth form? The plates spread apart at ridges, causing cracking of the oceanic crust. Magma from Earth's mantle below rises into these cracks and cools. Older crust is moved away from the ridges as new crust is created. This ongoing process results in an expanded surface area (see Black Smoker Animation on the Web site). € Is the oldest crust closest to the ridge, or farthest from the ridge? farthest € As you move toward older oceanic crust, does the depth increase or decrease? (See bathymetry map on the Web site for clues.) It gets deeper farther from the ridges. € What happens to seafloor when it collides with a continent during spreading? It's subducted, which means it sinks below the continent into Earth's mantle. Scientists don't know precisely what happens after that. Some think that the oceanic crust sinks all the way down and piles up at the mantle-core boundary. Others think that the oceanic crust breaks up and is stirred back into the mantle. € Spreading rate varies from 1 to 20 centimeters per year. Which ridge, the Pacific or Atlantic, is spreading faster? Compare the amount of spreading (distance from gray, zero-age crust to the 30-million-year age contour) at the Pacific Ridge west of South America to the amount of spreading at the Atlantic Ridge east of South America in order to answer the question. the Pacific ©1997, American Museum of Natural History