1. Make basic comparisons between two deep-sea exploration vehicles.

Display the provided images of the Trieste and the DEEPSEA CHALLENGER side-by-side. Explain that these two vehicles are the only vehicles to have carried humans to the deepest known place in the ocean, the Challenger Deep in the Mariana Trench. Ask students to make observations about the similarities and differences between the two vehicles in the images. Ask: Which do you think is older? Which do you think was able to descend and ascend more quickly? Which do you think weighs more? Make sure students provide reasoning to support their answers. Distribute the Then and Now: Comparison Table handout and have students look at the table comparing the two vehicles. Review the statistics on the handout while viewing the images. Ask students to identify which vehicle is the Trieste and which is the DEEPSEA CHALLENGER based on the statistics listed in the table. For each statistic in the table, ask students to point out specifics from the image that indicate or explain the statistic.

2. Briefly explore the history of ocean exploration using the Ocean Exploration GeoStory.

Divide students into pairs and direct them to the provided Ocean Exploration GeoStory. Have students explore the GeoStory to get an overview of some significant events in ocean exploration. After about ten minutes, discuss what students have learned. Ask: What surprised you about early ocean exploration? What were some limits on early ocean exploration? How have scientists and explorers overcome those limits? What roles have technology and advances in technology played in ocean exploration? How has ocean exploration changed over time?

3. Have students identify constraints and considerations of deep-sea exploration vehicles.

Introduce the concepts of constraints and considerations to students and give examples of each. Constraints are absolute requirements or limitations in a design or decision-making process. If a choice or solution doesn’t meet the constraints, then it must be eliminated. For example, if you are shopping for new bookshelves for your living room, there will be a size constraint. The bookshelves must be small enough to fit in the available space in your living room. Any bookshelves that are too big must be eliminated as a choice, even if they are otherwise perfect. Considerations are desired, but not necessary, elements in a design, solution, or decision. Considerations can be used to rank choices and solutions. For example, if your living room has a lot of dark wood, the tone of the wood for your bookshelves would be a consideration; you may prefer to have dark wood so that it will match the other wood in the room. However, you wouldn’t necessarily eliminate a shelf just because it has lighter wood. Ask students to work with their partners to brainstorm and record constraints and considerations for deep-sea exploration vehicles. For each item they list, have students explain why they categorized it as either a constraint or a consideration. After a few minutes, have pairs share their ideas with the class. Create master lists of constraints and considerations on the board. Discuss whether or not other students agree with the way items have been categorized, and adjust the lists as necessary.

4. Have students research specific deep-sea exploration vehicles.

Explain that students will conduct research to explore how the constraints and considerations they identified are addressed differently in the designs of different vehicles. Divide students into three groups and assign each group one of the following deep-sea exploration vehicles to research: Trieste, Alvin, or DEEPSEA CHALLENGER. Distribute the Vehicle Information worksheet to each student. Have students use the provided websites to do some basic research about their assigned vehicles, working individually or in pairs, and to complete the first two sections of the worksheet. Have students compare notes with others in their group.

5. Have students research individual systems of their assigned vehicles in more detail.

Explain that deep-sea exploration vehicles are complex and include a number of different systems working together in order to fulfill the vehicle’s purpose. Within each of the three vehicle groups, assign a system to individuals or pairs for further research. Assign the following systems: the manned chamber, buoyancy control, navigation, research tools (including arms, video, viewports, etc.), communication technology, and power. Explain that students must become the experts within their groups on their assigned systems. Have students continue their research and complete the Vehicle Information worksheet with details about their systems, including their purpose, how they work, and how they connect to the purpose of the vehicle as a whole.

6. Have all the experts on each system discuss their system together.

Have students form new groups, one for each system. Each system group should be composed of three members—the experts on that system for each of the three vehicles. Have students share information with their new group about how the system worked on their assigned vehicle. Have groups identify similarities and differences in their assigned system among the three vehicles. Also have students identify the constraints and considerations of deep-sea exploration that their system addresses and discuss how the system addresses each one. Ask students to take into consideration when each of the vehicles was built and how the designs of deep-sea exploration vehicles have changed over time. Have each system group briefly present their findings to the class. 

7. Have students compare the three vehicles in their original vehicle groups.

Have students return to their original vehicle groups from step 4. Distribute the Three-Circle Venn Diagram to students and have them label each circle with the name of one of the vehicles the class researched. If necessary, briefly review how to fill out a Venn diagram. Have students work collaboratively to complete the Venn diagram using each other’s expertise on the various systems within the vehicles in their comparisons.

8. Discuss the activity’s guiding questions.

Ask students: How do individual systems within a deep-sea exploration vehicle work together to fulfill the purpose of the vehicle? How have the individual systems changed over time? Encourage students to provide specific examples from the vehicles they researched to support their ideas.