This lists the logos of programs or partners of NG Education which have provided or contributed the content on this page. Program DEEPSEA CHALLENGE

  • Tips & Modifications

    Modification

    As an alternative to using a water column built from soda bottles, you can use a 3 meter (10 foot) length of 10 cm (4 in) wide PVC, capped at the bottom. 

    Tip

    As students test in deeper water, they may need to increase the amount of foam used or decrease the amount of items they initially used for weight (such as coins) to maintain buoyancy under increasing pressure. They may also make adjustments to increase the amount of air in the design.

    Tip

    Decrease your preparation time by enlisting students to help cut the bottles for the water column. 

    Tip

    Hand-held PVC pipe cutters can be used to cut PVC pipe to whatever length necessary. Consider pre-cutting the pipe into 5 cm (2 in) segments for students. For safety reasons, do not allow students to handle the pipe cutters.

    Modification

    If you have access to an existing body of water at least 3 meters (10 feet) deep, such as a swimming pool, you can test the prototypes there instead of constructing the water column. Be sure to create submersion and retrieval tools that match the depth of the water.

    Tip

    Increase students’ motivation by turning the trials at 3 meters (10 feet) into a competition. Award one point for each second that it takes a prototype to return to the surface. After all groups have completed their testing, offer prizes for the highest score and the most improved score.

    Tip

    Keep safety in mind while testing with the water column. One person will need to be able to reach the top of the 3 meter (10 foot) water column in order to launch the prototype. Consider drafting an adult helper for this role. If possible, locate the water column near an outdoor stairwell or tall playground equipment, such as a slide. If necessary, use a ladder to reach the top of the water column, and the water column can be attached to the ladder for stability.

    Tip

    Rather than using the tall water column for testing in 1 meter (3 feet) of water, you can use a smaller container, such as a large trash can. This could make it easier for students to get the prototypes into and out of the water and could allow multiple teams to test at once.

    Tip

    Some groups might finish steps 3 or 4 early. Have these teams create a retrieval rod to rescue any prototypes that get stuck in the water column during testing. These rods must be able to retrieve a capsule from up to 3 meters (10 feet) of water. For example, students might bend a coat hanger into a hook and attach it to the end of a long piece of bamboo or ½-inch PVC pipe.

    1. Activate students’ prior knowledge by having groups share their brainstorming ideas from Activity 3: Under Pressure: Creating a Model for adjustments they will make to keep their submersibles slightly positively buoyant at different depths.
    Have students bring out the Engineering Process handout from the previous activity and refer to it as they share their brainstorming notes. Have groups keep the handout handy.

    2. View and discuss the "Charting the Course" video.
    Provide students with the following focus questions prior to viewing the video: What factors did James Cameron and his team consider when selecting their testing location? What made their choice of location unusual? What made it a good choice? Have students use these questions to take notes during the video, and use the questions to launch a discussion at the end of the video.

    3. Review the testing procedure for deep-water tests.
    Explain to students that they will conduct a series of deeper-water tests on their prototypes at depths of 1 meter, 1.5 meters, and 3 meters (3 feet, 5 feet, and 10 feet). Distribute the Deep-Water Testing Rubric and review it with students to make sure they understand what is expected of them in this activity. Then, per step 6 of the Engineering Process handout, have students review the testing procedure and data table they used in the shallow-water tests in the Under Pressure: Creating a Model activity.

    4. Have students adjust their prototypes in preparation for the deep-water testing.
    Give groups time to make adjustments to their models at this point based on their ideas from brainstorming in the Under Pressure: Creating a Model activity. Remind students to document any changes they make.

    5. Have students test the prototypes in 1 meter (3 feet) of water.
    Give each group an opportunity to test their model three times at a water depth of 1 meter (3 feet) using the water column described in the How to Create a Water Column handout or an alternative container. Students should use a pole to submerge their prototype to a depth of 1 meter (3 feet) and then remove the pole to see what happens to the prototype. A negatively buoyant prototype will sink; a neutrally buoyant prototype will hover at 1 meter (3 feet), and a positively buoyant prototype will rise to the surface. The slower a positively buoyant prototype rises, the closer it is to neutrally buoyant. As students test their prototypes, have them record their data during each test, including the time it takes their prototypes to rise to the surface. Between tests, have students evaluate their results and determine any changes they want to make to their prototypes to improve their performance. Have students make any changes to their prototypes and record the details of those changes in their tables before testing again.

    6. Have students test the prototypes in 1.5 meters (5 feet) of water.
    After students have completed the round of testing at 1 meter (3 feet), ask them to consider differences they encountered between testing at 1 meter (3 feet) and testing at 30 centimeters (1 foot) during the shallow-water test in the previous activity. Ask: What factors were different at the new depth? Did these factors significantly affect how the prototypes worked? How might these factors change at a depth of 1.5 meters (5 feet)? Have students repeat the testing process at a depth of 1.5 meters (5 feet) using the water column. Again, make sure they record detailed data for each of the three tests, including any adjustments made to their designs.

    7. Have students test the prototypes in 3 meters (10 feet) of water.
    Explain that students will have three opportunities to test and adjust their models at the target depth of 3 meters (10 feet). Their third test at this depth will be their final test. Have students review their testing data from the previous tests and consider what factors will be different in 3 meters (10 feet) of water from factors in 30 centimeters (1 foot), 1 meter (3 feet), and 1.5 meters (5 feet) of water. For example, a prototype that is positively buoyant at 1.5 meters (5 feet) might or might not remain positively buoyant at 3 meters (10 feet) due to compression of foam pieces from the increased pressure. Have students list these factors, along with how they might affect the functioning of the prototypes. Have students make and record any adjustments to their prototypes to address these factors before beginning the final set of tests. Have students repeat the testing process at a depth of 3 meters (10 feet) using the water column. Again, make sure they record detailed data for each test, including any adjustments made to their designs. Have students note their best time for this set of tests. The best time would be the slowest time for the prototype to rise to the surface from a depth of 3 meters (10 feet).

    8. Have students write detailed deep-water testing reports.
    Have students use their data from testing to document changes they made to their prototypes during the testing process and to explain why those changes were necessary. Have students use numerical data, such as the time it took the prototype to rise to the surface, to describe the changing conditions they encountered and the adjustments they made and why. Have them describe the effects of pressure on their models and how they dealt with those effects.

    9. Have students revise their original concept drawings based on the testing process.
    Have groups return to their original concept drawings from the Under Pressure: Defining the Problem activity. Ask: Is there anything you would change about your original concept based on the testing you conducted on your prototype? Have students revise their concept drawings to make any adjustments based on the testing they have done.

    10. Discuss the process of modeling, testing, and revising.
    Give each group a chance to brief the class on their testing results. As a class discuss the overall testing process. Talk about what worked well and what didn’t work as well. Discuss the following points: What adjustments did groups make, and why were these adjustments necessary? How did the necessary adjustments differ among groups? What factors might have caused these differences?

    11. Explore the DEEPSEA CHALLENGE team’s design process and solution.
    Have students read about and discuss the solution James Cameron and his team came up with to solve the problem with the foam on the provided DEEPSEA CHALLENGE: Systems and Technology website. View and discuss the "Contingency Plans" and "Systems Failure" videos. Provide students with the following focus questions prior to viewing the videos: What went wrong during the final dive? How did these issues affect the plans for the dive? What adjustments did the team make to address the problem? Have students use these questions to guide their note taking for each video. Then use the focus questions to open a discussion about the videos. Ask: Are you surprised that the DEEPSEA CHALLENGE team encountered these problems after spending so much time and money to design and test the submersible prior to the final dive? How does this reflect the nature of engineering challenges? As a class, discuss any similarities between students’ engineering experiences in this activity and the expedition team’s engineering process and experience.

    Alternative Assessment

    Use the Deep-Water Testing Rubric to assess students’ testing reports.

    Extending the Learning

    Have groups exchange submersible models. Challenge each group to adapt the model they receive to remain neutrally buoyant in 30 centimeters (1 foot) of water. Discuss why this is more challenging than adjusting the model to be positively or negatively buoyant.

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