This vocabulary lesson defines 6 words related to underwater exploration of shipwrecks like the Titanic: robotic, interior, cramped, ooze, sediment, and sonar. Robotic means controlled by a computer, interior means inside, cramped means shut into a small space, ooze means soft mud or slime, sediment means material that settles at the bottom of a liquid, and sonar means a device for finding depth or detecting underwater objects.