If it is not possible to build multiple ROVs with students, one ROV can be used for demonstration purposes. For example, in a year in which I could not get funding for multiple kits, I used one I had already built, attached a GoPro camera to it, and allowed my students to use it to explore different water depths in the Blue Hill Bay in my hometown.
If building one ROV is not possible, there are incredible resources about using ROVs for ocean exploration at www.nautiluslive.org
During the dive season, it is possible for students and the general public to interact live with ROV pilots during dives happening from E/V Nautilus.
When explaining ROV technology and its scientific applications, I always remind myself to "start at the beginning." Although many people are aware of ROVs, they are often unaware of how they work and where they are used. The topic is interesting to small children and adults alike, particularly when they have an opportunity to view footage taken from an ROV.
WHOI scientist, Dr. Christopher German, recently used an ROV to explore hydrothermal vents in the Arctic Ocean. He was recently featured in Popular Science magazine: http://www.popsci.com/chris-german-underwater-geochemist-explorer
His work is particularly groundbreaking and may help scientists predict what life forms may exist around hydrothermal vents of the frozen seas of Europa, a moon of Jupiter!