Ovt suggests that lots of people search for "Volcano science project" related terms. IMO it's a staple school project, kinda classic.
I'm thinking - setup a site with step-by-step instructions on how to do it, allow people to send in their project pics and ideas.
Develop that site they talked about above and I could see $200+ Multiply that by 10 or 20 if it becomes THE goto site for schools and any volcano projects.