Such activities contain the elements of project based science in which students "a) construct multiple representations of their understanding b) work on authentic contextualized problems... c) collaborate in a community of learners and d) use cognitive tools to construct and represent knowledge." (Marx, Blumenfeld et al, 1994, pp. 517-518) Typically, students working in teams over several days or weeks employ a variety of solutions to the problems which they are modeling. This frequently requires doing background research (such as finding out how BAC effects reaction rate), performing experiments and gathering data to incorporate into their models. Sometimes the opportunity arises to connect students with an outside mentor from industry, research or a government agency. Students frequently present their results by posting web pages and linking them to project pages from other schools.