But it's actually the issue of class and economic equality that most interests the teenager, and largely what drove her to make a film exploring the subject from the perspective of her peers.
" 'Everyone says, 'Poverty is this other thing -- that we're all middle class.' We don't talk about class at all. We say that America is a classless society," said Greenberg, whose giggly, high-pitched delivery belies a seriousness that seems well beyond her age.
In May, Greenberg, who attends the Springside School -- an all-girl's private institution in Chestnut Hill -- earned first-place honors for the Philadelphia region for the Princeton Prize in Race Relations. (She already put much of the $1,000 check toward a weeklong community-service program in Costa Rica.)
Overseen by alumni of Princeton University, the prize is awarded in 19 cities throughout the country to high school students who promote "harmony, respect and understanding among people of different races."
The recognition went to the youth's 10-minute film, which explores issues of class through interviews with five young people -- three black, two white -- from different backgrounds, ranging from upper-middle-class to what one subject in the film called "in-between places." While the film does not directly confront the issue of race, the undertones are apparent.
Yet all of Greenberg's interviewees said that they considered themselves middle class, which the young filmmaker found to be an indication that most Americans either aren't conscious of their class status, or choose not to admit exactly where they fit in the spectrum between poor and wealthy.
Dora Lee, co-chair of Philadelphia's Princeton Prize Committee, called the project "an original and creative undertaking that demonstrates [Greenberg's] commitment to opening a dialogue on race and class, both within her community and beyond."
Greenberg, the daughter of Rabbi Julie Greenberg of Congregation Leyv Ha-Ir, "Heart of the City," on Rittenhouse Square, started the film as a Bat Mitzvah project: She was charged with explicating the Torah portion about the jubilee year.
Gail Lloyd, a professional filmmaker and a friend of the Greenberg family, taught Zoe the technical aspects of filming, and then drove her to different parts of the city to conduct her interviews.
'A Teaching Tool'
Another family friend, Felice Yeskel, who wrote Economic Apartheid in America -- which the younger Greenberg read as part of her research -- and who founded Class Action, a Massachusetts-based organization that promotes dialogue on issues of class, attended the Bat Mitzvah where the film was screened.
"When I saw it, I thought, 'This is too useful a teaching tool to be sitting on a shelf,' " said Yeskel, an adjunct professor at the University of Massachusetts at Amherst. "I think the film opens up the possibility that class exits and has an impact on us."
After Greenberg made some additions and edits to the film, Class Action began screening the work and using it for discussion at events around the country.
Greenberg, who will be spending this summer in Massachusetts interning for Class Action, admitted that some people inherently get turned off when she discusses wealth redistribution.
"I think mostly people associate getting rid of inequality with communism, which really shouldn't be how it is," she said. "We should be able to talk about these issues. Before saying that we need to completely change our society, as a first step, we should have a dialogue."