She answered the ad, spent the next three years teaching science in a bleak South Bronx middle school and altered a life trajectory that until then had been pointed toward a career in biotechnology and law.
Seven years later, the 29-year-old Palo Alto High School graduate finds herself at the heart of an education reform movement that is shaking up classrooms in low-income areas across the country.
Bobel, the executive director of Teach for America's Bay Area organization, oversees a "corps" of 400 young teachers on scores of public school campuses, plus an alumni network whose members are occupying principals' offices, launching their own schools and running for school boards.
The former competitive figure skater expresses a visionary's zeal for her cause eradicating educational inequality and little patience with skeptics.
"We think we're different," Bobel said of Teach for America, which last year nationally attracted more than 40,000 applications from college seniors including many from top-ranked universities for 4,500 entry-level teaching jobs in some of the worst-performing schools across the country.
"We think we bring really energetic, vision-driven, deeply passionate individuals, and beyond that it just comes down to effectiveness," she said.
Often criticized for dropping fresh-faced, inexperienced college grads into some of the nation's toughest classrooms and displacing credentialed teachers Teach for America asserts that, on balance, it achieves superior results.
Academic studies have yielded mixed results on Teach for America's effectiveness, and a lively debate continues among scholars.
But Teach for America has been embraced by influential big-city school superintendents, including Joel Klein who headed New York City's public schools from 2002 until last week, and Michelle Rhee, herself a Teach for America alum who led Washington, D.C.'s public schools from 2007 to 2010.
Bobel maintains that the intense summer training, youthful commitment and near round-the-clock work ethic of Teach for America recruits give disadvantaged students a teacher who will go the extra mile to make sure they learn. Corps members are regularly flooded with data about how their students are performing, and asked to adjust their approaches accordingly.
"Data shows that the average growth in one year for kids in low-income communities is 0.4 to 0.5 years. They're mastering about half of the content they should be mastering, so that's why the achievement gap widens," Bobel said.
"By eighth grade, low-income students on average are three grade levels below more affluent peers.
"We've got to overcompensate because they're growing up in poverty. Teach for America aims for 1.5 years of growth in one year triple the average growth currently going on in our schools.
"We need to put many more great teachers in front of our kids, working relentlessly. This is just hard work," she said.
TFA corps members are measured individually on their students' progress, with mixed results.
Beyond the two- to three-year teaching commitment required by Teach for America, Bobel said many Teach for America alumni remain in Bay Area schools as teachers and principals, infusing their reformist mentality into mainstream school systems.
The organization holds a philosophy of "teaching as leadership," aiming to recruit corps members with leadership potential who will advocate for school reform whether they remain in education or ultimately go into other fields.
"What great educators and visionary principals do is similar to what a great CEO would do: set an ambitious goal, invest people around the goal; plan milestones to get to the destination and not just deliver the material, but make sure the kids are where they need to be," Bobel said.
Of 1,300 Bay Area Teach for America alumni, 54 are now principals in area schools, both traditional and charter schools. Another 300 have continued in long-term teaching careers.
In East Palo Alto's Ravenswood City School District, two principals are Teach for America alums.
"We've been in the Oakland Unified School District for 20 years and now 12 percent of the principals in Oakland are TFA alums," Bobel said.
"We need more leadership at the principal level, great visionaries who know how to develop their teachers."
Even among the Bay Area Teach for America alums who move on to careers outside of education, more than half contributed their time or money to the organization last year, she said.
"When all school districts are challenged by budget cuts, it comes down to the extent to which superintendents and principals see Teach for America as adding value and something that can truly move the needle," she said.
"I have a superintendent (in San Jose) who says, 'Whatever budget decisions I have to make, I'm not going to sacrifice TFA.'"
Bobel's own three years of teaching in a beleaguered, South Bronx middle school were an eye-opener for her.
"It was a stark contrast to Jordan Middle School, where I went.
"There were two sets of metal detectors, barbed wire all over the windows, no grass, no blacktop, no joy it looked like a prison."
Bobel was one of five Teach for America corps members on the school's faculty of 50, encountering "a culture of unbelievably low expectations, negativity, lack of organization within the school, with kids literally running up and down the halls.
"And our task was to create an island of excellence, high expectations and learning in this sea of chaos."
As an 8th-grade science teacher, Bobel said she became scrappy, borrowing or stealing resources from any source she could find.
"At that time in Silicon Valley, a lot of the dotcoms were going under and they had extra supplies. We shipped 150 binders from here to my classroom, so all my kids had binders second semester," she said.
At one point, Bobel found herself reduced to grabbing handfuls of the small, half-pencils from the plastic boxes at IKEA.
"My kids didn't even have pencils I didn't even have chalk."
She borrowed a module approach used in her undergraduate human-biology studies at Stanford, teaching units on HIV and substance abuse that were relevant to her students.
She signed up her classes for the U.S. Department of Energy's Minority Outreach Initiative and had students build fuel-efficient model cars in preparation for a visit from a U.S. assistant secretary of energy.
She held after-school hours and Saturday schools. By the end of eighth grade, 123 of her 125 students scored at or above grade level on a comprehensive science test.
"It wasn't easy by any stretch, but my kids were just as talented as any set of kids in Palo Alto. They're just not given the resources or the attention, and no one has the expectation they can succeed. The minute you change that mindset and conditions, the kids are going to rise to it."
Bobel said it is "not obvious" even to her how she ended up so passionate about education reform.
When she chose Teach for America over the biotech job out of college, she recalls that her parents and friends told her, "'You're not cut out for this.'
"The more people told me I was crazy, the more it made me determined," she said.
"I was never the smartest, or the best athlete growing up. But I firmly believed that no matter where you start from, hard work can land you on top of the heap, and that mindset still continues to drive me.
"I grew up confused by the stark differences in education opportunities between Palo Alto and East Palo Alto.
"I knew something wasn't right, and my desire to do the corps stemmed from wanting to impact this and make a positive difference in our country."