For years, Harvard students have dealt with large class enrollments and cavernous, impersonal lecture halls. To some, it has been a blessing--allowing the shy to avoid having to speak in front of their peers, or the tired to catch a few extra winks. To others, the crowding has been but a curse, frustrating and stifling those seeking a little more personal attention.

But, for those enrolled in "Physics 1b," the days of being lost in the crowd are fast becoming numbered.

With the help of a grant from Science Center Director Dean R. Gallant, McKay Professor of Applied Physics Eric M. Mazur is forcing students to learn from each other using interactive systems where technology meets the Science Center's multi-colored halls.

The technology allows Mazur to quiz students immediately to see if they "get it," and allows students to help teach their neighbor--a culmination in Mazur's teaching philosophy of peer instruction.

Start Your Engines

In a scene that seemed straight out of a college admissions video, physics class stopped in the middle of a lecture yesterday as Mazur flipped on an overhead, and told the approximately 160 students, "you have one minute to make up your mind and answer the question."

On cue, students pointed little remote control devices at the front of the room, and personal numbers of the students popped up on the hall's projection screen, recording the classes responses in bright purples, blues, greens, fuchsias and magentas.

Once the minute had passed, Mazur told his class, "turn to your neighbor and see if you can convince your neighbor what the right answer is."

This time, the class broke into their own personal discussions as, again, students entered their new responses into the system.

As the bar graphs which appeared on the hall's video screen instantly showed, the majority of the students had chosen the wrong answer at first; after discussing it with their peers, the class had overwhelmingly corrected themselves and chosen the right answer.

Novel in the sense that students eventually picked the right answer on their own, this exercise also demonstrated something that is all too frequently rare in large science classes: students being forced to interact.

Coffee Talk

Interaction--between the students and the teaching staff, between the students and the professor, and even between the students themselves--distinguishes "Physics 1b" from other science courses.

"I'm really impressed with how hard the professor is trying to make physics more interactive," says Grant P. Christman '00. "It's making it much more interesting."

Indeed, it seems many students share Christman's sentiments. Whereas the "traditional" approach towards teaching large science classes consists of a professor writing equations and topics on the blackboard, Mazur's approach places more emphasis on the students teaching themselves.

To reach this goal, Mazur relied on the concept of peer instruction, a philosophy of teaching large groups of students he has developed over the past decade at Harvard. Rather than just having the professor lecture, peer instruction actively involves students by breaking up brief "mini-lectures" with multiple-choice questions on the topics just covered.

Students think about the question before answering it; afterwards, they then spend a few minutes discussing the problem with their peers before committing to a final answer.

"The idea is simple," says Head Teaching Fellow Christopher B. Schaffer. "You talk to people around you, and chances are the people who got the question right the first time got it right for the right reason, and will be more confident in their reasoning. So, they'll be more likely to convince their peers."

PRS Meets Science Center C

But Mazur's concept of peer instruction would still be a fancy term instead of reality if it were not for the interactive Personal Response Systems (PRS).

Looking like a cross between a phaser from Star Trek and a remote control from Wal-Mart, the input devices allow students to instantly "beam" their answers to a central terminal by pressing a corresponding numerical button. The terminal would then compile the answers and create final distribution statistics for how the class fared on each question.

The units were distributed to students on the first day of class, funded by the science center grant.

For Mazur, PRS is the perfect answer to a perplexing problem. Previous attempts with flashcards and raising hands did not get true responses from students and not all students were participating. Early electronic devices were logistical nightmares to set up and maintain, with their many wires and bulky size.

And PRS also forces students to think twice before they sleep through class. Although they are responsible for bringing their devices to lecture each week, students have added incentive not to forget them at home--since the system records each student's responses, participation in class is counted towards the final grade. As an added catch, random pretests are given at the beginning of class, "to make sure people comes to class on time," Mazur says.

"I'm definitely more motivated now that everything counts," says Rachelle Kier '01.

He Knows When You've Been Sleeping

Mazur has also expanded technology--and accountability--to outside the classroom.

Rather than come to class unprepared, students have to fill out three-question form on the courses web site answering questions from their reading.

The third question, however, is always the same, and asks the student what he or she is having most difficulty with; based on the responses, Mazur then tailors his lecture for the very next day on what students want to hear.

"It's how I try to make the lectures useful," Mazur explains.

In addition, he is able to personally respond to questions--according to head TF Schaffer, the night before yesterday's lecture, Mazur sent out over 100 e-mail messages answering concerns and problems some students were having.

Unique and useful as it may seem, it does require much more effort on the part of students.

"It's hard on students since we have to make it known to the professor what's difficult for us, and not the other way around," Kier says.

Back To The Future

Mazur has been teaching physics at Harvard for 16 years, but it was not until 10 years ago that he realized the traditional approach of lecturing to teach the sciences was not working.

"I was getting extremely high CUE ratings," he says, "and people were doing well on exams, so I thought I was doing it right."

Of the complaints he heard, the most frequent was that he lectured from the book. But according to Mazur, that is what he was doing: he prepared a lecture from the textbook, copied the lecture onto the blackboard during class and watched the students copy what he wrote into their own notebooks--just like most lecturers did at the time.

But he realized when he gave his students what he thought to be a fairly simple exam on basic physics concepts that something was amiss.

"They were doing triple integrals and complex calculus, and I was afraid that by giving them this exam they'd be angry with me," he says. "Not because it was hard, but because it would be so easy."

This wasn't the case, as it turned out the class found the conceptual exam very difficult.

"Apparently, they could jump through the hoops and learned to do the procedures [of physics problems], but never knew the basics," Mazur says.

"They were copying everything into notebooks, but the information needed to be where it counted: in their minds. But it wasn't getting there."

Who's the Teacher?

The year was 1990 when Mazur had what he termed "a crisis in teaching."

He decided to eliminate the information transfer inherent in most lecturing environments, and instead devised a system of teaching based on reading assignments and class involvement.

With funding from the Pew Foundation and then later from the National Science Foundation, he began researching educational techniques that would become his peer instruction philosophy, and applied them to the classes he has taught.

"The point was to teach by questioning rather than telling," Mazur says.

Since his change in teaching style, the main complaint Mazur now hears is no longer that he lectures directly from his notes or from the textbook.

"Rather," he chuckles, "It's: 'Professor Mazur is not teaching us anything--we have to learn it all ourselves!'"

And that, it seems, is his ultimate goal.