A large black rock is passed from hand to hand around the classroom. Passing the rock feels like a ritual that's as old as time and is somehow peculiarly appropriate for a class exploring a far-distant era.

It's one of the techniques Robert Thorson uses in his course on earth history, Age of the Dinosaurs. Passing the rock helps bond the group and stimulates curiosity: what long-gone event or series of events pitted the rock's oval surface?.

That's exactly what Thorson hopes for - to engage his students and, by doing so, to promote learning.

"It's very important to pass the rock," Thorson, a professor of geology and geophysics, told an audience of more than 20 faculty members and teaching assistants at a workshop about active learning on Tuesday, sponsored by the Institute for Teaching and Learning. "I don't tell my students what the rock is. That comes later. They have to intuit, feel, otherwise it's a lecture."

Thorson described how, three years ago, faced with teaching a large 100-level course in scientific literacy for non-science students, with few teaching assistants available to help, he restructured the course, supported by a grant from the Institute for Teaching and Learning.

The course he developed, which he has taught for two semesters now, is based on the concept of "active learning." Thorson encourages students to take responsibility for learning, both by being actively involved in class and by pursuing part of the learning on their own outside the classroom.

Recalling the advice of an editor, Thorson said he seeks to "show not tell." He said lectures often focus on telling students information. "The explanation will anchor better if we show the rock first," he said. "We've really got to hold back and let students engage with the subject material," although he does provide the information later. (The rock turns out to be black marble from Alaska..

Thorson said he draws on his experience of having four children and sharing their educational experiences, from preschool to college. "I've derived a lot of my teaching style from (the University's) Child Labs," he said. "I'm trying to move fundamental concepts higher up into the curriculum."

He said that when he developed his curriculum, he looked for "emotional content to help make the material stick. We spend so much time on verbal, auditory experience. I believe in multiple intelligences."

Thorson encourages detailed observation. He sometimes takes all 100 students out of the classroom to the geology park on campus or to the lake. On one occasion he asked his students to observe their own footprints in the snow and make deductions about the size of the individuals who made them, their pace, and so on.

The class still involves two lectures a week, but for the third weekly class, Thorson sends his students out of the classroom to learn on their own - an approach he calls the "break-out model." In sections of about 20, the students rotate through a four-week cycle of a book group, visiting the Museum of Natural History on campus, working independently on the Internet, and meeting with the faculty member.

In each case, the assignments are structured in order to engage the students and encourage them to take an active part.

The book group, for example, reads Dinosaurs of the Flaming Cliffs, an account of a 1993 expedition to Mongolia by the American Museum of Natural History, re-enacting the 1922 expedition that became the model for "Indiana Jones." One of the questions Thorson asks is, "What was your family doing in 1922?" - prompting the students to draw connections between the book, the questions, and their lives.

In the museum, Thorson arranges for a special four week-long exhibit. Students can go there when they want, walk round, and touch the items. "The academic community and the museum are working together to provide education in an informal environment," he said. "That's key. Much scientific learning takes place in an informal environment."

The Internet assignment includes logging on to the paleontology site maintained by the University of California-Berkeley. Another assignment is to search the Web for the best dinosaur material and bring it back to class. "I require them to go there for one hour, and they spend 5 hours. That's really what you want," he said.

Despite the open-ended nature of many of the assignments, Thorson stressed that he holds his students accountable in both the final exam and in a portfolio they must prepare. "The final exam requires answers to questions they can only answer by doing the assignments," he said.

Yet the approach is not a success with every student. Thorson said enrollment in the class has gone down "Many students just want to get the credit, fulfill the requirement," he said. "I'm losing students with no self-initiative.".

But Thorson is not worried. He is convinced that in the new model the majority of students learn more.

"If you demand more of students they are likely to learn more, even though they may not like it," he said. "At this point in my career at UConn, I am more interested in great learning than great ratings." .

Elizabeth Omara-Otunnu