Ithaca, USA - Lenore Durkee, a retired biology professor, was volunteering as a docent at the Museum of the Earth here when she was confronted by a group of seven or eight people, creationists eager to challenge the museum exhibitions on evolution.
They peppered Dr. Durkee with questions about everything from techniques for dating fossils to the second law of thermodynamics, their queries coming so thick and fast that she found it hard to reply.
After about 45 minutes, "I told them I needed to take a break," she recalled. "My mouth was dry."
That encounter and others like it provided the impetus for a training session here in August. Dr. Durkee and scores of other volunteers and staff members from the museum and elsewhere crowded into a meeting room to hear advice from the museum director, Warren D. Allmon, on ways to deal with visitors who reject settled precepts of science on religious grounds.
Similar efforts are under way or planned around the country as science museums and other institutions struggle to contend with challenges to the theory of evolution that they say are growing common and sometimes aggressive.
One company, called B.C. Tours "because we are biblically correct," even offers escorted visits to the Denver Museum of Science and Nature. Participants hear creationists' explanations for the exhibitions.
So officials like Judy Diamond, curator of public programs at the University of Nebraska State Museum in Lincoln, are trying to meet such challenges head-on.
Dr. Diamond is working on evolution exhibitions financed by the National Science Foundation that will go on long-term display at six museums of natural history from Minnesota to Texas. The program includes training for docents and staff members.
"The goal is to understand the controversies, so that people are better able to handle them as they come up," she said. "Museums, as a field, have recognized we need to take a more proactive role in evolution education."
Dr. Allmon, who directs the Paleontological Research Institution, an affiliate of Cornell University, began the training session here in September with statistics from Gallup Polls: 54 percent of Americans do not believe that human beings evolved from earlier species, and although almost half believe that Darwin has been proved right, slightly more disagree.
"Just telling them they are wrong is not going to be effective," he said.
Instead, he told the volunteers that when they encounter religious fundamentalists they should emphasize that science museums live by the rules of science. They seek answers in nature to questions about nature, they look for explanations that can be tested by experiment and observation in the material world, and they understand that all scientific knowledge is provisional - capable of being overturned when better answers are discovered.
"Is it against all religion?" he asked. "No. But it is against some religions."
There is more than one type of creationist, he said: "thinking creationists who want to know answers, and they are willing to listen, even if they go away unconvinced" and "people who for whatever reason are here to bother you, to trap you, to bludgeon you."
Those were the type of people who confronted Dr. Durkee, a former biology professor at Grinnell College in Iowa. The encounter left her discouraged.
"It is no wonder that many biologists will simply refuse to debate creationists or I.D.ers," she said, using the abbreviation for intelligent design, a cousin of creationism. "It is as if they aren't listening."
Dr. Allmon says even trained scientists like Dr. Durkee can benefit from explicit advice about dealing with religious challenges to science exhibitions.
"There is an art, a script that is very, very helpful," he said.
A pamphlet handed out at the training session provides information on the scientific method, the theory of evolution and other basic information. It offers suggestions on replying to frequently raised challenges like "Is there lots of evidence against evolution?" (The answer begins, simply, "No.")
When talking to visitors about evolution, the pamphlet advises, "don't avoid using the word." Rehearse answers to frequently asked questions, because "you'll be more comfortable when you sound like you know what you're talking about."
Dr. Allmon told his audience to "be firm and clear, not defensive." The pamphlet says that if all else fails, and docents find themselves in an unpleasant confrontation, they excuse themselves by saying, "I have to go to the restroom."
Eugenie C. Scott, who directs the National Center for Science Education and is conducting training sessions for Dr. Diamond's program, said that within the last year or so efforts to train museum personnel and volunteers on evolution and related topics had substantially increased. "This seems to be a cottage industry now," Dr. Scott said.
Robert M. West, a paleontologist and former science museum director who is now a consultant to museums, said several institutions were intensifying the docents' training "so they are comfortable with the concepts, not just the material but the intellectual, philosophical background - and they know their administrations are going to support them if someone criticizes them."
At the Denver science museum, the staff and docents often encounter groups from B.C. Tours, which for 15 years has offered tours of the museum based on literal readings of the Bible. The group embraces young-earth creationism, the view that the earth and its plants, animals and people were created in a matter of days a few thousand years ago.
"We present both sides from an objective perspective and let the students decide for themselves," said Rusty Carter, an operator of the group.
Mr. Carter praised the museum, saying it had been "very professional and accommodating, even though they do not support us." A typical group might have 30 or 40 people, he added.
Kirk Johnson, a paleontologist who is the chief curator at the museum, was philosophical about the group. "It's interesting to walk along with them," he said.
Participants pay the admission fee and have as much right as anyone else to be in the museum, Dr. Johnson said, but sometimes "we have to restrain our docents from interacting with them."
John G. West, a senior fellow at the Discovery Institute, whose researchers endorse intelligent design, said he was not aware of organized efforts to challenge museum exhibitions on evolution. He added, "It is not unheard of for museum exhibits to be wrong scientifically."
Dr. Scott, who trained as a physical anthropologist, said that in training docents she emphasized "how the public understands or misunderstands evolution and some of the misconceptions they come in with." She hopes to combat the idea that people must choose between science and faith - "that you are either a good Christian creationist or an evil atheist evolutionist."
"It's your job," she told docents, "not to slam the door in the face of a believer."
At the American Museum of Natural History, which is about to open what it describes as "the most in-depth exhibition ever" on Darwin and his work, curators and other staff members instruct volunteer "explainers" on the science behind its exhibitions, according to Stephen Reichl, a spokesman. If visitors challenge the presentations, the explainers are instructed to listen "and then explain the science and the evidence."
Sarah Fiorello, an environmental educator at the Finger Lakes State Parks Region who took part in the Ithaca training session in August, said she was now prepared to take the same approach. When she describes the region's geological history on tours of its gorges, visitors often object - as even a member of her family once did - that "it does not say that in the Bible."
Now, she said, she will tell them, "The landscape tells a story based on geological events, based on science."
Dr. Durkee also said she found the session helpful. "When you are in a museum, you can't antagonize people," she said. "Your job is to help them, to explain your point of view, but respect theirs.
"I like the idea of stressing that this is a science museum, and we deal with matters of science."