Brower argued that today's vast array of software for manipulating digital versions of photographic images enables what he calls "photofakery" on an unprecedented scale. He described how editors at National Geographic decided to pull an ad that depicted a polar bear in Antarctica (where there are no bears); the ad had been created by digitally superimposing a photograph of a bear in a Cincinnati zoo and a photograph of the Lemaire Channel in Antarctica. According to Brower, "Too few photographers, I think, appreciate how directly the new technology aims at the heart of the credibility that distinguishes this art form from others."

Credibility is also one of the hallmarks of science. Science progresses as a result of consensus on what results can be expected from carefully designed and carefully executed experiments and observations. As teachers of chemistry, we have a duty not to fall into the same kinds of traps that have made some photographers uneasy about their profession. And we need to help our students learn to avoid these traps. But it is not that easy, because we also need to capture students' attention and try to make our subject interesting by telling stories or showing phenomena or models that appeal to the imagination. As in the case of photography, defining where imagination begins to usurp reality is difficult. It is therefore a very important issue to wrestle with.

Part of Brower's argument against manipulation of images centered on the photograph reproduced here. In 1968, when it was taken by Colonel William Anders of Apollo 8, it galvanized the public's understanding of earth's limited resources by showing an astronaut's view of the isolation and beauty of the earth in a barren cosmos. Brower and others characterize it as "the most important photograph in the history of environmental awareness." The photograph is striking and has not been "enhanced". Anders simply pointed the camera and tripped the shutter, and the result was an excellent representation of what he saw. It supported his description of his experience and helped him to make it known to the vast majority of us who will never make a trip to the moon.

Many of our students and most of the general public are unlikely to penetrate very deeply into the world of chemistry. They are often placed in a position described eloquently by the Dalai Lama, who was asked by a group of scientists whether he accepted the existence of phenomena he had not experienced. He said, "I know the earth to be a round, bluish globe by relying on the words of someone who has seen it and proved it with photographs. You have to rely on a person who has already had this kind of experience and has no reason to tell lies." Having no reason to tell lies certainly ought to characterize scientists and those of us who teach the subject, as should Brower's quotation of Rusty Schweickart, on one of the roles of astronauts: "You are the sensing element for humanity, and that becomes a rather special responsibility."

Indeed scientists and science educators do have a special responsibility, both in discovering new science and in relating the joy and importance of such discoveries to many other people. In doing so, we should be very careful to maintain the credibility without which communication of science becomes impossible. This requires that we have standards that we all agree to follow. As I watch television programs in which there are seamless transitions from photographs or videos of real things to artists' animated conceptions of things that might be, I wonder whether our standards are sufficiently high. The artists' conceptions are seldom labeled as what they are. How is a viewer to tell the difference-especially if that viewer has obtained most of his or her information about science through this same vicarious medium?

This current situation argues strongly for incorporation of real, hands-on involvement of students with science throughout formal schooling. Concentrating on observation and manipulation of materials is likely to be more productive than introducing theories and nanoscale models. As someone old enough to have gotten through elementary school before there was a television set at home, I marvel at the vast array of distractions that separate today's children from real phenomena. Videos, computers, theme parks, the Internet, and various other forms of entertainment are so prevalent that we ought to think very carefully about what kinds of real experiences students have had before they arrive in our classes. It may be that laboratory instruction that expands students' exposure to a range of real, tangible experiences and observations is by far the most important aspect of our courses. Certainly we should pay lots more attention to helping students learn to distinguish observation from explanation, fact from theory, and reality from mental model.