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March 22, 2007

Change how science is taught, Nobel laureate urges

“We need a new, more effective approach to science education. And I think approaching it the way we approach science offers that hope,” a Nobel laureate told listeners at the School of Arts and Sciences spring teaching excellence lecture.

In introducing Carl Wieman, a University of British Columbia physics professor, Regina Schulte-Ladbeck, A&S associate dean of undergraduate studies, noted that Americans have grown accustomed to leadership in research, science, technology, engineering and mathematics and take for granted the prosperity that this world leadership affords. “Yet, the majority of Americans are scientifically illiterate.”

She added that teachers struggle to find ways to raise the level of preparedness of students who are illiterate in science, technology, engineering and mathematics; to raise society’s knowledge of science, and to increase the numbers of students entering these important fields.

Noting that there are no simple answers, she said changing the way science is taught may be useful.

Wieman posits that while science itself has advanced rapidly in the past 500 years, science education has remained essentially medieval.

Wieman, who won the 2001 Nobel Prize in physics, most recently has devoted himself to the study of science education. He joined the University of British Columbia in January as a professor of physics and head of its science education project. He retains an appointment at the University of Colorado at Boulder as head of a science education project there.

“When you get a Nobel Prize, you suddenly become an expert on everything,” Wieman told his audience at the March 14 event, urging them to judge his presentation on the supporting data rather than his background.

Citing two major societal changes — that a scientifically literate populace is necessary in order to make wise decisions on the technical global issues humanity faces, and that the modern economy now is based on science and technology — Wieman said that the purpose of science education has changed.

“I’d argue that it is profoundly different from the historical purpose of science education, which was really to train this tiny fraction of the population who were going to become the next generation of scientists,” he said.

“We can’t just worry about the people who are going to be the next generation of scientists and engineers. They’re still important but we really need to make science education effective and relevant now for the large fraction of the whole population.”

Key to the success of science education is a transformation of students’ thinking, “so they think about and use science more like a scientist would,” he said.

“Look at some of the basic fundamental practices at the heart of how we do science research. Practices based on objective data, not tradition or anecdotes or superstition that drives a lot of teaching practice,” he said.

Using research on how people learn, disseminating results in a scholarly way, copying what works and using available technology can be powerful if utilized in science education, he said.

Wieman admitted that when he began teaching, he approached the task by figuring out the subject matter in his head, then explaining it very clearly — expecting that students would then pick up the information with the same clarity he had.

It didn’t work. “For the great majority of the students, they were just baffled by this,” he said.

In contrast, in observing his graduate students, he discovered a pattern: “These students would come in to work in my research lab and they’d have 17 years of spectacular success in their course work … but they’d come in to do research and they were just so clueless as to how to do physics research and oftentimes, it seemed to me, clueless about what physics even was.” After they’d spent a few years in the research lab, “I’d suddenly realize, ‘Gosh, these people are expert physicists.’”

That sparked his voyage into the research on how people learn and, more specifically, how people learn science, in order to make sense of what he was observing.

Citing examples that show traditional science lecturing is not the most effective way to develop students’ information retention and conceptual knowledge or enhance the correct beliefs about science and problem-solving skills, he urged professors to take another look at how they teach science.

Drawing from cognitive science research, Wieman said short-term working memory has an extremely limited capacity. “Laboratory studies show the human brain can hold something like seven distinct items and the brain can process four ideas at once. This is just a tiny amount of capacity compared to what the human brain is called upon to retain and process in a typical science lecture,” he said.

“I would argue it is very fundamental brain processing that dramatically limits the information transfer that’s going to happen in our lectures.”

In short, he said, “Reducing cognitive load improves learning. A good picture to have in thinking about students is that if you give the student a mental equivalent of one package to carry, they can make a lot of progress in a hurry. If you load them down with a bunch of packages all at once, they stagger around and have a lot more trouble and can’t get as far. And if you do the mental equivalent of dumping a whole lot of packages on them all at once, you just mentally squash them flat. They can’t really process anything.”

He urged professors to slow down, and to make the organizational structure of their lesson clear so students see how it fits together and can anticipate what’s coming next. He also suggested using figures and illustrations rather than explaining something out loud, so students don’t have to translate the words into a mental image.

Cutting jargon also helps, he said. If a new term is introduced, professors need to think about its importance in relation to the amount of short-term memory it will take up. “It’s really important to remember that if there’s some technical term — even if you explain it very clearly — if it’s not in their long-term memory you just used one-seventh of that precious capacity because every time you refer to it, they have to think through and access it in their short-term memory to make sense of the subject,” Wieman said.

He urged professors to recognize the importance of students’ beliefs in the area of science being taught. “Teaching practices affect student beliefs,” he noted.

It would be expected that physics students start as novices and leave class as experts, but the opposite has been found to be true. Research shows that “Nearly all introductory physics courses make the students more novice-like in their beliefs after taking the class than they were when they started,” he said.

Novice thought is characterized by the belief that content is a collection of random, isolated bits of information that must be learned by memory, that are handed down by a disconnected authority and that are not related to the real world, Wieman said.

“To a novice, problem-solving means you just memorize formulas and recipes and then you kind of match the problem you’re given to this memorized recipe.”

At the other end of the spectrum is expert thought, which is characterized by believing that physics is a coherent structure of concepts that are established by experience to describe nature. To the expert, “Physics problem-solving is about using these concept- based strategies, which are very widely applicable,” he said.

Experts have a lot of factual knowledge about their subject, a unique organizational structure of how they file and retrieve information effectively and the ability to monitor their own thinking in the discipline, Wieman said. “They’re able to figure out ‘Do I understand this? How can I check?’” The assumption that these skills come along as students acquire factual knowledge doesn’t match what research shows. “These are really new ways of thinking” that require focused mental effort to construct, he said.

Avoiding that shift toward more novice-like beliefs is simple, Wieman told the audience: “It’s just recognizing and explicitly addressing these beliefs.” In the process of teaching, “make sure that you address why is it worth learning, how does it connect to the real world, why does it make sense … and how does it connect to the things the student already knows? If you do nothing more than that, you will see a significant impact,” he said.

“The principle is really well-established that people really learn by creating their own understanding and that good teaching is really just a facilitation of that creation,” he said. “First you’ve got to get people really involved in thinking about the subject and then you’ve got to find out how they’re thinking, monitoring it in some way and then guiding it to be more expert-like.”

That’s exactly what students in the research lab are doing, he said: exploring, thinking and getting guidance.

“It’s not that there’s something magical about the research lab, it’s the cognitive processes that are going on there,” he said, adding that traditional science instruction for many students “is like trying to produce houses by sitting there telling them about building as opposed to giving them hammers and nails and some guidance on how to build stuff.”

Wieman also said that not enough thought is given to homework, noting that extended effortful study is required to develop the long-term memory that characterizes science mastery. “This is biology,” he said. “The brain needs to build up the proteins that make up long-term memory and there’s no way to make that happen in a one-hour period. You really need to be thinking at least as much if not more about designing effective homework problems than you do in what goes on in the actual classroom.”

The size of modern science classes requires technology to enhance teaching, Wieman said. He touted the proper use of student response systems, more commonly known as “clickers,” and interactive computer simulations.

It’s important to think about what the technology can provide, he said. Clickers make students accountable for their answers, offer anonymity (eliminating peer pressure) and allow a fast response, Wieman said.

Still, students often perceive them as an expensive way to take attendance and give pop quizzes, sometimes breeding resentment. “You really have to think about how you can use them to enhance engagement of the students and communication so that you can get more rapid, effective, targeted feedback and therefore enhance learning.”

One project Wieman has been leading for many years is the development of interactive simulations for teaching physics (and now chemistry) available free online at

Among them is a lesson in static electricity that uses a depiction of a balloon and a sweater, showing the positive and negative charges and how they align when the student uses the mouse to “rub” the balloon on the sweater.

Another demonstrates the often-difficult concept of graphing motion over time by using the image of a running man atop the graphs that depict his progress.

“We see these can be really powerful tools for helping students learn,” he said, citing how research has shown that students using a computer simulation to design a simple electrical circuit actually scored better on related final exam questions than students who used real wires, switches, batteries and light bulbs.

Studies emphasize several points that are important to keep in mind when trying to develop effective teaching strategies, he said. “Students aren’t just uninformed, they really think and perceive differently than experts do. … They really develop their understanding when they’re engaged in asking themselves questions, playing with the simulation so they’re engaged and then there’s feedback to guide their thinking.”

Wieman said that teaching science the way scientists approach science not only is more effective, “It also makes teaching a lot more fun. Because it not only tells you how to make students learn more, but it also tells you how to make them more interested, more motivated, more engaged.”

—Kimberly K. Barlow

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