Lured by a chance to become a better teacher at a more demanding school, Dan Coast was finishing his first year at Mount Vernon High School in Fairfax County in the summer of 1998, and it was clear to him he was in trouble.

Coast was an emotional man and a very energetic teacher. He had spent the year at Mount Vernon teaching three ninth grade biology classes, plus the two courses that were really testing him, first year International Baccalaureate (IB) biology for juniors and second year IB biology for seniors.

He was 38 years old and had left a comfortable position as a popular science teacher in Charles County, a semi-rural district in Maryland, to step into the IB pressure cooker at Mount Vernon. Having just received his students' disappointing IB test scores, and a very critical evaluation from the IB grading center in Cardiff, Wales, he was beginning to wonder if he had made the right decision.

Most of the commentary about the surge of college-level courses like IB and Advanced Placement (AP) in American high schools has centered on their effect on students. They have added pressure to the school days and nights of many teenagers, as well as given them a chance to earn credits for college and get ready for the demands of university courses. Less has been said about the impact of such courses on teachers, so I think it is important to tell the story of Dan Coast, and what his experience reveals about the unsung courage and pride of many people working in high schools these days.

Coast had wanted to be a teacher since his sixth grade teacher at Hayfield Elementary school in Fairfax County made him feel special by giving him accelerated math instruction. He graduated from Virginia Tech with a degree in biology in 1982, and after a few months working in warehouse, got a teaching job in Charles County. By 1997 he was success at McDonough High School. He taught advanced biology, ecology and regular biology, coached softball, advised the ecology club and the environmental club and had the satisfaction of hearing about many students trying to get themselves assigned to his class.

Joy McManus, chair of the Mount Vernon science department, called him that winter to chat. She had taught at McDonough and liked Coast. He in turn saw Fairfax County, wealthier and higher performing than Charles County, as a step up in the profession. Until that point he had been happy where he was and not thought about moving. But he had had a rough year -- the superintendent had turned down a salary raise and a block scheduling plan he had worked on. He heard himself telling McManus that he might be interested in a change.

"Well, we really do need an IB biology teacher," she said.

He drove over to inspect the Mount Vernon campus. He was impressed, as he expected to be, with the equipment in Fairfax County classrooms. They all had computers and televisions and even a laser projector that allowed him to show molecules and internal organs and other biological representations in a simulated three dimensions. He also liked the greater ethnic diversity. McDonough High was 75 percent non-Hispanic white compared to Mount Vernon's 42 percent, and 36 percent of the students at the Fairfax School were low income compared to only 9 percent at the Charles County school. He was unable to resist the vibrancy and challenge of the IB program. So when they offered him a job, he took it, and managed to get them to match his Charles County salary of $45,000 a year.

He had a week of summer IB training at the United Nations International School, then started to prepare his students for one of the most daunting exams in American secondary education, the IB Higher Level biology test. The exam, given to seniors each May, had three parts, or what the IB people, in the European fashion, called "papers." Paper One lasted one hour and 15 minutes and had 40 multiple choice questions that covered the entire range of the course. Paper Two, two-and-a-half hours long, included experimental questions and were new to Coast. The students were given data charts, graphs and other materials collected from a laboratory experiment, and had to answer series of questions analyzing what they were seeing.

That was the first day of the exam. On the second day they took Paper Three, one-and-a-half hours long. It had seven subject areas, from which teachers could choose two that their students would be tested on. Coast picked evolution and ecology, and prepared them for short-answer questions on both relevant experimental data and related concepts.

This, he told himself, was not going to be easy. He had been working as an educator for 15 years and had developed a reputation for excellence. But those good reviews from students and parents in Charles County had much to do with his energy and pleasant personality. He had never before been forced to achieve such high standards for all his students. Nor had he ever before prepared students for an important test that he did not write or score.

He had had lesson plans at McDonough, to be sure, but no one assessed them and there was no way for anyone to know how well he had prepared his students, except for the few star students who might take the SAT II biology achievement test. He had time at McDonough to coach and advise clubs, but he realized at Mount Vernon that such a light academic schedule was not going to work. He remained in his classroom until dinner time nearly every school night, typing up detailed lesson plans so he could cover everything needed in a 90-minute block schedule class, meeting every other day.

There was so much writing in IB biology. And there were the labs. In his most demanding class at McDonough, advanced biology, Coast had done about 10 hours, and that was not even close to the IB requirements. For the Higher Level course, the IB minimum was 60 hours of labs over two years. The laboratory data analysis questions on Papers Two and Three demanded it.

Yet after putting in all that time, the IB scores for his first class of seniors had been very disappointing. The 15 students averaged 3.8 on the 7-point examination. That was below 4, the minimum score for credit at most colleges, and below the international average score that year of 4.49.

The feedback from the IB readers was brutal. They said he was not covering the syllabus efficiently. They said his students had no understanding of the Krebs cycle, an essential step in the release of energy from sugar and other organic molecules. He read the critique as saying, basically, that he was not doing a good job.

Coast's students had actually done better than the previous year's Mount Vernon IB biology average of 3.36, but he didn't care about that. He felt himself tearing up as he finished his second reading of the IB report. Was he really up to this? When Mount Vernon IB coordinator Betsy Calhoon came by to talk about the results, she could see how upset he was. She was easy on him, he thought. She just said the scores would have to improve. How was he going to do that?

Another year of late nights refining his lesson plans yielded a result that was worse, an average score of 3.42. The first year he could at least entertain the thought that someone else had taught these seniors their junior year, so maybe that teacher was partially at fault. But in his second year the scores were from students he had had both years. Whatever happened was his fault, and no one else's.

And then, very gradually, as he continued to look for ways to improve, he saw he was getting better. More of his students dropped by after school, making small talk and asking for extra help. He was getting them to appreciate the higher standard they had to meet, and putting in the time to meet it.

Last year his students passed the 4 mark, an average score of 4.08 on the exam. His senior course, he realized, had become the most rewarding teaching experience of his life. That group of teenagers provided the fantasy of all good teachers, a class that picked up quickly on what he was talking about and became as excited by a surprising quirk of nature as he was.

In recognition of Coast's hard work and growing sophistication about IB, Mount Vernon principal Cathy Crocker this year made him the new IB coordinator, replacing Calhoon who had retired. "That is the kind of teacher that you want," Crocker said about Coast. "That is the kind of teacher you invest in."

And on Sept. 27, at age 43, Coast became a father, as his wife Beth, a teacher he had met at McDonough, gave birth to Sam and Eliza, twins who made, as far as he was concerned, a very good year complete.

"I grew so much professionally when I came to Fairfax County," he said, "partly due to what the county demanded of me -- the technology, the standards -- but also because of what IB expected of me." So, he said, he plans to stick with it, and raise the standard at Mount Vernon even higher, knowing that this will take the same persistence and patience he showed in his own class.

"Really worthwhile and important things, to be done right, take time," he said.