Tomorrow's leaders debate today's challenges at World Affairs Seminar

While some high school students were grilling hamburgers in fast-food restaurants, tanning on the beach, or cruising Main Street with their friends, more than 650 students chose to take part June 19-24 in the seventh annual World Affairs Seminar.

The purpose of the seminar, according to its founder and general manager, Dr. Dale Brock, is to ''help these young people to better understand world problems. These are future world leaders, and hopefully they'll learn to settle problems peacefully instead of through armed conflict.''

The week-long program, held on the spacious University of Wisconsin-Whitewater campus, about 100 miles north of Chicago, brought together 150 foreign students representing more than 50 countries, along with 500 top American high school students, mostly from the North Central region. Most of the students were sponsored by civic organizations - Rotary, Kiwanis, Lions - and many were chosen after rigorous local competition.

Khaled Sheta, an Egyptian exchange student who spent the last year living and attending school in Iowa, said the seminar gave him a chance to learn more about world problems.

''I really didn't know much about El Salvador before this week,'' he said.

An exchange student from England, Mark Brady, who also spent the last year in Iowa, liked the opportunity to exchange views with American students, but added: ''Some of them get very upset when we try to criticize the United States. But we Europeans believe that the US will only use Europe to place its nuclear missiles , and then use it as a battle theater.''

Some of the students at the seminar saw a split between the American and foreign students, with the Americans holding much stronger anticommunist views.

''You've been brainwashed since you were born,'' said one foreign student.

Virtually all of them agreed, however, that the week demonstrated that world problems are terribly complex, that students from other countries are very much like themselves, and that armed conflict is something to be avoided at all cost.

One participant, after listening to the views of the people seated around her , sighed and said, ''We get along so well. If the world could just be like that.''

Later in the week the students heard from Gary Guertner of the US Army War College, Dr. George Stanford of the Argonne National Laboratory, Anne Nelson of Canada's Maclean's Magazine, Juan Mendez of ''Americas Watch,'' and Charles Shapiro and Dr. Kenneth Peoples of the US State Department, and others.

After each presentation the students were free to ask questions, and more often than not their depth of knowledge took the speakers by surprise.

''They've been swarming around us, asking questions that I've found thoughtful and excellent,'' said George Black, from the North American Congress on Latin America. ''Some are thinking and talking like graduate students.''

Mr. Black added that the students are very skeptical about the Reagan administration's foreign policy. He said he also found them ''very open, not at all relying on the stereotyped views of the world.''

Although the morning sessions were lively, the discussion groups that followed a lunch break were often livelier. In one group, for example, the wisdom of isolationism was debated vigorously. So was America's relationships to its allies.

''I don't want to offend anyone,'' said an American student, ''but Japan and Germany haven't paid back their war debts (to the US).''

Another student suggested that America should just ''get out of El Salvador, '' but a student from Norway objected.

''I live in Norway, and we're right next to Russia. You don't know what it's like, because you live in America,'' he said.

''The United States just pushes its big nose into everything, and then it can't get out,'' said an Israeli student. ''We thought we'd just go into Lebanon , get the PLO out, and then get out. Now they're dependent on us for police action.''

Dr. Brock started the World Affairs Seminar in 1977 as a project of Rotary District 627, representing 51 Rotary clubs in southeastern Wisconsin. The first seminar drew fewer than 150 students, but it has grown in numbers and popularity ever since. This year's total is the largest so far.

The academic coordinator for the seminar, Dr. Charles Cottle, who teaches political science at UW-Whitewater, said he chose this year's speakers to represent ''all ranges of the political spectrum.''

''The primary purpose of the seminar is educational,'' he explained. ''But it's also a week-long experience of living with students from many different countries.''