Susie Kay and Dan Wallace found the perfect spot for a civics lesson yesterday, turning their out-of-town high school students loose in Lafayette Park to watch one of America's primary laboratories of democracy.

As their young charges perched on park benches and gawked at a plethora of protesters around them, Kay and Wallace, program instructors for the Close Up Foundation and its week-long student tours of the nation's capital, talked about the nature of political power and persuasion.

"They see these lobbyists in the three-piece suits," said Wallace. "I wanted them to see that there are other types of lobbyists and other ways of making your views known."

Lafayette Park, once an apple orchard and soldiers encampment, has been drawing demonstrators since the days of Jefferson. But the summit meeting between President Reagan and Soviet leader Mikhail Gorbachev this week has inspired an unprecedented gathering of protesters and diverse back-to-back demonstrations.

Directly across the street from the White House, the grassy square is as well-known for colorful protest and unconventional expression as Berkeley's Sproul Plaza or London's Hyde Park. Yesterday's demonstrators vied for space and attention with the so-called regulars, the homeless people and peace activists who spend most, if not all, of their time in the park.

"What makes this four- or five-day period rather special is the diversity of the groups," said Earl Kittleman, chief spokesman for the National Park Service. "Just trying to keep it all straight in our minds, we had to draw a picture of the park and divide it up like a pie."

Protest is not new in this country, and certainly not in Washington.

"This town is always filled with those who want to demonstrate or gather or hold a vigil or make a speech, and the Constitution protects that right," said Kittleman. "It's unusual to have so many groups in the same areas, the park and the Ellipse, but anybody who wanted to be there is there."

Dasha Procyk, her fur hat warding off the morning chill, came from Buffalo yesterday so she could stand in the park and tell President Reagan and the world about Soviet persecution of her Ukrainian countrymen.

"We traveled all night, we'll be here all day and we'll travel back, so you can see how strongly we feel," said Procyk, a member of the Ukrainian Congress Committee of America. "I don't believe the president is standing in the window and watching us, but I think this is the place to be."

Apparently, a lot of people felt the same way.

The demonstrations began at 9 a.m. and didn't wind down until nearly 5 p.m. And they drew a curious assortment of protesters, all intent on drawing the media's attention, if not that of Reagan or Gorbachev.

There were the Afghan students and immigrants, angrily decrying their county's invasion by the Soviets. There was Phyllis Schlafly, of anti-ERA fame, holding up a shredded umbrella and urging the deployment of the Strategic Defense Initiative's "Star Wars" nuclear defense system. There was Bob Kunst, of the Miami-based Cure AIDS, calling for more money and round-the-clock research on the immune system. And there was 69-year-old Amalia Bany, of Bayside, N.Y., wearing her protest signs on a garbage bag pulled over her fur coat and working the crowd hard.

"They're teaching one world," Bany shouted during a debate with one of the Close Up high school students. "That's what the bankers are saying, that's what he's saying," she said, gesturing at the White House.

Bany, a "Mobilize Against Gorbachev" sign sewn to her garbage bag, said her primary purpose for coming to Washington was to protest the signing of any treaties with the Soviets. But she was keeping busy with other causes.

"I was with the Soviet Jews yesterday," she said. "Today, I'm with the Afghans."

At the north end of the park, about 400 supporters of Ukrainian independence watched as black coffins and photographs of maimed children were displayed beside the speaker's platform. A group of schoolchildren sang "God Bless America" and native Ukrainians sang their national anthem while black balloons flew above them.

Several members of Congress, including Reps. Steny H. Hoyer (D-Md.), Lawrence Coughlin (R-Pa.) and Donald E. Lukens (D-Ohio) addressed the protesters, with Hoyer telling them, "Glasnost remains to be realized in the Ukraine."

One woman in the crowd, who yelled out a plea to "Give Gorbachev a chance," was quickly shoved to the back of the crowd.

Some of the protesters directed impassioned personal pleas to the president.

"As a college student in this country, I beg you, President Reagan, don't give SDI away," shouted Joel Garrett, 18. A student at Liberty College in Lynchburg, Va., Garrett wore an earnest face and a Pat Robertson in '88 button, and said he was offended to see the Soviet and U.S. flags flying side by side in the capital of the free world.

For this week's activity, the Park Service adopted stricter regulations on the size and number of protest signs, cleaning out more than 50 permanent billboard-type displays from two summers ago. But there are still about six smaller, but round-the clock, "peace" and "sanity" vigils and demonstrations set up on the south side of the park facing the White House.

Often yesterday, the different protests seemed to trip over each other. As the pro-SDI demonstration ended, for example, the one-on-one debates in its wake delayed the start of the Ukrainian protest. And while the Ukrainians were chanting, a group of Islamic Afghans spread out blankets behind them and began bowing and praying.

At one point an exasperated U.S. Park Police officer, muttering to no one in particular, moved through the crowd repeating, "The SDI group is supposed to be over here and the Ukrainians are over there."

One protester, wearing a sign and carrying another, wandered into the midst of the SDI group and was ordered by a police officer to move away.

"I'm surprised he told me that," said the demonstrator, a former Soviet citizen who is in America now, and didn't budge. "So, it will be one person more -- is it a crime?"