WASHINGTON (Reuters) -- A vote by the Kansas Board of Education to remove evolution from the school curriculum represents a new tactic by religious activists frustrated by court rulings against them, experts said Wednesday.

Similar such attempts are likely to continue in the United States where, despite the legal separation of church and state, religious sentiment runs deep, the experts added.

"Whenever there is a court ruling ... you see people looking at the language of the ruling to see if there is way to get around it," said Molleen Matsumura, network project director of the National Center for Science Education.

The Kansas education board's vote means individual schools can continue to teach evolution in science classes, but it removed evolution from the required curriculum. Knowledge of evolution will not be needed to pass state-sanctioned tests.

"The creationists are remarkably inventive in finding new ways to attack evolution and new ways to subvert the authority of evolution in the school curriculum," said Christopher Toumey, cultural anthropologist at the University of Kentucky.

Several federal court rulings have struck down similar attempts in other states to force schools to teach that a god created the world, and everything in it, in one fell swoop.

In 1968, the U.S. Supreme Court ruled that an Arkansas law prohibiting the teaching of evolution was unconstitutional under the First Amendment, saying teaching must not be tailored to the principles of any particular religious group.

Arkansas lawmakers later passed a law requiring schools to give "balanced" treatment to "creation-science" and "evolution-science" but in 1982 a federal court struck down the law, saying "creation-science" is not science at all. This did not stop neighboring Louisiana from passing a "Creationism Act" that banned the teaching of evolution in schools unless "creation science" was also taught. In 1987, the Supreme Court ruled the act endorsed religion.

"It seemed in 1987 when the Supreme Court ruled in the Louisiana case that creationists were going to be pretty much frustrated," said Toumey, who wrote about the creationist movement in his book "God's Own Scientists".

Instead, they redoubled their efforts. "It's pretty impressive, the various ways, almost guerrilla tactics, that they have used to get around that," he added. "There's never going to be any final resolution to this."

In 1995, Alabama passed a law mandating that all biology books used in public schools bear a sticker describing evolution as a "controversial theory".

Mainstream scientists say this is twisting the definition of the word "theory." "In the popular mind, if something is only a theory then it's somehow less true," Toumey said.

"In scientific terms, 'theory' does not mean 'guess' or 'hunch' as it does in everyday usage," the National Academy of Sciences said in a statement. "Scientific theories are explanations of natural phenomena built up logically from testable observations and hypotheses."

When scientists use the word "fact" they mean "something that has been tested or observed so many times that there is no longer a compelling reason to keep testing or looking for examples," it said. "Evolution in this sense is a fact."

Creationists have also recruited scientific methods to promote their ideas.

The Institute of Creation Science (www.icr.org) supports research aimed at showing conventional science is wrong and that the Earth and life on it are in fact much younger than scientists say, a conclusion in line with Biblical writings. Matsumura said she worried about the ruling's effect on the children of Kansas. "Their scientific literacy will be seriously damaged and unfortunately scientific literacy in this society is not all it should be." Polls support this, and show many Americans believe in creationism.

A recent survey by the National Science Foundation found that 52 percent of adults believe early humans lived alongside dinosaurs, 65 percent do not believe the Big Bang theory, and 55 percent do not believe that humans evolved from animals.

A poll done in June by the Gallup organization found that 68 percent of the more than 1,000 Americans surveyed wanted both creationism and evolution taught in the classroom, but 55 percent opposed teaching creationism instead of evolution.

A 1993 Gallup poll found that 47 percent of those surveyed believed humans were created by God 10,000 years ago, 35 percent believed humans evolved earlier but God directed the process, and just 11 percent believed evolution occurred without the involvement of a deity.