San Diego, California (CNN) -- Television shows and movies may take you to worlds far away, but their makers, aware of viewers' need for believability, say they consult scientists to make things more real.

"Audiences now demand that, or they hunger for it," Academy-Award winning director and producer Ron Howard said at this weekend's meeting of the American Association for the Advancement of Science. "They want it to ring true whenever possible."

Scientists and entertainment professionals are finding each other through recent initiatives.

Howard promoted one called the Creative Science Studio, a new partnership between the National Science Foundation and the University of California School of Cinematic Arts.

Another is the Science and Entertainment Exchange, a National Academy of Sciences program, which gives entertainment professionals access to top scientists.

Howard's film "Angels and Demons" features the world's largest particle accelerator, the Large Hadron Collider. Scientists helped with an opening sequence, designing graphics and making it generally more plausible, Howard told scientists and journalists at the meeting.

"I think Hollywood's attitude will be, if we can make it more realistic without spoiling the story and without it costing too much more money, we will do it, but there are always those restraints," said Sidney Perkowitz, Emory University physicist and author of "Hollywood Science."

Given that worldwide box office sales for "The Day After Tomorrow" eclipsed sales for the global warming documentary "An Inconvenient Truth" by nearly $500 million, science-fiction films play a powerful role in reaching large numbers of people and spreading awareness of issues such as climate change, Perkowitz said.

"Avatar" and "District 9," both current Oscar nominees, reflect real issues of science and society, such as genetic engineering, he said.

"Gattaca," a 1997 futuristic thriller dealing with the effects of putting too much faith in the knowledge of humans' DNA, is a good example of science in film, Perkowitz said.

The 2003 disaster movie "The Core," on the other hand, is full of inaccuracies, such as the Earth's "electromagnetic" field (it's magnetic) and faulty details about the inner structure of the planet, he said.

"That film seems to me to be contemptuous of science," Perkowitz said. "Ignorance is excusable. Contempt is not excusable."

Perkowitz and other experts said they allow for one or two suspensions of disbelief -- faster-than-light travel, for instance -- before they start critiquing based on established science.

The hit TV show "Lost" is full of mystery and fantasy but is actually logical in its portrayal of time travel in the first five seasons, said Sean Carroll, a physicist at California Institute of Technology and author of "From Eternity to Now."

Although there is no time machine -- lights flash, and the characters go back decades -- it plausibly assumes that the past must stay intact and cannot be changed by the time travelers, he said.

"I think that that is a very respectable way to think about time travel; that is what it would have to be like," said Carroll, who is also a guest on a "Lost" Season 5 DVD extra.

Mistakes in movies can be teachable moments, Perkowitz said.

The movie "Starship Troopers," featuring 10-foot tall bugs, fails the test of logic for Perkowitz but serves an important lesson.

He did the math and realized that if the bugs on which the giant creatures were modeled -- about an inch long and one ounce in weight -- were scaled up, they would weigh about 108,000 pounds.

"The science was wrong," he said. "Evolution would not allow this to happen."

Entertainment writers say they do sometimes knowingly violate reality.

Aron Coleite, writer and producer for the TV hit "Heroes," said the show's team knew it's false that humans use only a small fraction of the brain. But since a large portion of viewers believe this to be true, "it allowed them to believe kind of the more unbelievable things that happened on the show," he said.

The show's producing team also spent hours discussing how to depict invisibility: Should the characters' skin be invisible? Should they be naked while invisible?

They finally decided on "an invisible field around them that distorts the light" to explain why the characters retain their clothes, although this is not explicitly stated, Coleite said.

Although "Heroes" could offer a better explanation for evolutionary changes that occur, it does bring up issues of free will and genetic predisposition, said Nicole King, a biologist at the University of California, Berkeley. These are particularly important today as modern medicine is able to identify genes that portend high risk for certain diseases.

"In a very nice way, it demonstrates that the code is not enough," she said of the show. "There is the role of the environment."

One day, Perkowitz joked, perhaps there will be a movie that includes the disclaimer, "No scientific concepts were seriously harmed in making this film."