An American physicist is calling for Hollywood producers to tone down the fanciful science in movies - and restrict themselves to just one scientific flaw per film. But which are the worst offenders when it comes to bad science films

Film characters disappear into thin air, travel through time, and know how to fly. They're all scientific impossibilities, but since they take place on the silver screen, we suspend our disbelief and go along for the ride.

But one scientist has had enough and is calling on filmmakers to temper their creativity by obeying the rules of science.

At a recent meeting of American scientists, physicist Sidney Perkowitz suggested a new rule: every film should be allowed just one major suspension of belief for the sake of the story.

In other words, films shouldn't repeatedly violate scientific laws. And they definitely should avoid internal inconsistencies - breaking scientific rules established in earlier scenes.

"If it's scene after scene, it becomes greater than I can stand," says Mr Perkowitz. "I understand the dramatic impulse behind it. The natural tendency is to hype things up."

Others in the scientific community agree.

In order to emphasise a sense of "impending doom", filmmakers often ignore realities like time, says David Kirby, a lecturer in science communications at University of Manchester. After all, if the asteroid in Armageddon was spotted years before it threatened to hit Earth, the story would lack tension.

"Errors of time scale are often done for narrative purposes," says Mr Kirby.

And for those who think the rules of the laboratory have no place in cinemas, Mr Kirby points out movies often tap into contemporary attitudes towards science and can shape people's thoughts. That's why recent films have focused on things like genetic engineering, the environment, epidemics, and the end of the world.

But Steven Le Comber, an evolutionary biologist at Queen Mary, University of London, is at pains to point out scientists don't always make bad movie-going partners. While he does notice "bad science" in films, particularly when it's in his own subject area, it doesn't necessarily ruin his film-going experience.

"If it's a good enough movie, I'll let them do it," he says. "Science is ruined by bad science, not bad movies."

So which are the worst offenders

DEEP BLUE SEA (1999)

Starring: Saffron Burrows, Samuel L Jackson

The plot: A team of scientists find a cure for Alzheimer's disease using a protein found in sharks' brains. So to harvest more of the useful protein, they create a breed of super-intelligent sharks - their intelligence meaning they have lots of brains - which promptly attack the scientists' underwater lab.

Silliest science moment: A scientist sticks a syringe directly into a shark's brain, extracts some cells, places them under a microscope, and watches as the cells regenerate... complete with computer-generated sparks. "When we're talking about neurons firing, there's not any actual lightning," notes Mr Le Comber.

What should have been: Chemicals from one organism - usually plants - have been known to have either therapeutic or toxic effects on other species. But even if scientists were able to isolate and identify an Alzheimer's-curing protein in sharks, they would need to grow it in a controlled environment. The solution might be to raise the protein in a bacteria, in large vats in a laboratory, in a way similar to how the first synthetic human insulin was created.

The lab-based solution would eliminate the epic battle with the sharks - and be "not quite as exciting", Mr Le Comber admits. And any scientist knows that such a procedure would entail extensive research and requests for funding - a lengthy process overlooked by the film's rogue scientists.

Does it matter: "It doesn't give an accurate idea of what scientists do," Mr Le Comber says of the film. "But I don't think science fares any worse than any other occupations."

THE 6TH DAY (2000)

Starring: - Arnold Schwarzenegger x 2

The plot: In the year 2015, a man returns home on his birthday, only to find that a clone has replaced him. The double was created, unbeknown to the original man, using only a blood sample and "memory" capture. The film's ultimate showdown takes place between the two Arnies.

Silliest science moment: Cloning living organisms is difficult enough, but the man behind the "illegal" cloning also pulled off a scientific first by cloning a dead person (his wife). While noting this supposedly romantic gesture to be "a little bit creepy" Mr Perkowitz's main beef is with the science. It may also lead people to believe they can die and easily have their DNA harvested and cloned, he fears. In reality, DNA is fragile and quickly degrades after death - a point that even the fantastical Jurassic Park had nailed, a full seven years earlier. In it, the dino-DNA had to be preserved in sap.

What should have been: Since the film takes place in the future, it gets a bit more flexibility in terms of plausibility. But still, "the idea that clones come out fully formed with memories is ludicrous," Mr Kirby says. As it happens, Mr Perkowitz has flexed his own creative ambitions - penning a screenplay in which DNA is extracted from a person, inserted into a human egg, and born via "normal" means - rather than creating a "totally realised" human being. Hollywood, however, has yet to come knocking at his door.

Does it matter: "Because films reach more people than almost any other media, it has real societal impact," Mr Perkowitz says. He thinks incorrect depictions of cloning can contribute to public fear and suspicion of genetic engineering.

THE CORE (2003)

Starring: Aaron Eckhart, Hilary Swank

The plot: When Mother Earth's molten core stops spinning for unknown reasons, a team of scientists must go to the centre and detonate a hydrogen bomb to get it to spin again. The fate of mankind rests on it.

Silliest science moment: When the crew reaches the Earth's centre and disembarks, their leader only breaks a slight sweat. But anyone who found themselves within spitting distance of the Earth's real core would find "instantly vaporise", Mr Perkowitz says.

What should have been: The whole idea that the Earth's core would stop spinning is implausible, chimes Mr Kirby. The film would do well to build on the moment when the scientist uses a peach - skin, flesh, and stone - to represent the Earth's three layers, says Mr Perkowitz - a minute-long scene that he concedes is OK. But "they get every other scientific fact wrong," he says.

Does it matter: The film is so bad, Mr Perkowitz thinks "it's almost deliberately wrong just to irritate the scientists in the audience." He rates it as Hollywood's worst science film.

Add your comments on this story, using the form below.

This article is from the BBC News website. © British Broadcasting Corporation, The BBC is not responsible for the content of external internet sites.