I, robot, one of this summer's sci-fi movie blockbusters, contains a rare moment of meta-narrative, when Will Smith says to his confused boss, "This is just like Frankenstein."

He could have said it was just like dozens of other titles, from Bicentennial Man to Jurassic Park, that exploit the public's vague knowledge of science to tell morality parables.

In the rest of I, Robot, tech-sounding phrases like "positronic operating core" are strewn about to make things sound scientific. It was Isaac Asimov who first suggested that the explosion caused by the collision between an electron and its anti-particle, the positron, might power a robot, but the idea has little scientific basis.

In this summer's otherwise laudable Spider-Man 2, the fusion reactor designed and tested by mad scientist Doc Ock would have melted just about everything on the island of Manhattan. And although it's powered by a plausible fuel (tritium is radioactive and fairly rare), unplugging the reactor, as hero Peter Parker does, wouldn't make a difference – the sun doesn't run on electricity. And as for drowning the reactor underwater, instead of winking out like a Christmas light in January, the ball of plasma would vaporize the East River into a thick cloud of steam.

Like I, Robot, Spider-Man 2 is rife with scientific inaccuracies. But it is, after all, a comic book onscreen and only need tap into vague notions of what science accomplishes to entertain its audience. It's easy to debunk the faulty science in these films. The more interesting question is what these filmic representations tell us about our culture.

When Spider-Man hit the pages of Marvel Comics in 1962, the year the Cold War almost turned hot, public mistrust of science was at an all-time high. The billions of dollars spent on physics and nuclear energy programs were ramping science forward at a pace that made people very uncomfortable. Enter a conflicted science major bitten by a radioactive spider. It's also no surprise that Parker's nemeses are fallen scientists, maniacal obsessives punished for their overzealous pursuit of progress.

In the original Stepford Wives, when a distraught Joanna Eberhart asks the scientist at the men's club why they're replacing their wives with robot clones, he replies "Because we can." The real villain isn't the misogynistic and insecure husband, but science and its lack of a definite moral framework.

"Science centres were to a certain degree a response to that time period," says David Sugarman, senior biologist at the Ontario Science Centre. This summer, Sugarman has developed a program called Disaster Movie Dos And Don'ts, designed to separate the science from the nonsense in popular disaster movies like Twister and Dante's Peak.

"Movies tap into that discomfort people have about the direction of science," Sugarman says, stressing that the hosts of the program try to "focus on developing critical thinking. We want to ask people, 'What's my threshold of credulity?'"

Instead of ruining films by pointing out their weak spots, knowing the truth behind the celluloid can empower us when we're confronted with the real thing.

So if ever you encounter a delinquent robot in a dark alley, don't expect it to have a positronic brain or to bleed blue blood as the humanoids do in I, Robot. Will Smith is, after all, saving the world from caricature robots – or, if you'd prefer, Frankenstein's monster.