The most remarkable special effect in this movie based on Ray Bradbury’s classic science fiction short story is Ben Kingsley’s hair. The usually-bald actor has been given a thick thatch so white it almost glows in the dark. He even has a little white soul patch under his lip. Now that’s scary.

It is set in Chicago in the year 2055. Kingsley plays Charles Hatton, who happily admits that his ambition is to own pretty much everything. He runs a time travel tour that takes wealthy people looking for thrills on a five-minute visit to the late cretaceous era, where they get a chance to kill an allosaurus before they come back to champagne and a 3-D recording of their big adventure.

Dr. Travis Ryer (Edward Burns) works for Hatton because it permits him to pursue his own research on extinct animals — pretty much every non-domesticated species, which all died out due to a virus. Ryer is confident that the protocols they have set up will ensure that nothing in the past will change, because even the slightest interaction with the past could create a variation with massive consequences for the present, 65 million years later. The allosaurus they kill was about to die anyway, and they shoot it with bullets made from water, leaving no residue of the future.

But, as another scientist expalains, the Heisenberg uncertainty principle a sort of cosmic Murphy’s law tells us that nothing is ever fool-proof. One of the clients makes a mistake, and when the group returns to the present, time waves, like a temporal sonic boom, bring about massive evolutionary changes. Ryer and his group have to figure out what happened and then go back again to prevent it as the city crumbles around them and huge predators from an alternate evolutionary chain chase after them.

This is an excuse for a lot of racing around and a lot of CGI, all of it pretty standard and unimaginative. The characters are dull, the actors all seem to wish they were somewhere else, and some of the special effects get downright silly. Keeping up with each wave of changes as they come through is more trouble than it’s worth. Sound of thunder? More like the whine of a petulant lapdog.

Parents should know that this movie has a great deal of action-style violence and intense peril, including scary-looking monsters and poisonous plants. A character commits suicide. It also includes brief strong language, social drinking, some sexual references, and a sexual situation with implied nudity.

Families who see this film should talk about the meaning of the butterfly effect. What kinds of controls can we put in place to prevent scientific advances from being exploited for short-term gains?

Families who enjoy this film will also enjoy Jurassic Park and some of the other movies that play with the idea of the way changing past events can affect the present, like the Back to the Future trilogy and the underrated Frequency. They may also enjoy Grand Tour: Disaster in Time. And everyone should read Ray Bradbury’s original influential and very fine short story.