Have you ever heard the roar of a dinosaur? If you’ve seen any of the Jurassic Park movies, it’s pretty much impossible to forget the bellowing cry of a Tyrannosaurus rex, but did dinosaurs actually sound like that? No one’s really sure. The two closest living relatives of dinosaurs are birds and crocodiles, and they don’t sound anything alike. Did a Velociraptor sound more like a goose or an alligator? Did it even have a voice at all?While no one’s ever heard a real dinosaur, someone behind the scenes had to figure out what they might sound like and then create that sound for the audience by using bits and pieces of the world around us. That’s where sound designers and Foley artists come in, the artists who use sound to bring the unreal to life.If you've watched the end credits of a movie and wondered just what a Foley artist is, and why they're called Foley artists, it all started with sound artist Jack Foley and the 1929 movie Show Boat. Show Boat was meant to be a silent film, but silent movies were already on their way out, and a Broadway musical based on the same book had just made its debut the year before. Producers worried that audiences would not only want sound but would also expect to hear their favorite songs from the musical. With no time to go back and film the movie all over again, they turned to Jack Foley to record a separate audio track, creating sounds like footsteps and raindrops using whatever he could find in the studio. It was the very first film to use what are now called Foley effects, and this technique of creating post-production sound effects is named after him.If you’d like to see a pair of Foley artists at work, creating the sound effects for a movie scene using everything from empty bottles to heads of lettuce, just watch the video below:https://www.youtube.com/watch?v=OONaPcZ4EAsSince there aren’t any dinosaurs to come into the studio and record their lines, sound artists for the Jurassic Park movies faced the challenge of giving voices to creatures that no one has ever heard before. They did this by piecing together all sorts of other ordinary sounds. That famous Tyrannosaurus roar, for instance, is the sound of a baby elephant slowed down and mixed with a growling tiger and a bellowing alligator. Those barking Velociraptors are mostly the sounds of turtles mating, with just a dash of angry geese.Many of the sounds we hear in a movie, even the ones that seem simple enough, are often something quite different. When a legion of Roman soldiers in Spartacus needed to clang dramatically, and it turned out their real armor just sounded like rattling pots and pans, Jack Foley solved it by dangling his keys in front of a microphone. Whenever the sliding doors aboard the starship Enterprise swish open on Star Trek, that’s really just a piece of paper being pulled out of an envelope. And it may be a little harder to see a dramatic kiss in the rain the same way once you know what we’re actually hearing. Check out this short video to find out if you can tell the difference between pattering raindrops and sizzling bacon:https://www.youtube.com/watch?v=OAG8IbNrYboWhat about a whole universe that exists only onscreen? When Star Wars: A New Hope first came out in 1977, it didn’t just revolutionize the visual effects industry: it also made a big impact on cinematic sound design. From droids and lightsabers to TIE fighters and Darth Vader’s mask, sound designer Ben Burtt had to invent all sorts of new sounds that don’t resemble anything we’d usually hear.There’s no mistaking the hum of a lightsaber for anything else, even though we don’t really have lightsabers. That sound comes from a film projector motor mixed with the electric hum of a...