Question: When the swimmers are running out of the water, why does Brody shout: "No whistles?"
raywest
20th Feb 2009
Jaws (1975)
Answer: When the shark attacks fist began, Brody began reading up on shark behavior. It is believed that vibrating sounds can attract sharks. Brody believes that multiple people blowing loud whistles could bring the shark closer into shore.
On the contrary, high frequency noises (such as those produced by whistles) barely penetrate into the water and seem to have no effect on sharks or any other fish. Low-frequency noises (such as concussive splashing) travel a great distance in water and are a definite attraction for marine predators. Ultra-low-frequency noises (such as the songs of whales) can travel hundreds of miles through water. The U.S. Navy even uses extremely-low-frequency (ELF) transmissions for communicating with submarines far out at sea. So, no, there is no documented scientific reason for Brody to think that high-frequency noise would attract sharks. Either the movie's screenwriters were badly mistaken in their assumption that whistles attract sharks, or the character of Chief Brody was deliberately written to be mistaken in that assumption.
In a study, sharks were attracted to low-frequency pulsed sounds resembling those of struggling fish. Sharks appearing in close to wounded or struggling fish has often been observed by fishermen and scuba divers. That type of shark behavior is probably what Brody read about, though his scientific knowledge or understanding about it was limited. He was just reacting in an excited manner.
7th Aug 2014
Jaws (1975)
Question: The other night me and some friends were arguing whether or not the shot that Brody makes to blow the tank up to kill Bruce was possible, or would it be too hard to make?
Chosen answer: It would certainly be very difficult, with the shark moving and hitting the tank while slightly underwater. But it wouldn't be impossible.
Answer: This theory was tested on "Mythbusters" and the myth was "busted", twice. https://mythresults.com/mythbusters-vs-jaws.
Answer: Brody didn't want to panic all the beach goers and cause a splashing commotion which would excite the shark.