– How do divers dive from like 170 some feet in the air and have zero damage, but if someone jumps off the Golden Gate Bridge, they are probably going to die.
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When you hit water from a dive the forces on you are related to how fast you decelerate on entry to the water, and the rate you decelerate is related to how fast you’re going when you hit the water. More speed = more force = more injury.
The Golden Gate Bridge is about another ~70 feet higher than the world record high dive.
The additional speed you pick up from that additional fall distance is enough that the deceleration forces upon impact with the water become high enough that even an ideal dive would result in severe, and life threatening, injuries.
The force involved here is because the faster you hit the water the faster you have to accelerate a volume of water about equal to your own volume and push it out of the way to make space for your own volume to enter the water. If you weigh, say, 150 lbs then you’re gonna need to push 150 lbs of water out of the way in the time it takes for you to enter the water, except that water is all surrounded by other water that you also need to push out of the way. It takes a lot of effort to push all that water any noticeable distance in the ~0.05 seconds it takes for your body to fully enter the water after jumping from the Golden Gate Bridge, that work is performed by your body decelerating at something like 20g (or more depending how you hit) to transfer energy from you to the water. This is a force that’s very difficult for a person to survive being exposed to.
Note: despite popular mythology the water tension is a trivial portion of this, or you’d be able to make the dive safely just by putting a few drops of washing detergent on the surface.
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Its the rapid deceleration that will kill you.
So, whether diving or jumping, if you present a small surface area on entry and therefore penetrate the surface and slow gradually you’ll be ok. Belly flop not ok. A feet-first vertical entry from a divable-height bridge jump would be ok.
Nobody has mentioned the diving pool bubbler systems yet. It’s basically an aerator at the bottom of the pool. It serves to reduce the density of the landing area as well as provide a visual for the diver.
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Much of its entry form. Even at survivable dive distances you can be severely injured if you don’t enter properly.
Just remember the difference when you were an idiot kid and did a belly flop of the public pool high dive compared to when you dove properly, now magnify that by 10 or more.
The main reason falling into water from a high location is so damaging is not the surface tension, but how quickly the submerged portion of your body slows down relative to your unsubmerged portion as you hit the water. It’s like hitting solid ground…but not. You basically crush yourself at the midpoint.
Bruh I ask this question all the time!! I’ve heard a lot of people don’t die on impact. Instead, they break a bunch of bones in their body from the height, preventing the ability to swim, and they end up drowning slowly and painfully.
Diving and falling on water are two **very** different things.
Have you ever fallen in the water with your back or your stomach? That hurts. Diving on the other hand – does not, because your hands break the tension.
Most of these answers are absurdly wrong.
Here’s the answer: a handful of highly trained people have done high dives a bit less than the height of the Golden Gate Bridge. That no one has successfully landed that height in competition indicates that thus far it’s not possible. But they’ve done close to it after being highly trained and landing in the exact right way to enable survival.
The divers off the bridge aren’t trained. And they’re not trying to survive, for the most part. And the conditions are completely different, such that it’s rarely survivable. There are many obstacles.
* The first one is surviving the fall. Falling from that height can inflict massive damage—ruptured internal organs, broken bones, concussion. The guy who has the unofficial record for a high dive, a highly trained individual, still dislocated his hip and had to be rescued. Has he done that off the bridge just randomly like other bridge divers, it’s not likely he’d have survived.
* The second is that there’s an involuntary reflex everyone has, NO MATTER HOW WELL TRAINED, [to inhale when suddenly immersed in very cold water](https://www.philacanoe.org/resources/Documents/cold%20water%20safety/Cold%20Water%20Gasp%20-%20Cold%20Shock%20Response%20.pdf). At the speed they’re going, this guarantees they’ll be inhaling when they’re submerged. This will lead to inhaling water, which in and of itself can lead to drowning. In any event that person will immediately be in great distress and underwater at that, with broken bones, ruptured organs, hypothermia, and probably a concussion. These record-setting dives are usually in warm water so the cold water reflex doesn’t apply.
* The third is that the water is extremely cold and will cause hypothermia quickly, making them lose strength, become confused, and be unable to continue
* the fourth is that their injuries, if not fatal, will prevent them from swimming to safety. The bay is brutally difficult to swim in. They have annual recreational swims in the bay—the Escape from Alcatraz Triathlons. They regularly have to rescue something like 10% of competitors, highly trained and motivated athletes who simply can’t handle the conditions. They’re wearing wetsuits to prevent hypothermia yet they still can’t manage. And their injuries will prevent them from having the strength to swim to safety—even if they’d been in good enough shape to have swam to safety in ideal conditions with no fall. No one ever successfully escaped Alcatraz. One dude got to a pylon but due to his hypothermia, still had to be rescued.
* fifth is the tide, which is powerful and will sweep you out to sea. The abovementioned triathlon contestants have to swim ESE in order to end up in San Francisco (the city is due south of Alcatraz) because the tide is pulling them so powerfully in a westward direction. It takes great strength and knowledge to swim the right way.
* sixth is that no one is looking around at the exact right moment to rescue them in most cases.
* eighth is that there’s a strong chance they’re unconscious from the fall and will drown as a result.
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