Could You Survive a Falling Elevator? [w/ subs]



00:00:03 – So you’re in an elevator, just scrolling through your text messages as it zooms past
00:00:07 – the 15th floor.
00:00:08 – And then, suddenly, the elevator stops.
00:00:10 – That’s when you realize that you’re suspended in midair, and you’re /really/ high up.
00:00:15 – Maybe that’s when you start to wonder: could your elevator start plummeting to the ground
00:00:18 – any second now?
00:00:19 – And if it falls, could you survive it?
00:00:21 – The good news is that the elevator almost definitely won’t fall.
00:00:24 – There are lots of safety features designed to prevent a plunge, including multiple ropes
00:00:28 – and brakes.
00:00:29 – And if absolutely everything fails, then there are ways to minimize the damage by distributing
00:00:33 – the impact all across your body.
00:00:34 – But there’s no guarantee that you’d survive.
00:00:37 – In buildings with more than a few floors, the elevators are usually traction elevators.
00:00:41 – These work by attaching the car to metal ropes or belts and threading them through a motor,
00:00:45 – with counterweights on the other end of the cable.
00:00:46 – When the motor is active, it slowly threads cable through, moving the car up or down.
00:00:50 – If something goes wrong with the motor, the brakes stop the car.
00:00:53 – There are different kinds of brakes, but two common brakes are found in the motor and under
00:00:56 – the car.
00:00:57 – The brakes in the motor will make the cables jam and stop as soon as the power goes off.
00:01:01 – Meanwhile, the brakes under the car are usually designed to detect if the car’s moving too
00:01:04 – fast.
00:01:05 – If it is, the brakes release a metal wedge into the rails along the elevator shaft.
00:01:09 – The friction between the wedge and the rail is strong enough to slow the car down and
00:01:12 – eventually make it stop.
00:01:13 – So if the motor suddenly stopped working, the brakes would suddenly /start/ working.
00:01:16 – It’s incredibly unlikely that both the motor /and/ all the brakes would fail.
00:01:20 – But if they did, that’s when the counterweights would come into play.
00:01:22 – The counterweights are on the other side of the metal cable, and they’re normally about
00:01:26 – the weight of the elevator car when it’s half full.
00:01:28 – In the best case scenario, you’d have the right number of people in the elevator so
00:01:31 – that it exactly balances the counterweight — so if you’re really lucky, you might
00:01:34 – not move at all.
00:01:35 – And if you’re alone in the elevator, you might actually be lighter than the counterweights,
00:01:38 – and start moving upward — though that can still be dangerous if the car is moving too
00:01:42 – fast when it crashes into the top of the elevator shaft.
00:01:44 – If it’s a full car, you’ll probably be heavier than the counterweights, and start
00:01:47 – moving down.
00:01:48 – In either situation, the counterweights balance out some of the acceleration from gravity.
00:01:52 – By the time you reach the top or bottom of the elevator shaft, you won’t be moving
00:01:56 – as fast as you would otherwise.
00:01:57 – But a lot of the time you can still expect a pretty dangerous drop — especially if you’re
00:02:01 – a long way from the end of the elevator shaft.
00:02:03 – There’s also the possibility that the brakes fail /and/ the cables snap, but there are
00:02:07 – hardly any known cases of that happening.
00:02:08 – Most elevators have multiple cables, and every single cable is designed to be able to hold
00:02:12 – the weight of a full car.
00:02:14 – In fact, it’s pretty common for elevators to have up to /eight/ cables, and with a safety
00:02:18 – factor of 12 — meaning that all the cables together can hold a weight equivalent to 12
00:02:22 – times the weight of a fully-loaded car.
00:02:24 – So even if a cable /did/ break, you’d have others holding you up.
00:02:27 – There’s one famous case where an elevator’s brakes failed and its cables snapped — it
00:02:30 – happened in 1945, when a pilot accidentally crashed his plane into the Empire State Building.
00:02:36 – A woman named Betty Lou Oliver was told to get in an elevator to get out of the building.
00:02:40 – But the cables were weakened by fire, and they snapped.
00:02:43 – Oliver and the car fell over 75 stories to the basement.
00:02:48 – And … Oliver survived.
00:02:49 – It’s not clear exactly /how/ she survived, but one possibility is that the car was moving
00:02:53 – so fast that it compressed the air below to the point where it actually cushioned her
00:02:58 – fall.
00:02:59 – Another possible explanation is that all the broken cables piled up at the bottom of the
00:03:02 – shaft and softened the impact.
00:03:04 – Whatever happened, the elevator basically had a built-in safety net.
00:03:07 – But back to your stuck elevator on the 15th floor.
00:03:09 – You’re still worried that it might fall, even though you know that’s super unlikely.
00:03:13 – If it does, you might’ve heard that you’re more likely to survive if you jump just before
00:03:17 – you hit the ground.
00:03:18 – But there are two main problems with that idea.
00:03:20 – First, the timing has to be absolutely perfect, so that you’re jumping /exactly/ when the
00:03:24 – car hits the ground.
00:03:25 – And second, you’d need to have an exceptionally strong jump.
00:03:28 – Chances are you’re moving really, really, fast, and your jump won’t be powerful enough
00:03:32 – to make a difference in your speed when you hit the ground.
00:03:34 – So a more realistic option might be to lay your body against the floor.
00:03:38 – Even that can be tricky.
00:03:39 – If the ropes are broken and you’re in free fall, you’ll feel weightless and it’ll
00:03:42 – be hard to pull yourself to the floor.
00:03:44 – But if you manage to do that, then the impact will be distributed more evenly across your
00:03:48 – body.
00:03:49 – It’s not a guarantee you’ll survive, but it might be your best shot.
00:03:52 – Thanks for watching this episode of SciShow, which was brought to you by our patrons on
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