The recent plane crash of an Alaska Airlines Boeing sparked two prominent questions among the public. The first was concerned with how the plane missed a door, while the second was focused on the miraculous survival of a smartphone at a height of approximately five thousand metres.
Among the wreckage which included a tailgate found in a Portland resident’s garden, ‘scrap hunters’ who were alerted by the authorities also discovered an iPhone. This phone had been forcefully dislodged from the owner’s grip when the cabin depressurized. Astonishingly, the iPhone was virtually untouched, even displaying a receipt for excess baggage payment on its undamaged screen.
This occurrence could be seen as a huge advertisement for Apple since the phone was an iPhone. However, experts consulted by USA Today and the Washington Post explained that the smartphone’s survival was not due to its manufacturer, Apple. Rather, the survival was a matter of physics, not the physical attributes of the phone.
David Rakestraw, a scientist at the Lawrence Livermore National Laboratory in California and an expert in drop tests, explained three factors that contributed to the phone’s survival. Firstly, phone manufacturers have made efforts to increase their products’ resistance, considering the frequency at which phones are dropped. Secondly, phone cases and screen protectors also played a role in protecting the phone. Lastly, the location of the phone’s landing could also have contributed to its survival.
The phone was discovered under a bush beside a road. According to Rakestraw, when an object is dropped, it carries momentum which is a product of mass and velocity. The outcome is determined by when and what stops the object. This can be compared to the difference between hitting a brick wall and falling onto a pillow. The pillow, similar to airbags in cars and SAFER barriers on race tracks, absorbs the force and reduces the impact over a longer duration. This is just like the phone cases which are made from a material that flexes, or “creaks a little”.
The phone that was dislodged from the plane would have reached terminal velocity at the onset of its fall, explained Lou Bloomfield, a retired physics professor at the University of Virginia. This means that the phone’s downward speed increased until the upward force of air resistance, or drag, equaled the downward force of gravity. Hence, the phone stopped accelerating downward and maintained a constant speed.
According to Bloomfield, the phone’s fall speed was not excessively high, probably around 100 miles per hour or even less. It was slow enough to withstand an impact with soft grass. A crucial factor would have been the phone’s resistance point. If the phone had fallen a few feet sideways and hit the road instead of bushes, the outcome would have been different. There is a possibility that the phone bounced off branches which further absorbed the impact before it hit the ground, added Rakestraw.
Though smartphone screens have become more durable over time, this phone’s survival was likely due to physics, primarily air resistance, affirmed Duncan Watts, a researcher at the Institute for Theoretical Astrophysics at the University of Oslo. An object falling towards Earth will reach a point, known as terminal velocity, where gravity can no longer accelerate it due to air resistance. Watts pointed out that a phone falling from a pocket hits the ground at about 10 miles per hour, while one falling from a plane probably only reaches 50 miles per hour. The grass or foliage that it landed on also contributed to its survival.
