We had an incident this weekend where one of our cell phones broke. During a momentary change in the Earth's gravitational field, the phone came in untimely and forceful contact with a fireplace hearth. As a result, the screen of said phone cracked. Fortunately, and incredibly, we had another phone of the same type that had died of another cause earlier which still had a good screen. We were able to take the phone apart and swap the screen and all is good. Still it was a reminder of the dangers that our poor cell phones face every day. We were very lucky to be able to replace it.
You see these smart phones are substantially made of glass. Glass is very strong, but also quite brittle. They can withstand incredible impacts, but if they get a bonk a just the wrong angle - sproing - broken glass.
Of course, if you are PK Hunder and you are doing a totally rad ski jump for the X Games when your phone falls out of your pocket in mid air, you may be surprised to find it sliding down the icy hill behind you until it actually smacks into your ski boot at the bottom. PK was really lucky. Apparently his phone worked just fine after the episode. No cracks! See the video below.
On a related note, the number one cause of physical trauma to cell phones is water damage due to them being dropped in the toilet... so kids, remember, don't poop and text!