anbello262 :
This is really interesting.
I understand it's almost impossible to measure accurately, but I'm also interested in knwoing for sure how much extra shatter protection (if any) does a screen protector provide?
The entire goal of a case / screen protector for your phone is to sloowww dooowwwnn acceleration from impacts.
Let's give a terrible example just so you can get the idea.
If I encased my phone in bricks, and dropped it on the floor, what do you think is going to happen?
My phone is going to get crushed by bricks due to bricks not having any softness or give in them, they are rigid for all intensive purposes.
Any shocks that the bricks take are instantly transferred to my phone due to how rigid the bricks are.
So now you may be thinking ok perfect ill just encase my phone is the softest material known to man, soapstone,
That may not have immediately come to mind, but its really really soft.
The problem with that is its so soft it disintegrates upon impact with almost anything making it a one time use case, you're phone would be protected for that first drop though.
So the middle ground here is a hard outer shell that can actually take a hit and a soft inner lining that can dissipate any hard shocks turn them into quite literally good vibrations for the phone.
And also they make a device made to measure these forces ... an accelerometer - Thanks Mythbusters.
(They started using shockwatch labels when they didn't have to be precise with the measurement)
You want the acceleration to be low.
To quote a cliche .... It isn't the fall that kills your phone it's the sudden stop
High acceleration going from about 10 mph to 0 near instantly, assuming a 1 meter drop.
If you are just in the market for a screen protector you want to get one that uses soft clear plastic so that any impacts are minimized, but due to how thin most screen protectors are you can't expect a miracle, a case+screen protector is really the way to go.