system
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human
[Star Trek] how do shields work exactly?

So I was watching Star Trek Into Darkness last night, got to one of the scenes where the Vengeance just lights up the enterprise with its lasers. Big chunks are blown off the ship, people die, the whole shebang. Then I think sulu says shields are down to 5%. If the shields were up how come the ship took damage?
gpt
The ships still have armor. Shields can be used in ways besides just "Stop projectile" 

Those scenes where the hull was being shredded and chunk blown off look bad, and they are, but without the shields sealing off breaches or holding the hull together the ship would have been destroyed in the first salvo. 

More advanced shields like from TNG can soak much more damage and deflect that damage out to space but the OG timeline had shields that werent nearly as tanky. 

Imagine a submarine with a field that can maintain hull integrity(Literally hold it together), soak some damage and auto seal breaches.