eli5: why did soldiers in pre ww1 wars have a “turn based” or organized battle?

Question

This is probably false to some extent because I get this perception mainly from movies and other media, but did soldiers in old wars line up in formations exposing themselves and take turns to fire? If so, why?

Edit: Ty for all the detailed responses guys! I had one more question- wouldn’t it make more sense for them to spread out or take cover while fighting?

In: 2518

Answer 1

I assume the turn dynamics formed automatically because re-loading took a sh1tload of time.

The formations were probably just left-over habits.