Lightning Bolt

In OD&D and AD&D, the spell Lightning Bolt rebounds and doubles back if space limitations and/or a non-conducting barrier, such as stone wall, prevents it from extending to its full length. (Men & Magic 25; 1E PHB 74; 1E DMG 45). Non-conductive materials include most non-metallic minerals as well as glass and wood. So while the spell will "sunder wooden doors," "splinter up to 1' thickness of stone," and presumably shatter a window, it will rebound back from all of these surfaces "damage caused to interposing barriers notwithstanding." (1E PHB 74) By extension, a lightning bolt should not rebound when it strikes most bodies of water, because water is conductive unless it is pure, but apparently should not harm living creatures that are fully submerged. But what is the justification for the rebound from non-conductive surface? Is there an actual basis in physics for this phenomenon?