The small ItemPhysic mod adds realism to Minecraft by modifying the behavior of discarded items. It affects both vanilla things and those added using mods.
When ItemPhysic is installed, items will no longer hover above the surface. They will lie horizontally and look as realistic as possible. Also now light objects will float in the water, and heavy ones will sink. The changes also affected interactions with lava, in which not everything will burn. For example, stone blocks and precious stones will not collapse.