The Power of Imagery
Warning: This answer is about the artistic reason(s) for the levitating glove, not scientific reasons.
If you're into such things, Man of Steel is rich with imagery and symbolism. Sometimes it's conspicuous, such as when Clark is at a church and the camera pauses ever so briefly with an anguished Clark in front of a crucified Christ. Sometimes it's a lot more subtle, such as when Jor-El's image is directing Clark and Lois on the ship, and it's all done with classical poses similar to those in Greco-Roman statues: This totally jibes with Kryptonian society in the movie being based heavily on Plato's "Republic." Another subtle one is the "baptism" of Clark when he goes through a trial by fire and ends up immersed in the ocean.
Anyways, as far as imagery goes, a gauntlet is a symbol of power. (side note: the difference between a glove and, more specifically, a gauntlet is, generally speaking, that a gauntlet is used in battle/war). Notice that it's not just the case that the viewer can see a gauntlet floating---it's actually the case that the glove is foregrounded in a shot, taking up almost the entire frame, and the camera ever so subtly pauses there for just a brief moment.
So I would suggest that scene may have been less about a scientific reason and more about an artistic and symbolic message. Zod has just expressed his view that, essentially, might-makes-right when it comes to protecting Krypton (says something about even his "cruelty" was to serve Krypton's greater good). The glove symbolizes his power philosophy.