A litter bag is a small bag of wire mesh or soft 'screen door' mesh used to study decomposition. 'Litter' such as leaves is put in this bag and left laying around or placed half-buried in rotting leaves. The dry weight of the leaves is taken before this happens, and you can periodically remove the litter bag and see how much of the leaf has been decomposed. The size of the holes in the bag can determine which small organisms are most important decomposers in an area. For instance, if you use thin mesh, earthworms cant get in and help with the decomposition.

Boring you say? perhaps so. In fact, that is what I was thinking in Soil Science class today. But the fact is 'litter bag' just sounds cool. It sounded like it needed a node. Plus, i think a litter bag would make a good projectile weapon.