# Elastic and Inelastic Mass

I'm studying collisions in terms of basic mechanics (impulse, rebound, momentum, etc.)

I'm curious about the structure of types of mass that have elasticity and others than have less. I'm interested in why the masses behave they way they do because of their structure. Would somewhere here who knows even just a little about mass structure difference give a brief description of elastic type and inelastic type structures? (I mean elastic and inelastic mass in terms of how they behave toward each other in collisions.)