The dynamic model	

The dynamic model includes two types of interaction diagrams: 
the sequence diagram and the collaboration diagram. Both 
diagrams illustrate how objects talk to one another. The interaction 
diagrams describe the communication between the participating 
objects and thus provide valuable information about the attributes 
and interfaces of the participating domain objects. When the 
object model is partitioned, the associations between objects 
must be preserved because they translate into dependencies 
between partitions.