  A review of the main results of detailed flow analysis in highly central and
semi-central heavy ion collisions at SIS energies is presented in the first
part of this paper. The influence of the mass of the colliding nuclei and
centrality on the collective expansion and the information on the equation of
state of compressed and hot baryonic matter is discussed. The second part is
dedicated to a similar type of analysis, based on the behaviour of the average
transverse momentum as a function of mass of different hadrons, at the other
extreme of energy range, where free baryonic fireballs are produced.
Information on the partonic and hadronic expansion, temperature and degree of
thermal equilibrium in p+p and Au+Au central collisions at 200 A.GeV is
presented.
