Global Observables at RHIC

Main characteristics of the charged particle dN_ch/deta and transverse energy dE_T/deta production measured in Heavy Ion collisions at RHIC energies are presented in this article. Transformation of the pseudo-rapidity shape, relation to the incident energy and centrality profile are described in a systematic way. Centrality profile is shown to be closely bound to the number of nucleons participating in the collisions, at the same time an alternative approach to study the centrality behavior is also discussed.