The dimension of interaction dynamics, d(2)(int), is used to study the nonlinear interactions in a fluidized bed between the local bubble, "bulk" bed and particle dynamic components. The different timescales are obtained by a multi-resolution analysis based on the Hilbert-Huang Transform Method (HHTM). The state space analysis is used to study the time-space structure of the fluidized bed dynamics. A method for constructing Poincare projections based on the join probability matrix computation is provided. The Kolmogorov entropy, K, and the correlation dimension, D-2, are used to compute the invariant properties of the corresponding attractor. It is concluded that the local bubble dynamics has chaotic features and is responsible for the determinism found in pressure fluctuation signals. It has been found that, as expected, the bubble component is the driver of the gas-solid fluidized bed hydrodynamics. (C) 2007 Elsevier Ltd. All rights reserved.