An electroresistivity probe was used to determine point properties of an air-fluidized bed of conducting coke particles. Interruptions of current between the electrodes of the probe and a large wall electrode were analyzed with the aid of a hybrid computer to yield information on bubble properties （frequency, volume fraction, size and size distribution and rising velocity） as a function as a function of fluidization level, particle size and position within the bed. The results are generally in agreement with available theory and literature data.