The role of bubblesBubble is essential in many engineering applications, such as in aerated concrete and bubble pumps. This paper reports the mechanisms of bubbles coalescenceCoalescence in a static liquid columnStatic liquid column. The experimentExperiment was conducted in a 100 mm outer diameter acrylic tube filled with 12 kg/ms glycerine liquid. A plunger was used to create bubbles of various sizes. A camera was used to capture the sequence of imagesImage of bubbles rising in the column. From the analysis, coalescence of bubbles with Dratio = Dleading/Dtrailing = 0.8 and 0.4 created a visible wake, which indicates a sudden increase in its velocity. For a coalescenceCoalescenceof bubblesBubble with Dratio = 0.4, there is no evidence of wake formationWake formation. Although the effect of bubbles Dratio towards its coalescence mechanism is not yet conclusive, the findings presented in this paper are substantial towards the understanding of bubble coalescenceCoalescence phenomena.