We propose a series of experiments involving balance readings of an object naturally floating or forced to be partially or fully immersed in water contained in a beaker sitting on an electronic scale balance. Students were asked to predict, observe and explain each case. The teacher facilitated the learning by asking probing questions, giving hints and helping in the drawing of the free body diagrams. From this guided enquiry, students improved their understanding of the involvement of Newton's third law in each experiment. (Contains 3 figures.)