The aim of this paper is to investigate the stability of a bottle filled with different volumes of
water, and to determine the angle at which it topples over for each volume of water. Data for the
angle at which the bottle toppled were gathered experimentally using a cylindrical 1 litre bottle,
and two theoretical models were then developed, considering the fluid as both static and dynamic,
respectively. By modeling the water as a uniform cylinder or as a rectangular cylinder and
cylindrical segment, it was possible to calculate the angle at which the centre of mass of the
system overshot the base of the bottle. Allowing for some discrepancies between the geometry of the
actual bottle and that of the idealised model, it was found that both models could successfully
predict the variation of the toppling angle with volume. However, it was found that the second
model, which treated the fluid dynamically, was more appropriate, and better supported by the
empirical data gathered. The…