Champagne bubbles, like bubbles in any liquid, do not rise in a straight trajectory. They follow a helical (corkscrew) trajectory when they ascend through a liquid. The trajectory of a bubble in a liquid is influenced by several factors, including the density of the liquid, the size and shape of the bubble, and the surface tension of the liquid.

In the case of champagne, the bubbles are formed due to the release of carbon dioxide gas when the bottle is opened. These bubbles are initially very small but gradually coalesce and grow in size as they rise. As the bubbles rise, they experience a buoyancy force due to the difference in density between the gas inside the bubbles and the liquid champagne. This buoyancy force pushes the bubbles upward.

However, the bubbles also experience a frictional drag force due to the interaction of the bubble surface with the surrounding liquid. This drag force opposes the upward movement of the bubbles. The combination of the buoyancy force and the drag force causes the bubbles to follow a helical trajectory as they rise.

Furthermore, the presence of residual impurities and dissolved solids in the champagne can also contribute to the deviation of the bubbles' motion from a straight trajectory. These impurities can act as nucleation sites for bubble formation, influencing the overall shape and path of the bubbles as they ascend through the liquid.