Publisher Summary Convection is a flow phenomenon that arises as a result of density differences in a fluid. In a solidifying casting, the density differences in the residual liquid can be the result of differences in solute content as a consequence of segregation. Convection can also arise as a result of density differences that result from temperature differences in the melt. Convection enhances the problems of uphill feeding in medium-section castings, making them extremely resistant to solution. In fact, increasing the amount of uphill feeding by increasing the diameter of the feeder neck, for instance, makes the feeding problem worse by increasing the opportunity for convection. If the solidification time of the casting is similar to the time taken for convection to become established, extensive remelting can be caused by convective flows. Serious damage to the micro and macrostructure of the casting can then occur.