The most common cause of stratification is variation in the transporting ability of the depositing agent. Water and wind sort sediments according to size, weight, and shape of particles, and these sediments settle in layers of relative homogeneity.

Consistent with its micro orientation, symbolic interactionism tries to understand stratification by looking at people’s interaction and understandings in their daily lives. Rather, it examines the differences that stratification makes for people’s lifestyles and their interaction with other people.

Social stratification causes social disparity and many problems as it is an unjust system with monopoly of power and wealth in a particular group. It creates emotional stress and depression for the people belonging to lower social stratum as they have unequal access to wealth, power and prestige.

Lake number, LN, is the ratio of the strength of stratification to the effect of the wind stress. LN < <1 means stratification is weak with respect to wind stress, and the lake will mix. LN >>1 means stratification is strong and dominates the forces introduced by surface wind energy.

Unstable conditions exist when density decreases with depth. Mixing due to cooling or warming processes that increase the density of surface waters sufficiently to cause them to sink results in what is termed circulation, or overturn, of lake waters.

Lake turnover is the process of a lake’s water turning over from top (epilimnion) to bottom (hypolimnion). During the fall, the warm surface water begins to cool. As water cools, it becomes more dense, causing it to sink. This dense water forces the water of the hypolimnion to rise, “turning over” the layers.

Lake turnover is extremely important in freshwater lakes, as it is the event that is responsible for replenishing dissolved oxygen levels in the deepest lake waters. When the lakes are a uniform temperature and density, it takes relatively little wind energy to mix water deep into the lake.