The chemical method of separating two compounds depends on their difference in solubility in water, ether, dilute acid or alkali. Separatory funnel thus, are used to distinguish immiscible fluids from their solutes. The funnel is usually made of glass, pear-shaped, and usually contains a stopper and a stopcock.
The movement of air is a convection current. Convection currents occur when warm air rises, cools down, and sinks due to gained density, replacing the warm air closer to the ground, creating a cycle.