What happens to the temperature of air at point 4 in a convection current diagram?

In a convection current diagram, the behavior of air at a specific point, such as point 4, is influenced by the dynamics of heat transfer and fluid movement. When considering the nature of convection, heated air becomes less dense and thus rises. At point 4, if we follow the principle of convection, which involves the movement of warm air rising and cool air sinking, it can be understood that the air is likely in a heated state, contributing to the upward transfer.

As warm air at the bottom heats and rises, it creates a cycle where the cooler air is drawn in to take its place. Therefore, at point 4, the upward movement signifies that the temperature of the air is increasing as it ascends, consistent with the behaviors of convection currents. The rising air would transfer not just temperature but also energy, reinforcing why the correct answer describes this upward movement accurately. Understanding this mechanism is crucial in grasping the foundational concepts of convection and thermodynamics in fluid mechanics.