why a flame of fire faces to the upward direction and not to the downward direction even having the effect of gravity?

The upward direction of a flame, despite the force of gravity, is due to a combination of factors including heat, buoyancy, and air flow.

When a fire burns, it releases energy in the form of heat. This heat causes the nearby air to become hot and rise. As the hot air rises, it creates a flow of air known as convection currents. These convection currents are responsible for carrying the flame upwards.

Additionally, flames are buoyant, which means they are lighter than the surrounding air. This buoyancy helps the flame rise against the force of gravity.

To visualize this, imagine a hot air balloon. The flame at the bottom of the balloon provides the heat that causes the air inside to expand and become less dense than the surrounding air. As a result, the balloon, including the flame, rises upwards.

The combination of heat-induced convection currents and the buoyancy of the flame creates an upward flow of air that carries the flame in the same direction, against the pull of gravity.

It is worth noting that in specific situations where air flow or external factors influence the flame, it might not always point directly upwards. But in a relatively stable environment, such as a candle flame or a controlled fire, the upward direction is the most common due to the factors mentioned above.