Question

How can you determine wind direction by wetting your finger and holding it up in the air?

Answer 1

Hint: The process behind determining the direction of wind depends on evaporation.
Evaporation is a change in the state of matter in the liquid form to the vapor/gaseous form.
It is a very simple process and depends on factors such as weather and humidity.

Complete answer:
Lick the wad of your pointer and point it upwards.

See which side of your finger feels the coolest. Whichever course the cool side of your finger is confronting (north, south, east, west), that is the heading the breeze is coming from.

The motivation behind why your finger feels cool has to do with the rapid dissipation of the dampness on your finger as the breeze air blows across it.

Our bodies heat (through convection) a slight layer of air only close to our skin. (This layer of warm air protects us from the encompassing cold.) But at whatever point the breeze blows across our uncovered skin, it diverts this glow from our bodies. The quicker the breeze blows, the quicker the warmth is diverted. Also, on account of your finger, which turns out to be wet with salivation, the breeze will bring down the temperature considerably more rapidly because moving air vanishes the dampness at a faster rate than still air would.

Note: Since utilizing your finger as a weathervane relies upon vanishing occurring, it doesn't fill in also causing you to gauge wind course on damp or moist days.

At the point when the climate is damp, it implies that the air is now loaded up with water fume, thus, it will divert the extra dampness from your finger all the more gradually; the slower the dampness from your finger dissipates, the less you'll have the option to feel the breeze's cooling sensation.