Polar easterlies are the cold and dry wind that blows from the polar regions (North pole and South pole) to the region of 60 degrees latitude. This type of wind is formed due to the sinking of the cold air resulting in the formation of a high pressure zone at both the poles. This wind when blows from the poles to the 60 degrees latitude, it slightly gets deviated towards the western side because of the effect of the Coriolis force. This Coriolis force comes into the picture due to the earth's continuous rotation.
Thus, the polar easterlies determines how far south the cold air travels from the North Pole.
Scientific investigations that involve some kind of testing will make use of observations. generally speaking making observations is the first step of the scientific method.
