Why Airplane Windows are Round
“Why are airplane windows round?”
The low-pressure environment that airplanes fly at means that not only must they use a special glass but also a special shape. Because the internal pressure of the cabin is much higher than the external environment, the airplane will expand, inducing stress in the exterior. If square windows are used, then this stress will become overly concentrated and may break the plane. As a result, ovular windows must be used to ensure a smooth distribution of stress. This is Why Airplane Windows are Round.