Why are airplane windows round? | #aumsum #kids #science #education #children

When airplanes fly at higher altitudes, the air pressure inside the airplane is more than the air pressure outside. Hence, the cabin slightly expands, thus creating stress which flows through the cabin's material.

Now, when the windows were square or rectangular, the stress caused tension to build up at the corners of square windows. This tension produced cracks in the cabin, thus leading to crashes. Hence, this design flaw was corrected by making windows oval. Oval windows provide a smoother path for stress to flow due to which tension is not produced and hence, airplanes are safe.