Ever wondered why all planes' windows, whether on small or large planes, have round-shaped windows? Why are they not shaped like those in vehicles, in a square shape?
Interestingly, the reason is rooted in the aerodynamics of the plane. The rounded windows on today's planes are aimed at managing air pressure inside and outside the aircraft.
When cruising above 10,000 feet, aircraft cabins are pressurised against the atmospheric pressure on the outside.
This variance thus causes stress on the windows which, due to their shape, allows an even distribution of pressure across the panel.
Additionally, the design also withstands deformation better, making it stronger for long-term use.
The windows are made of three acrylic layers with the outermost being the thickest and taking all the pressure from the outside,
The middle layer is also thick and has a tiny hole used to equalise pressure and protect the inner pane.
The one passenger's face is the thinnest layer and only takes the relatively minor cabin pressure.
Notably, the idea to have planes have round windows came about in the 1950s when airlines began to fly their aircraft at higher altitudes.
Flying at high altitudes allowed them to save money thanks to the thinner air which creates less drag and a more comfortable ride with less turbulence.
However, at the time, airlines did not make the correct design changes to ensure passenger safety.
They used square windows, which created stress spots due to the pressure difference inside and outside the plane.
It is the use of square shapes that in 1954 led to a plane accident raising an urgent need for answers.
In the concerted effort to find answers, it was established that the square window design was the default and cause of the accident.
In particular, the edge of the square was picking up too much pressure, causing them to crack and destroy the aircraft.
The four sharp edges took up to 70% of the stress, causing them to fall apart.
Incidents of windows tearing open are extremely rare nowadays but windows remain an essential part of safety checks.
Equally, beyond looking good, rounded windows in particular keep passengers safer in the sky than windows with sharp edges would.
