How do airplane windows keep out the cold?

The windows used in airplanes are made up of multiple layers of different materials, each serving a specific purpose in maintaining a comfortable cabin environment. Here are some key aspects that contribute to how airplane windows keep out the cold:

1. Layered Structure:

Airplane windows are not single panes, but rather consist of multiple layers with air gaps in between. This layered structure creates pockets of insulating air that act as a barrier against the cold external temperatures.

2. Acrylic/Glass Outer Layer:

The outermost layer of the window is usually made of a scratch-resistant acrylic or, in some cases, glass. Acrylic is lightweight and offers excellent resistance to weathering and temperature changes.

3. Heat-Reflecting Coating:

A thin metallic coating, often made of aluminum or silver, is applied to the inside surface of the outer window layer. This reflective coating helps to bounce back heat from inside the cabin, preventing it from escaping through the windows.

4. Insulating Layers:

Between the outer layer and the inner layer of the window, there are one or more layers of transparent insulating materials. These layers could be made of polycarbonate or acrylic with small air pockets, creating an additional barrier to heat transfer.

5. Pressurized Cabin:

Airplane cabins are pressurized to maintain comfortable air pressure levels for passengers. This pressurization helps to keep warm air inside the cabin and prevents cold outside air from seeping in through any gaps or openings.

6. Window Seals:

The windows are securely sealed within the fuselage to minimize air leakage around the edges. Seals made of rubber or silicone are used to ensure that the windows remain tightly shut, preventing drafts and heat loss.

7. Heating Systems:

Modern aircraft are equipped with heating systems that circulate warm air throughout the cabin. These systems ensure that a comfortable temperature is maintained despite the low external temperatures encountered at high altitudes.

By incorporating these design elements and materials, airplane windows are designed to keep the cabin warm and comfortable, even in extreme cold conditions. This enables passengers to enjoy their flights without having to endure discomfort from excessive cold.