Blankets help keep you warm by providing insulation. They create a barrier between your body and the surrounding environment, reducing heat loss and trapping the warmth generated by your body.
When your body is at a higher temperature than its surroundings, it naturally radiates heat. This heat loss occurs through a process called thermal radiation, where your body emits infrared radiation. When you're in a cooler environment, such as a room with lower temperature, the heat will flow from your body to the surroundings.
A blanket acts as a thermal insulator by limiting the heat transfer between your body and the environment. It does so through several mechanisms:
Trapping body heat: Your body constantly generates heat as a byproduct of its metabolic processes. A blanket helps trap this heat close to your body, preventing it from dissipating into the surrounding air. The air pockets within the blanket's fibers or between the layers of the blanket create a stagnant layer of warm air, providing a buffer against the cooler air outside.
Reducing convection: Convection is the transfer of heat through the movement of air or fluids. When you're uncovered, the air in contact with your body warms up and rises, while cooler air moves in to replace it. This continuous circulation of air leads to heat loss. By covering yourself with a blanket, you create a barrier that slows down convection, reducing the heat loss caused by air movement.
Minimizing conduction: Conduction is the transfer of heat through direct contact between objects of different temperatures. When you lie on a cool surface, such as a mattress or a sofa, heat can be conducted away from your body. A blanket provides an additional layer of insulation between your body and the surface, reducing heat transfer through conduction.
Blocking radiation: Blankets can also reflect some of the radiant heat emitted by your body back towards you. The material of the blanket, especially if it has reflective properties, can bounce back a portion of the infrared radiation emitted by your body, helping to maintain your warmth.
By combining these insulation properties, blankets help to create a microclimate around your body, preserving your body heat and keeping you warm and comfortable even in cooler environments.