Biot number

The Biot number is a dimensionless quantity used in heat transfer to compare how quickly heat is conducted within an object to how quickly it is transferred from its surface to the environment. A low Biot number indicates the object’s interior heats or cools slowly compared to its surface, meaning temperature differences within the object are minimal. Conversely, a high Biot number suggests that the surface exchanges heat more rapidly than heat moves inside, leading to more significant internal temperature differences. It helps engineers predict how uniformly an object will change temperature during heating or cooling processes.