The deceptively cute Gray Jay is one of the most intrepid birds in North America, living in northern forests year-round and rearing chicks in the dark of winter. Highly curious and always on the lookout for food, Gray Jays eat just about anything, from berries to small animals. They may even land on your hand to grab a raisin or peanut.
A thermal insulator is something that prevents heat from moving from one place to another. There are 3 main ways that heat can travel: convection, conduction, and radiation. Typically the phrase 'thermal insulator' refers to a material that blocks conduction.
In physics, thermal conductivity (often denoted k, Î», or Îº) is the property of a material to conduct heat. It is evaluated primarily in terms of Fourier's Law for heat conduction. Heat transfer occurs at a lower rate across materials of low thermal conductivity than across materials of high thermal conductivity. Correspondingly, materials of high thermal conductivity are widely used in heat sink applications and materials of low thermal conductivity are used as thermal insulation. The thermal conductivity of a material may depend on temperature. The reciprocal of thermal conductivity is called thermal resistivity.