# What is k in Newton's Law of Cooling?

T (t) = T_e + (T_0 − T_e )*e^ (- kt)
where T$\left(t\right)$ is the temperature of the object at time t, ${T}_{e}$ is the constant temperature of the environment,${T}_{0}$ is the initial temperature of the object, and $k$ is a constant that depends on the material properties of the object.
So, $k$ is a constant in relation to the same type of object. If we change the object and its material properties, the constant $k$ will have a different value (for instance, silver will have a different $k$ from wood).