In practice, thermoelectric effects are essentially unobservable for a localized hot or cold spot in a single homogeneous conducting material, since the overall emfs from the increasing and decreasing temperature gradients will perfectly cancel out. Attaching an electrode to the hotspot in an attempt to measure the locally shifted voltage will only partly succeed: it means another temperature gradient will appear inside of the electrode, and so the overall emf will depend on the difference in Seebeck coefficients between the electrode and the conductor it is attached to.