Radiation shielding is a key concept in controlling radiative heat transfer; shield is an opaque surface magnetic wave interchange. In principle, the shield attains an equilibrium temperature closer to the fluid temperature than the surroundings. Because the probe can no longer “ see” the surroundings, with the radiation shield in place, the probe temperature is closer to the fluid temperature. Additional information on radiation error in temperature is closer to the fliuid temperature. Additional information on radiation error in temperature measurement may be found in Sparrow14. The following example serves to demonstrate radiation error and the effect of shielding.