This article describes the construction of an inexpensive, robust, and simple hydrogen electrode, as well as the use of this electrode to measure "standard" potentials. In the experiment described here the students can measure the reduction potentials of metal-metal ion pairs directly, without using a secondary reference electrode. Measurements with this electrode normally deviate less than 0.03 V from the standard reduction potential given in tables. (Contains 3 figures and 1 note.)