There has been conducted Physics research on a material, that is, monitoring electric characteristic of a material using four-point probe method. This research measures current and voltage. The result is used to determine resistivity of a material. The research uses 2 samples, that is, chalk and charcoal. The result shows the resistivity of the sample in the form of bulk (t>s) for chalk has high resistivity on voltage of 6.6 Volt. Meanwhile, resistivity on thick sheet (t<s) has high resistivity on voltage of 7 Volt. On the charcoal material, large resistivity (t>s) is in 6 Volt, and on large resistivity (t<s) is in 6.6 Volt.