Georg Ohm studied the resistances of different materials by conducting a series of meticulous experiments using simple electrical circuits. Here's how he did it:

1. Creating a Circuit: Ohm constructed a simple circuit consisting of a battery, a wire, and a device to measure the current (a galvanometer). He varied the length and thickness of the wire, as well as the type of material used.

2. Measuring Current and Voltage: He meticulously measured the current flowing through the wire using the galvanometer and the voltage across the wire using a separate device.

3. Analyzing the Data: Ohm noticed a consistent relationship between the current flowing through the wire and the voltage applied across it. He observed that the current was directly proportional to the voltage, and this proportionality was influenced by the material, length, and cross-sectional area of the wire.

4. Formulating Ohm's Law: Based on his experiments, Ohm formulated the famous Ohm's Law, which states that the current flowing through a conductor is directly proportional to the voltage applied across its ends, provided that the temperature and other physical conditions remain constant. This relationship can be expressed as:

I = V/R

Where:

* I = Current (measured in Amperes)

* V = Voltage (measured in Volts)

* R = Resistance (measured in Ohms)

5. Determining Resistance: Ohm's law allows us to calculate the resistance of a material by rearranging the equation:

R = V/I

This means that by measuring the voltage across the wire and the current flowing through it, Ohm could determine the resistance of the wire.

Ohm's experiments and the subsequent formulation of Ohm's Law provided a fundamental understanding of how materials conduct electricity and the concept of electrical resistance. This knowledge is crucial in the design and analysis of electrical circuits and devices.