The Millikan Oil Drop Experiment: Measuring the Charge of an Electron

Introduction

The Millikan oil drop experiment is a classic physics experiment that was first performed by Robert Millikan in 1913. The experiment measures the charge of an electron by observing the motion of a small oil drop in an electric field. The experiment was a major breakthrough in physics, as it provided the first clear evidence that the charge of an electron is quantized.

The Experimental Setup

The Millikan oil drop experiment uses a simple apparatus consisting of two parallel metal plates separated by a small distance. A small oil drop is placed between the plates, and an electric field is applied across the plates. The electric field causes the oil drop to move, and the rate of motion is measured.

By measuring the rate of motion of the oil drop, Millikan was able to determine the charge of the oil drop. He found that the charge of the oil drop was always a multiple of a fundamental charge, which he called the "elementary charge." The elementary charge is the charge of a single electron.

The Results of the Experiment

Millikan's oil drop experiment provided the first clear evidence that the charge of an electron is quantized. This means that the charge of an electron can only take on certain discrete values. The elementary charge is the smallest possible charge that an electron can have.

The Millikan oil drop experiment was a major breakthrough in physics. It provided the first clear evidence that the charge of an electron is quantized, and it helped to establish the foundation of modern physics.

Conclusion

The Millikan oil drop experiment is a classic example of the power of scientific experimentation. By carefully observing the motion of a small oil drop, Millikan was able to make a major breakthrough in our understanding of the fundamental nature of matter.