Abstract
The Doppler effect has many applications in science and engineering fields.
Although the format of the classical Doppler effect equation is simple, the
derivation for the equation in physics textbooks is not intuitive to many
students. This article provides a simple but effective model to illustrate the
derivation for the classical Doppler effect equation. This model visualizes
frequency, wavelength, and wave speed, which helps students to establish an
intuitive and clear understanding of mechanical waves. This model also provides
a clear visualization that the wave speed is unchanging in an underlying
medium, which is a key point to understand the classical Doppler effect.