Vernier Software and Technology
Vernier Software & Technology

Doppler Effect: Sound Waves


Have you ever noticed that if a car with a horn blowing is moving past you rapidly that the sound waves emitted by the horn seems to change frequency? In 1842 an Austrian physicist, Hans Christian Doppler, observed and analyzed the same phenomenon for sound emitted by a passing train. Hence the phenomenon is known as the Doppler Effect.

A similar effect is found for the propagation of light and other electromagnetic waves from moving sources. In fact highway patrol officers use radar to measure Doppler shifts in radio waves so they can determine how fast vehicles are moving.

In this activity, you will work with movies of a honking car moving fairly rapidly on a straight level road past a stationary microphone.


In this activity, you will

  • Verify that the Doppler Equations can be used to predict the ratio (fF / fB) of the apparent car horn frequencies before and after the car passes the microphone.

Software for Experiment

This experiment uses Logger Pro software for video analysis. The video for analysis is included with the lab book.

Physics with Video Analysis

See other experiments from the lab book.

1Rolling Ball
2Big and Small: How to Scale an Image
3Velocity Change
4Velocity and Speed
5Velocity and Acceleration
6Three Movies: Determining Constant Acceleration
7Demon Drop: A Mathematical Modeling Activity
8Jumping on the Moon
92D Vectors: Pool Ball Displacement, Velocity, and Speed
10Galileo's Projectile I: Using 17th Century Techniques
11Galileo's Projectile II: Using Contemporary Techniques
12Projectile Motion Vectors
13Frictional Slowing
14Impulsive Juggling
15Center of Mass Motions
16Finding a Spring Constant
17Net Work - Kinetic Energy Theorem
19Slinky Wave Speeds
20Superposition of Slinky Waves
21A Wave Pulse Equation
22Doppler Effect: Surface Water Waves
23Doppler Effect: Sound Waves
24A Heat Engine: Relating Work to the P-V Cycle
25Coulomb's Law for Two Charged Spheres
26Discharge Rate
27Electric Field Due to a Line of Charge
28Resistance and Ohm's Law
29Parallel Plate Capacitor: Potential Difference vs. Spacing
30Wiring Capacitors in Series and Parallel
31Using RC Decay to Determine Capacitance
32Exploring Faraday's Law
33Snell's Law of Refraction

Experiment 23 from Physics with Video Analysis Lab Book

<em>Physics with Video Analysis</em> book cover

Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.

Buy the Book

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