Vernier Software & Technology

# Doppler Effect

## Introduction

No doubt you have experienced how the pitch of a car horn or siren changes as it approaches and then passes you. Because study of this effect with sound waves is difficult to visualize, one typically examines the Doppler effect with water waves in a ripple tank. Measurements of frequency and wavelength are easier to make, and changes in the waves due to the motion of the source are easier to observe. In this experiment, you will develop a causal model to account for the change in pitch and an expression relating the shifted frequency to the speed of the object and of the wave in the medium.

## Objectives

In this experiment, you will

• Use video analysis of the waves produced by a stationary source to determine the frequency, wavelength, and velocity of the waves in water.
• Perform similar analysis to determine the effect of a moving source on these quantities
• Determine the shifted frequency an observer would detect as the source approaches or recedes.
• Derive an expression relating the shifted frequency to the speed of the object and of the wave in the medium.

## Software for Experiment

This experiment uses Logger Pro software.

## Advanced Physics with Vernier — Beyond Mechanics

See other experiments from the lab book.

 1 Behavior of a Gas 2 Heat Engines 3 Standing Waves on a String 4 Standing Waves in a Column of Air 5 Doppler Effect 6 Electrostatics 7 Coulomb's Law 8 Mapping Electric Potential 9 Factors Affecting Electrical Resistance 10 Series and Parallel Circuits 11 Faraday’s Law: Moving Magnet 12 Faraday’s Law: Alternating Current 13 Capacitors and Inductors 14 RLC Circuits 15 Curved Mirrors and Images 16 Thin Lenses and Real Images 17 Thin Lenses and Virtual Images 18 Aperture and Depth of Field 19 Interference 20 Diffraction 21 Spectrum of Atomic Hydrogen 22 Planck’s Constant

### Experiment 5 from Advanced Physics with Vernier — Beyond Mechanics Lab Book

#### 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.