# Science Fair

Topics: Sound, Wave, Frequency Pages: 3 (704 words) Published: October 24, 2012
The Doppler effect

Design Variables

Research Problem

In our experiment, we will be testing the validity of the Doppler effect. The Doppler effect states that a change in frequency of a wave will occur for an observer that moves relative to the wave. This is seen in our everyday life, for example, when the siren of a police car or fire truck passes you, you are experiencing the Doppler effect.

Key Variables

Independent Variable: Original position of moving object (sound maker and sound recorder) Dependent Variable: Change in Wave Frequency (pitch of the note) Object moves at varying speeds of 5 mph intervals from 10 to 30 mph.

Hypothesis

We will verify that the Doppler effect is valid. If the sound travels from point A to point C and passes the listener at point B, then the wave frequency will change by becoming higher and then lowering after passing point B.

Design

Materials

Our materials for this project include:
* Sound recorder on IPod Touch
* Isolated parking lot with limited outside noise interference * Piano App on Laptop to produce constant sound
* Speakers
* Meter stick
* Car

Method

1. Gather materials for experiment (Sound recorder on IPod Touch, Isolated parking lot with limited outside noise interference, Piano App on Laptop to produce constant sound, speakers, Meter stick, Car) 2. Explanation: For this experiment, sound will be emitted starting at position A and moved at a constant speed from position A to position B while still producing sound. E.g. A police car with its siren on, moving from position A to position B at a constant speed of 35 mph. The sound recorder on IPod Touch will be directly in the middle of position A and position B and will be used to record the sound change. This recording will be put into a program that will transcribe the sound into musical notes. a. The Doppler effect states that the wave length (note of the sound, e.g. A# or C) will become...