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This is known as the Doppler effect. As the train approaches you, the wavelength of the sound waves it emits are compressed, and therefore the whistle sounds higher. When the train is moving away, the wavelengths are extended, causing the whistle to sound lower. If the train were not moving at all, the pitch you would hear from the whistle would be somewhere between the high and low pitches you hear when the train is moving.
This is known as the Doppler effect. As the train approaches you, the wavelength of the sound waves it emits are compressed, and therefore the whistle sounds higher. When the train is moving away, the wavelengths are extended, causing the whistle to sound lower. If the train were not moving at all, the pitch you would hear from the whistle would be somewhere between the high and low pitches you hear when the train is moving.
This is known as the Doppler effect. As the train approaches you, the wavelength of the sound waves it emits are compressed, and therefore the whistle sounds higher. When the train is moving away, the wavelengths are extended, causing the whistle to sound lower. If the train were not moving at all, the pitch you would hear from the whistle would be somewhere between the high and low pitches you hear when the train is moving.
This is known as the Doppler effect. As the train approaches you, the wavelength of the sound waves it emits are compressed, and therefore the whistle sounds higher. When the train is moving away, the wavelengths are extended, causing the whistle to sound lower. If the train were not moving at all, the pitch you would hear from the whistle would be somewhere between the high and low pitches you hear when the train is moving.Read more: http://wiki.answers.com/Why_is_the_pitch_of_a_train's_whistle_higher_as_the_train_approaches_and_loweras_it_moves_away#ixzz1DToTuS3j
sound is wavelengths, and wavelengths get compressed when coming to you (and stretched when going away). the closer the wavelengths, the higher the pitch!
As loud as a train whistle from 10 ft away.
Hold a treat and if he/she looks away whistle and wave the treat in front of their face.
It is the effect that happens when waves like sound are moving in relation to another object. In the classic train whistle example, The whistle suddenly drops in pitch as it passes you and starts to move away from you. This is because the sound waves now are stretched out, giving them a lower pitch. It is useful. Doppler radar used in weather forecasting is one example.
the pitch doesnt actually change but it might sound quieter to you because the sound it being blown away
The Doppler radar used in weather forecasting measures the direction and speed, or velocity, of objects such as drops of precipitation. This is called the Doppler Effect and is used to determine whether movement in the atmosphere is horizontally toward or away from the radar, which aides in weather forecasting. The radar was named for J. Christian Doppler, an Austrian physicist, who was the first to articulate the reason an approaching train's whistle will sound higher than the whistle as the train moves away.
It is called the Doppler effect
About 30 minutes.