ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel
  • »
  • Education and Science»
  • Physics

Doppler’s Effect

Updated on July 2, 2015

Doppler’s Effect

When we are standing on the road, the intensity of an approaching car's horn increases. Likewise the intensity decreases as the car moves away.
When we are standing on the road, the intensity of an approaching car's horn increases. Likewise the intensity decreases as the car moves away.
The Doppler Effect: Stars moving toward us look bluer, stars moving away look redder.
The Doppler Effect: Stars moving toward us look bluer, stars moving away look redder.

The Doppler’s effect is the apparent change in frequency of sound, light or radio waves caused b the relative motion of the source, medium or observer. For example, when an approaching train blows its whistle, the pitch of the whistle seems higher as the train comes towards you. The pitch seems to lower when the train passes and goes away from you. The cause of this effect was first studied in 1842 by Christian Doppler, an Austrian physicist and today known as Doppler’s effect.

According to Doppler’s effect whenever sound source moves towards or away from the observer, the pitch of the sound as heard by the observer is slightly different than the one emitted by the source. When the source of sound is approaching each wave sent out by the source has a shorter distance to travel than the wave that was sent out earlier. Each wave reaches the listener a little sooner than it would have, if the source had not been moving. The waves seem to be more closely spaced. They have a higher frequency. As the source moves away each wave starts a little farther away. Each wave seems to be longer than it would ordinarily be. The pitch is lowered. When the source and observer are at rest or in motion in the same direction such that the speed of both is the same, the pitch of the sound does not change.

Doppler’s effect is true in case of light waves also but since the velocity of light is very large as compared to sound, it can not be detected by simple methods. Astronomers study the motion of stars and galaxies by measuring the apparent change in frequencies of light due to motion. It has been observed by the scientists that galaxies are moving away from us. This has been concluded on the basis of red shift and on the basis of the violet shift, we can find out if any star is coming towards us in this vast galaxy of stars.

The rotation of the sun can be measured with the help of Doppler’s effect. For this purpose the wavelength of light coming from the tow edges of the sun is measured.

The speed of fighter planes and submarines is measured by using Doppler’s effect in the battlefield and the Doppler’s effect also helps to determine the position of the fighter planes and submarines, particularly, during a war. An instrument called the laser Doppler velocity meter has been developed with the help of laser beams which is used basically to determine the velocity of fast moving objects.


    0 of 8192 characters used
    Post Comment

    • John MacNab profile image

      John MacNab 5 years ago from the banks of the St. Lawrence

      An interesting article, mdkshareef111. Thankk you for posting it on Hubpages.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: ""

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)