The+Doppler+Effect

=Doppler Effect Applet = The doppler effect was named after Austrian physicist Christian Doppler who proposed it in 1842. In our simulation, a bug is creating a sound which moves through the air as a series of waves. When the waves pass our microphone, the sound is detected. The distance between any two waves is called the wavelength and the time interval between waves passing is called the period. The brain associates a certain musical pitch with each frequency; the higher the frequency, the higher the pitch. Likewise, shorter wavelengths produce higher pitches since more waves pass through a point every second. The sound that our microphone detects will change in pitch as the object passes. This change in pitch is called a ** __doppler effect__. Therefore, the definition of the doppler effect is that it is a change in the frequency with which waves from a given source reach an observer when the source and the observer are in rapid motion with respect to each other so that the fequency increases or decreases according to the speed at which the distance is decreasing or increasing. ** While the speed of sound does not change, the speed of the source of the sound is arbitrary. You can change the speed of the bug by using the slider at the bottom. Notice the sound waves the bug makes when it is really fast. You can look at the bar at the right side of the applet which shows the sound/frequency of the sound waves made by the bug. When the bug is moving slowly it is moving slower than the speed of sound therefore the waves it creates when in the direction it is moving has a higher frequency than the wave the bug is creating behind it(the bug is moving forward). When the bug is going faster than the speed of sound, you can see that the bug is not making any waves in front of it. The waves created at the back which are supposed to be in the front have a very high frequency and the waves after that have a low frequency. When the waves which have all gathered at the back of the bug get to the mic, notice that the frequency/sound gets the highest, and that doesn't stay very long. The waves at the back, after the high sound has finished has a low frequency/ sound. Click the //" Start " button to see the bug fly by the microphone without stopping. You can also use the // “ //Stop// ” button to see what happens at a specific moment. For example, you can click the //“ Stop ” button to when the bug is right over the mic to see the change in frequency. You can also use the // //“ <span style="color: #000000; font-family: 'Comic Sans MS',cursive;">Step Forward <span style="color: #000000; font-family: 'Comic Sans MS',cursive; font-style: normal;">” and ////<span style="color: #000000; font-family: 'Comic Sans MS',cursive; font-style: normal;">“ <span style="color: #000000; font-family: 'Comic Sans MS',cursive;">Step Back <span style="color: #000000; font-family: 'Comic Sans MS',cursive; font-style: normal;">” to see what happens in a specific moment too. For example, when the bug is moving faster than the speed of sound, you can stop, step back and forward to see when the frequency changes. The numbers at the bottom of the applet don't change, you dont need to worry about them. // <span style="display: block; font-family: 'Comic Sans MS',cursive; font-weight: normal; text-align: left;">[](you can also download the applet for future reference, for doing that, click "Download Applet") <span style="display: block; font-family: 'Comic Sans MS',cursive; text-align: left;"> This applet is created by NASA researchers. NASA is very famous, and is known for researching about Space and Science. This website will take you to the main page of the nasa website. It has useful information for public, students and for employees. This site was made for students( students of colleges) to understand the doppler effect. <span style="display: block; font-family: 'Comic Sans MS',cursive; font-weight: normal; text-align: left;">[] <span style="display: block; font-family: 'Comic Sans MS',cursive; text-align: left;">

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