THE ORIGIN OF LIFE IS ONE OF THE GREAT 

                           OUTSTANDING MYSTERIES OF SCIENCE.

The word "science" stems from the Latin "scientia" meaning "knowledge," and it's a root that makes perfect sense, as the practice heavily relies on the study of the natural world, be it physical, chemical, biological, or geological.

10 Science Principles See in Action Every Day

# 10

The Doppler Effect In Metrology:

When you hear an ambulance, police car, or other emergency vehicle in the distance, ever noticed how the pitch of the siren changes, first becoming higher as it approaches, then lower as it passes? What you're hearing is a result of a shift in the frequency of sound waves around the object, which is known more commonly as the Doppler Effect. It's named after Austrian mathematician and physicist Christian Doppler who first discovered this principle in the mid-1800s [source: National Oceanic and Atmospheric Association]. When something is moving toward you, sound waves bunch up, leading to an increase in pitch due to this compression. When it's moving away from you, the waves start to expand, leading to a decrease in sound.

The word "Doppler" may also bring to mind "Doppler radar," a term frequently thrown into the mix when it comes to meteorology.Most meteorologists rely on the Doppler radar system to provide accurate results on the distance and direction of rain. The Doppler Effect serves as a part of this process. The radar system uses a high-powered antenna to send out radio wave pulses. The amount needed for the pulses to bounce off the rain and return to the source is used to calculate the rain's distance and direction.

  Doppler Radar:

Police officers may not enjoy the comparison—given the public's general impression of bats as evil, blood-thirsty creatures—but in using radar as a basis to check for speeding violations, the police are applying a principle similar to that used by bats.The change in frequency experienced as a result of the Doppler effect is exactly twice the ratio between the velocity of the target (for instance, a speeding car) and the speed with which the radar pulse is directed toward the target. From this formula, it is possible to determine the velocity of the target when the frequency change and speed of radar propagation are known. The police officer's Doppler radar performs these calculations; then all the officer has to do is pull over the speeder and write a ticket.

Read more: http://www.scienceclarified.com/everyday/Real-Life-Physics-Vol-2/Doppler-Effect-Real-life-applications.html#ixzz3O8I0srcS
 

 The Doppler Effect In Astronomy:

The Doppler effect is of intense interest to astronomers who use the information about the shift in frequency of electromagnetic waves produced by moving stars in our galaxy and beyond in order to derive information about those stars and galaxies. The belief that the universe is expanding is based in part upon observations of electromagnetic waves emitted by stars in distant galaxies. Furthermore, specific information about stars within galaxies can be determined by application of the Doppler effect. Galaxies are clusters of stars that typically rotate about some center of mass point. Electromagnetic radiation emitted by such stars in a distant galaxy would appear to be shifted downward in frequency (a red shift) if the star is rotating in its cluster in a direction that is away from the Earth. On the other hand, there is an upward shift in frequency (a blue shift) of such observed radiation if the star is rotating in a direction that is towards the Earth.

Doppler Ultrasound Diagnoses:

Because Doppler is used to measure changes in sound waves, it is used to diagnose conditions related to circulation and blood flow. The Doppler ultrasound can actually measure how fast or slow blood is moving, which can indicate a circulatory problem. Blood clots can be found using Doppler ultrasound because the ultrasound will be able to detect slower blood flow or a lack of blood flow where the clot is located. Doppler ultrasound can also be used to identify narrowed arteries, plaque buildup in the blood vessels, or blocked arteries. Found early, many of these conditions can be treated before they become more serious.

Doppler Ultrasound Benefits:

The main benefit of Doppler ultrasound is that it is less invasive than other procedures used to identify these types of medical problems. The ultrasound is perform on the outside of the body and is not painful. Some discomfort may be experienced as the transducer is used, but it is often minimal. Because the ultrasound is not invasive, there are fewer risks to using it as a diagnostic test and many patients are able to have serious conditions detected without having to spend extensive time in the hospital.