Science of Doppler Effect in technology

TECHNOLOGY

By MICHAEL JOHN UGLO
FROM now onwards we do not have to take life as normal. It is not normal as you will discover in Doppler Effect working in technology.
For instance, when one person has an idea and starts working on it, you will see a change there. Now, that is not normal simply because prior to this such an exact thing had not been done by anyone in space and time. So you can see that everything we do and talk about every day is not normal.
The above implies that we have this huge potential to do something which we do not realise and do not always give serious thought to. We are trying to talk about the Doppler Effect seemingly as an ordinary event but it has huge a revolutionising effect as will be show in the following discussion.
Let me illustrate this idea with my own experience. I have realised that I have a potential which could turn ordinary things into wonders in technology. I decided to write a textbook for Physics, Biology and Chemistry in PNG but in order to bridge this idea, I realised that there is correspondingly an ocean need for a general Science textbook. So, on record in PNG I wrote that first science textbook in this country in the world of science and technology.
My textbook is entitled Science in PNG, Pacific, Asia and Caribbean. Interestingly, the textbook’s content is certified by Dr Augustine Munkaje (PhD) Biology Department of UPNG, Professor Topul Rali (PhD) head of Chemistry Department, UPNG, Julias Pano, Physics lecturer, Physics Department and Dr Espie Joseph (PhD) head of Geology Department of the University of Papua New Guinea.
Hence, it is endorsed as a textbook illustrating fundamental science (physics, chemistry, biology, geology) concepts to be used in PNG schools authoriszed from the office of the then Vice Chancellor Professor Ross Hynes (PhD). Furthermore, this book was highly recommended for use in PNG schools by Dr Eliakim Apelis (PhD) of National Department of Education, then Secretary late Dr Joseph Pagelio (PhD) and then Education Minister and current Prime Minister Honourable James Marape.
The book was published in first edition in the year 2008. The second edition is ready to come out very soon so the nation should grasp it. The reason being that if anyone wants to pursue a career in the field of science like engineering, medicine, aviation, geology etc, it starts from fundamental science for proper grounding. This is like learning the alphabet first before spelling words and writing sentences together with reading.
In Doppler Effect, we could correctly call it Doppler Shift as it is known inter- changeably. The reason being that any two events are taken into account. The first is the shift in the wavelength of an electromagnetic wave or a wave from a sound from a loud hailer or anyone’s voice as an acoustic wave. The second is a change in the phase of a wave that is a phase shift of a wave. We will see how these two phenomena come into play in the following discussions.
For non-scientists a wavelength is a case where when a message travels through the air or another medium like a solid such as a metal, water or wood, it comes in a straight line seemingly but when you take a microscope and magnify that line, you will see that it comes as a wave like the ripples you see on water bodies when you drop a small pebble onto it. You are generating those waves clearly on the water body known as longitudinal waves versus another wave called transverse waves. Transverse waves compose what we always infer as the electromagnetic waves. From one wave crest to the next wave crest gives you the size of the wave known as the wavelength.
Doppler effect happens when one car sounds its horn and a person is observing from a distance. Now the several incidences happen here: the car will be stationary, that is staying at the same spot and the observer is moving towards it or away from it. It can also happen that the car will sound its horn and approach the observer or the car will sound its horn and move away from the observer while the observer is stationary meaning the observer is at the same spot and not moving. The other thing that will happen is that, both the observer and the car with its horn sounding move towards each other, away from each other or in addition one following the other.
In the above instance we see that the sound is a travelling wave. This time the sound wave is travelling in the air. So, the point is, the observer will see constant wave crests between the observer and the car with its horn when both are stationary. The wave crests will be appearing closer to the observer with reduced wavelengths when either the car or the observer or both approach each other. Doppler Effect is very important in technology as it has many applications as we will further explore in this lecture.

Importance of Doppler Effect and technology
Doppler Effect is named after an Austrian physicist named Christian Doppler who recognised the effect and documented it in 1842. The Importance of the Doppler Effect is that the speed of any star or galactic body and activities can be calculated with high precision.
For instance, the use of the two associated terms such as the redshifts and the blueshifts do the jobs of the calculation as we have mentioned above. You can see we had ancient astronomers and meteorologist who actually used these characters. Illustrations are stories of the three kings from the East who studied the stars to bring the precious gifts for the little baby Jesus in Bethlehem. Some extraordinary movement in the Doppler Effect in the red and blue shifts happened that prompted those great ancient astronomers and now we can say astrophysicists have realised. To date, this is the obvious and technologically known method ancient astrophysics can use to study the stars and their associated dynamics.
When a star is moving towards the earth in thousands, millions or even billions of lightyears units, then you can see a blueshift wave crest’s spectrum because blue spectrum is high powered and has a reduced or shorter wavelength.
On the contrary, when you see a redshift spectrum, then you automatically know that the wave crest are further apart or departing from each other. Thus, it speaks of the wavelengths to be elongated or of a magnitude that is exceedingly sizable.
Knowing the above conditions are the initial parameters that can enable one to accurately calculate the magnitude of the Doppler Effect happening in space with partial differential equations.

Technology and application of Doppler Effect
In the application of Doppler Effect with technology, particularly the security systems and the police use this tool to apprehend offenders in traffic and anyone in an automobile. A radar system that uses radio waves to detect and apportions ranges is Doppler Effect at work when the search automobile is approaching or far-flung. A computer software can correctly calculate the distance for the searcher to close in.
Also, another application is in the medical field whereby the Doppler Effect or Doppler shift as a shift in the phase of a wave becomes paramount here as we referred earlier in the beginning of this lecture. That is to check and ascertain the blood flow of the left and right atria, ventricles and valves. It makes sure blood does not flow backwards as always taken care of by the valves of the heart. The very high sonar frequency of the device is used to send acoustic waves parallel to the flow of the blood which should flow in phase with the blood. Any lapse detected in the phase of the wave signal shows aberrations that needs to be examined and diagnosed for an antidote.
The Doppler Effect is also used in the moving vehicles to detect obstacles in surroundings of the latest technologically advanced vehicles like the driverless cars. The Doppler Effect employed always ensures that the vehicle is always maintaining its right pathway with the built-in cameras and computers that perfectly upholds this accuracy.
Arriving technologies in Doppler Effect
Future application in the Doppler Effect in technology is that your body gestures to a computing machine can be converted to waves that a computing device can recognise whether you are close enough to undertake the action or not. Websites are designed by the Microsoft team together with camera technology that help according to the Indy/Life newsletter.
Further to this is the driverless vehicles that are programmed to work by the Doppler Effect with all technologies built in as explained above.
Also, a lot of babies are saved with the use of Doppler Effect in its application in scans done on pregnant mothers. Further medical uses are studied for this user-friendly technology.
My prayer for PNG today is: “Some men are money-mad, go about richly clad, seeking the rainbow’s ends. I tell you God will surely ditch among the rich, who have no poor man friend.“
Next week: Astrophysics in technology

• Michael John Uglo is a lecturer in Avionics, Auto-Piloting and Aircraft Engineering and has the textbook “Science in PNG, Pacific, Asia & Caribbean. Send comments to: [email protected]