We all know how hectic road traffic is, and the worst part is driving in a traffic jam where we constantly have to change or alter the speed following the change of vehicle speed just in front of us. The accordion effect can be understood while studying about road traffic. In road traffic, there are typical decelerations and accelerations of the vehicle’s speed when the vehicle in front of it decelerates and accelerates.

If we study this in terms of Physics, then the Accordion effect has many names such as the Slinky effect, Concertina effect, Elastic band effect, and String instability effect. This effect occurs when the fluctuations in the motion of any traveling body cause disturbances in the flow of elements following it or just after it. This is what usually happens in road traffic, or even during bicycle or motor racing. This phenomenon can even be noticed in the Pipeline system. The accordion effect generally decreases the efficiency of the system in which it occurs.

In just the same way as the Wave effect, the Accordion effect also has all the particles move identically and follow each other’s path without deviating. Considering the example of road traffic, if there is a change in the motion of one vehicle, there is automatically a hanged adjustment in the vehicles following it. The change in motion can be positive or negative; positive means the speed increases slowly in a discontinuous fashion and negative means the speed keeps on decreasing in a discontinuous fashion.


In Physics, each wave travels in a specific direction along with a specific frequency while traveling in the atmosphere or any other medium. During this phenomenon, the wave particles usually experience some kind of hindrance in their path. These obstructions tend to change the velocity or frequency of the wave. This is not as simple as we think; a wave consists of numerous particles and all of them travel together in a bounded form and a specified path one after the other just as the students walk in a line going to the class. In this course, if any particle is obstructed or its path is hindered by any external force or any external object, the velocity of the particle changes and this, in turn, tends to change the velocity of the other particles that are just behind the one that has felt some kind of obstruction. The change in the velocity is not uniform. This does not mean that it is not at all uniform in any case, the change might be uniform as well as non-uniform depending on the nature of the wave, velocity of the wave, nature of the obstruction and the frequency with which obstruction has tried to stop the particle.


The best referential example is of the Road traffic, where all the vehicles move in a line and in a specific order where the change in one tends to change the other vehicle’s nature as well.  While traveling, some of the particles may deviate from the path even though they have been obstructed or not. Some particles stay in their path while some other washout here and there. This is also one of the factors that affect and cause the discontinuity of the path.

Here, we can say that a different phenomenon of Physics acting in one phase of this effect, the phenomena say that whenever a particle is traveling with some speed and velocity and it encounters an object in its path, then it transfers half of its energy or some of its energy to the object to which it is hindered by. But here this phenomenon has less relevance because here we consider the object to be stopped by the things on its path and not completely collapse with the other things on its path. The stopped particle is not assumed to transfer its energy to the object right in front of it, but the particle is assumed to be accelerated or retarded due to the factor of collision.


The Accordion effect can be most frequently seen in a traffic jam on the road but can also be seen when lots of people are standing in a queue. In this case, when many people are standing in a queue waiting for their turn to come up, as soon as the one in the first place does the work and leaves the queue, the queue moves one step forward. Here if any person comes and joins the line in between then the forward motion or moving one step forward of the queue is retarded.

Even when you are riding a bicycle, your pedaling speed increases the speed of the bicycle and you move forward. In case if you come across an animal or any object or any human on the road, then you immediately put your brakes on and try to stop your accelerated motion. In this way, the motion keeps on accelerating as well as it keeps on retarding but not in any particular manner. These are among the very few examples to explain the accordion effect. In conclusion, the accordion effect explains mainly what wave-particle experiences while traveling in the atmosphere or any other medium.

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