What are the factors that affect the dampening of spring-mass system? I'm trying to investigate how different values of spring constant affect the changes in amplitude and period of oscillations while the spring-mass system undergoes dampening. However, I have to make sure that the way I change spring constant does not affect my experiment.


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*Does using different materials to change the spring constant affect the dampening?

*Does the mass of the spring affect dampening?

*What are other constraints?


Plus, as the spring-mass system undergoes dampening, I'm going to look at successive amplitude values to figure out the decaying constant for each value of spring constant. For different values of spring constant, if I begin with the same initial amplitude, the total energy of the system will vary. If I set the experiment so that all trials begin with the same total energy of the system, the amplitude will vary. 


*Which one (initial amplitude or total energy) should I keep constant to figure out valid decaying constant?

 A: We should remember that damping of spring mass system is due to drag from air. Many think friction is cause of dampening but you see in vertical spring mass system like weight (gravitational force) does not affect the time period to change over time similarly a constant forces are to ignored (note force must not change direction and magnitude). So we shouldn't consider constant forces as sources of dampening. We have to consider forces that are proportional to speed,speed square,distance from origin etc.(Because mathematically they will change the differential equation of constant time period to decaying time period)
So answer to your questions
1. No changing the spring material will change spring constant. It will merely add anything to drag force.


*No mass of spring will not cause dampening oscillation.
In that case time period is given by
$$ T=2π√((m(obj)+(m(spring))/3))/k$$

*The area of object is the other factor that causes mainly the drag.
$$F(drag)=(density of air)*(area)*(speed)^2$$ 
So use small bob.
4.$$E(system)=(KA^2)/2$$
I think  Try to keep amplitude constant in all trials it will  be easy to find decaying constant.And initial  energy will more if a constant larger amplitude so it will decay very less.
