Period of oscillation for a mass on a spring

[physics20]

Why does the period of oscillation for a mass on a spring depend on its mass? (while in other situations, like a simple pendulum, the mass seems to be unimportant)

 

[hotvette]

Reason is the amount of spring deflection is proportional to the attached mass. If mass is very small, the spring doesn't deflect very much and takes a much short time to complete a cycle than if the mass was large.

 

[granpa]

because the restoring force for a pendulum is due to gravity
for a larger mass the restoring force is automatically larger.
that is not the case for a mass-spring system

 

[nasu]

Reason is the amount of spring deflection is proportional to the attached mass. If mass is very small, the spring doesn't deflect very much and takes a much short time to complete a cycle than if the mass was large.

This is a little confusing and mostly not true.
The period does not depend on the spring deflection (amplitude) and the amplitude does not depend on the mass attached but on the initial conditions.
If you have in mind a vertical spring (it does not have to be vertical) with a mass attached, then the mass determines the equilibrium deflection, but this is not in general related to the amplitude or the period of the oscillations.