Stokes' Law: Why does viscous drag depend upon the radius of the spherical body?

[Kaushik]

Stokes' Law gives us the value fo viscous force when a spherical body is under motion inside a fluid.
$F_{viscous} = 6\pi\eta av$ (where $a$ is the radius of the spherical body and $v$ is the velocity with which it is moving)
What is the reason for the Viscous drag to depend upon the radius of the spherical body?

 

[BvU]

The more area, the more grip !

 

[Kaushik]

The more area, the more grip !

Is it like, more the area, more fluid in contact. Hence, it pulls more fluid with it, consequently the reaction force by the fluid on the body is more?

 

[BvU]

Yep !
Dutch expression: "big trees catch a lot of wind"

 

[sophiecentaur]

WORK DONE on the fluid the sphere is moving through depends on area.