Physics

Physics is a study of nature. The physical science view the nature as a dead or mechanical [ Strongly ruled by measuring mathematics ] object/collection of objects.

Every thing in the Nature is just a mechanism and the Nature is a huge machine with sub-parts .  

Now what is a device ? 

A machine is an object with Input Process Output cycle.

But we practically call a machine as a device when it reduce human effort. 

Whatever, Universe if full of machines . The sun , moon , gas to Living being all are ruled by some laws on some measurable properties. 

The Nature follows some rule -

1) Physical Laws are true irrespective of space and time in all Inertial Frames .

2) Uncertainty :- There are pairs of physical quantities where each member of the pair cannot be determined with absolute certainty .

For example : - momentum p(x) and position x . 

                         it is known from  Heisenberg principle that σ(x)σ(p(x))  ≥ h/4π