Elevator
Standing on a scale in an elevator at rest (or in constant motion), we have a statics problem in one dimension: S Fy = +Fscale - mg = 0.
The scale reads the contact force that the scale is exerting. In this case, it is easy to see that the force of the scale balances your weight, and so the scale reads your weight:
Fscale = mg = 70 kg * 9.8 m/s2 = 686 Nt.