Why does a scale give a different reading in an accelerating elevator?

A scale measures the normal force exerted by the surface of the scale on an object placed upon it. In an accelerating elevator, the forces acting on a person standing on the scale change, which alters the normal force that the scale reads. When the elevator accelerates upwards, the scale shows a higher reading because both the gravitational force and the additional force due to the elevator's upward acceleration act together, resulting in an increased normal force. Conversely, if the elevator accelerates downwards, the reading on the scale decreases because the normal force is reduced by the downward acceleration, opposing the gravitational force. This variation in the scale's reading accurately reflects the total force acting on the individual, which includes the effects of both gravity and the elevator's acceleration. This principle demonstrates how the interaction between gravitational force and the applied force from the acceleration alters the perceived weight as measured by the scale.