Physics education research, electronic materials, and the musings of Christopher Moore, Ph.D.

Light inside a box will be falling in the gravity inside the box. Anything that is falling is weightless. Light always falls so it is always weightless. When light is absorbed by the side of the box an electron gets heavier so the box gets heavier until that light is reradiated into freefall inside again.

The box is only heavier when the light becomes the mass of the box at absorption.

Mitch Raemsch