Something can be "seen" when light waves emitted or reflected by it
enter the eye--just as something can be "heard" when sound waves from it
enter the ear.
| NSES Content Standard B
Physical Science: Transfer of energy Grades 5-8, page 155 Light interacts with matter by transmission (including refraction), absorption, or scattering (including reflection). To see an object, light from that object--emitted by or scattered from it--must enter the eye. |