Light, whether from the sun or some object, travels in a straight line.
This can be easily seen by shining a flashlight in the dark. Light rays
can bounce off materials, like walls, to provide light to other areas
like around corners.
Light is a form of energy. If you hold your hand near a light you will
feel it get hot. Some light sources can get so hot that they can burn
Some objects, like windows, are transparent allowing light to pass through
them. Other objects are opaque, blocking the light from going through