Lower your head so that you are peering at the object just above and parallel to the table top with one eye. While doing this, place a pencil on the paper where your one eye sees the object and from that point trace back to your eye always keeping the pencil along the direction that you see the object. Do not change the position of the paper or the object. Move your head so that you see the object from different angles, drawing a similar line for each position. The lines you have drawn can be thought of as light rays leaving the object and entering your eye.
Rays can be helpful to illustrate many light phenomena.
Use one hand to hold a light bulb high above the table and place your other hand between the bulb and table. Describewhat you see on the table. Slowly lower the bulb. Again describe what you see. Illustrate this phenomenon in your notebook using rays.