Our lessons resumed after a period of rest.
"I hope you guys are well rested because we'll be moving on to a new Topic Today" my Dad said.
"What will we be learning Today Dad" Ariel asked.
"Today, I'll be teaching you about Light and Shadow and the relationship they have to each other" my Dad said.
"We're ready" I said.
"As I explained earlier, Material Light typically flows in straight lines. When the Rays Of Material Light make contact with any body, visibility of the body is granted. How visible the body is depends on the phenomena of Transparency or Reflection it may exhibit" my Dad explained.
We paid close attention.
"When Light makes contact with a body that exhibits complete Transparency, two things happen. The first is that the body is rendered completely invisible. The second phenomenon is that the body casts no Shadow at all" my Dad explained.
"I see. It's like Air for instance. We can feel it but we can't see it. Air typically casts no Shadow" I realized.
"On the other hand, when Light Rays make contact with a body that reflects the Rays, a Shadow is cast in the opposite direction from which the Light Rays making contact with the body are reflected. Simply put, when Light hits a body from the front, a Shadow is cast behind the body. When Light hits a body from the Right, a Shadow is cast to the Left of the body. If the Light were to make contact with the body from Above, a Shadow would be cast below the body and vice versa" my Dad explained.
"In other words, a Shadow is cast in the opposite direction from which the Light hitting the body is reflected isn't that so Dad?" Ariel asked.
"You're very perceptive Ariel. This is true" my Dad said. "How dark the Shadow cast by the body is, is to a large extent dependent on the phenomena of Transparency and Reflection acting on the body. The greater the phenomenon of Transparency acting on the body, the fainter the Shadow is. As you noted earlier San, it's for this reason that Air though we can feel and acknowledge its presence is both invisible and casts no Shadow at all. It's because it is completely Transparent. On the other hand, the greater the phenomenon of Reflection acting on a body, the darker the Shadow cast by the body is. In other words, when a body allows the maximum amount of Light to flow through it, it casts no Shadow at all. When a body allows some Light through while reflecting the rest, the Shadow cast is faint when the Light passing through the body is greater than the Light reflected by the body and dark when the Light reflected off the body is greater than the Light passing through the body. However, when a body reflects the maximum amount of Light flowing towards it instead of allowing the Light through, the body casts a dark Shadow. Transparent Objects thus cast no Shadow at all. Translucent Objects cast faint Shadows while Opaque Objects cast dark Shadows" my Dad explained.
"I see, so Air casts no Shadow because it is completely Transparent. Water casts a faint Shadow because it's Translucent and a Tree for instance would cast a dark Shadow because it's Opaque huh?" I realized.
"Exactly but like I explained earlier, the phenomena of Transparency and Reflection also determine how visible an object is. You could say in reverse that objects that cast no Shadow at all are completely invisible. Those that cast faint Shadows are partially visible while objects that cast dark Shadows are completely visible" my Dad explained.