When light strikes an object, different things can happen. It depends on the material the object is made of.
- The light may pass straight through the object. We say that it has been transmitted. The material is transparent.
- The light may be absorbed by the object. (The object gets little warmer.) The material is opaque.
- The light may bounce off the object. We say that it has been reflected.
Sometimes two of these things can happen, or all three. For example, glass transmits light but it may also reflect some of it.
A shadow forms when an opaque object blocks the light. It forms because light travels in straight lines-it cannot bend round corners.
