what property of light allows shadows to form?
Light travels in straight lines. When the light hits the object it is stopped, but the light at the edges continue to travel in a straight line so there is a shadow. The shadow is not black because another property of light. It can be reflected. When it hits an object some light is reflected. If the object is not perfectly smooth the light is scattered when it reflects. Light is reflected more from light colored objects than darker objects. So in a well-lit area where there are plenty of surfaces the shadow will be less dark. A further property of light is that it will slightly bend around the corners of sharp objects. So if you look carefully you will see that the edges of a shadow are sometimes blurred. Usually this property is observed in the physics lab. Blurred edges of a shadow are more likely to occur from multiple light sources making a superimposed shadow.
Light is normally radiated on a straight light. Gravity can affect light and actually bend the beam. It can also be reflected or re-directed by mechanical means. The reason that shadows are formed is when a solid object blocks the light, preventing the beams from continuing. The blocked light is represented by a shadow.
