Shadows form when an opaque object blocks light rays from traveling in a straight line.
Essentially, a shadow is created because light cannot pass through the object. Here's a breakdown:
- Light Source: Light travels in straight lines from a light source (like the sun or a lamp).
- Opaque Object: When an opaque object (something that doesn't let light pass through) is placed in the path of the light, it blocks the light rays.
- Shadow Formation: The area behind the object, where the light is blocked, appears darker. This darker area is the shadow. The edges of the shadow are defined by the light rays that manage to graze the edges of the object.
To illustrate, imagine holding your hand up in front of a lamp. Your hand blocks the light, and a shadow of your hand appears on the wall behind it. The shape of the shadow closely resembles the shape of your hand.
- Umbra: This is the darkest part of the shadow, where the light source is completely blocked.
- Penumbra: This is the lighter, fuzzy area around the edge of the shadow. It occurs when the light source is only partially blocked. This happens when the light source is larger or the object is closer to the light source than to the surface the shadow is projected on.
In summary, shadows are formed because opaque objects obstruct the path of light.
