Forming shadows require an object to block the movement of light. We see everything because of light, that electromagnetic wave that allows us to view the object. For example, if you stand on the sidewalk, you are able to see the pavement before you because the light that hits its surface bounces back to your eyes.

But if you stand over the spot, the passage of the light will be blocked by your physical body, forming shadows. The shadow, therefore, is that part of any object which light cannot access. Perhaps an even better example would be a room. Turn on the light and you will see everything; turn it off and there is darkness. If you use a low key light, then several shadows will appear.

Although light (or the lack of it) is responsible for forming shadows, there are other things that help determine the shape and size of it. In particular if the angle of the light and the object is around ninety degrees. If the angle of the light is smaller, then the shadow will be much longer than normal. If the object that is blocking the path is very near the light source, a larger shadow will appear.

The size of the shadows of course, will also be determined if the object is in motion. Usually the size of the shadow will be slightly longer or larger than the moving object.

The size of the light source is also crucial in forming shadows. If it is big, then expect the shadows to be more blurry. Other factors that will come into play will be other light sources or effects that may cause the light to bend. If the light source emanates from numerous directions and points, you will see several shadows, some of them overlapping. Depending on the color of the light, you will also see shadows of different lights and shades.

Colored shadows, for the most part, are generated when the multicolored light sources produce white light. If there is no white, the complementary hue for the lights that are being blocked will be reflected on the shadow. For example, if the light is blue, then the shadow that will appear is red, while for green, it can be yellow or purple, depending on the shade.

With these explanations, it should be obvious why the time of day plays a vital role in forming shadows, the sun being the primary source of light on the objects around you. However, it would be appropriate to dismiss a myth here right now, which is that shadows get longer as the day fades. The opposite is in fact the case.

Knowledge is power, it is said, and this is certainly true in this case. The next time that you are forming shadow puppets on the wall, you will have a better idea of how these tricks of light are formed.