As light creates color, it also creates form by organizing the darks into shapes known as shadows. the brighter the light the greater the value range and the harder the shadow form. The softer the light, the softer the shadows and the value range is less.
Notice that the shadow is larger than the object because the light source is so close You should also see that the shadow is smaller as the light source is farther away
Lastly, the shadow is very long and projected as the light source is placed at a low angle. Shadows are most intense right next to the object that casts them and diminish in darkness as they move away. This is due to the bounce light that comes into play as the shadow moves away from its source.