Why does a shadow become more fuzzy when the object that casts the shadow is further removed from the surface it casts the shadow on?

Question

Why isn’t a shadow as sharp as one can see the object?

In: Physics

Answer 1

Imagine a long narrow triangle. Right near the “point”, the two sides are next to each other, but down by the “base” the two sides are much further apart, right?

That’s what’s happening. The object itself is the “point” of the triangle, the shadow is the “base”, and light streaming past the object is lots and lots of sides. When the object is closer to the shadow, the light doesn’t spread as much, but when the object is farther away the light spreads out a lot more before hitting the surface that the shadow is on.