Here's why:
* Gravity depends on mass and distance. The force of gravity between two objects depends on their masses and the distance between them. The mass of the paper doesn't change when it's crumpled, and the distance to the center of the Earth (where the gravitational force is strongest) also remains roughly the same.
* Crumpling changes the surface area, not mass. Crumpling a piece of paper changes its shape and surface area. This can make it appear heavier because it's harder to lift, but it doesn't actually increase the paper's mass or the gravitational force acting on it.
What you're experiencing is air resistance. When the paper is crumpled, it has less surface area exposed to the air, meaning there's less air resistance to slow its descent. This makes it seem like gravity is stronger, but in reality, it's just falling faster.
