Here's why:

* Neutral Charge: An uncharged electroscope has an equal balance of positive and negative charges.

* Repulsion: Like charges repel each other. If the leaves were charged, they would repel each other and spread apart.

* Gravity: Since the leaves are not charged, they are only affected by gravity, which pulls them straight down.

Think of it this way: the leaves are like two pieces of string hanging from a point. When they have no charge, they simply hang straight down due to gravity.