Here's why:

* Density and Molecular Spacing: Gases have much lower density and greater spacing between molecules compared to solids. This means sound waves have to travel through more "empty space" in a gas, which slows them down.

* Intermolecular Forces: Solids have stronger intermolecular forces holding their molecules together. This allows vibrations (which is how sound travels) to transfer more efficiently and quickly through the solid.

Think of it this way: Imagine trying to pass a message along a line of people. If the people are close together (like in a solid), the message travels quickly. If they are far apart (like in a gas), the message takes longer to get across.