- The speed of sound depends on the medium through which it travels. It is related to the elasticity (stiffness) and density of the medium. - In general, sound travels faster in media where the particles are closer together and interactions between them are stronger, allowing vibrations to be transmitted more efficiently. - Gases (like air) are much less dense and less elastic than liquids (like water) and solids (like iron). - Solids typically have the highest speed of sound, followed by liquids, and then gases.