Question

sound waves belong to a group called mechanical waves - specifically, longitudinal waves. this means they need a material, called a medium, to travel through - unlike light waves that can pass through empty space. sound waves include compressions, where particles are pressed together, and rarefactions, where they spread out.
the speed of sound changes depending on the material it travels through. it moves faster through solids because the particles are packed closely together, making it easier for the energy to pass through. liquids come next, and sound waves move slowest through gases due to the spaced - out particles.

choose the correct answer.
why do sound waves travel fastest in solids?
a solids particles are very close together.
a solids particles are very far apart.
a solids particles are nonexistent.

Explanation:

Sound waves are longitudinal waves that need a medium to travel. In solids, particles are closely packed. This allows energy (sound) to transfer quickly as particles can easily collide and pass on the vibration. In liquids, particles are less closely packed than solids but more than gases. In gases, particles are far apart, making sound travel slowest. So, the closeness of solid particles enables faster sound - wave travel.

Answer:

A. A solid's particles are very close together.