Miraculous Ladybug - Tendencies series - set somewhere in the last chapter of Quiver.
Rating: Safe for Moon. Not safe for Adrien.
“The speed of sound depends on the medium the sound is travelling in. Sound travels faster in solids than in liquids, and faster in liquids than in gases. This is because the density of solids is higher than that of liquids which means that the particles are closer together—”
Adrien blinked slowly as he watched Madame Mendeleiev conduct her lecture on sound. Physics generally interested him, but today he found it difficult to concentrate. He’d felt… odd… ever since Kim walked into the classroom at the beginning of class.