Sound seems to travel further after dark, and the air is what cha rather th the so. By d the gro is wa and t layer ju above i is war than the air higher up, so a sound wave leaving the ground is bent upward and away from you. At night the ground cools first, the order is reversed, and the same wave is bent back down towards the surface. Nothing has become louder.

Type only the missing letters. Each box is one letter, and the number of boxes matches the letters that are missing.