For the fifth day of Blogmas, I will be discussing the physics of singing Christmas carols. When someone is singing, they emit sound waves. Because sound waves are mechanical waves, they are required to travel through a medium. When traveling through this medium, the particles vibrate creating a frequency which is measured in vibrations per second or hertz. In turn, the higher the frequency, the higher the pitch of the singer. The loudness or quietness of the singer is measured by the amplitude of the wave. The larger the amplitude, the louder the voice of the singer. Who knew so much went into singing Christmas carols?