Resonance: When you sing, you use your vocal cords to produce sound. The vocal cords vibrate, creating sound waves that travel through the air. These sound waves can resonate with the walls of your vocal tract, creating a richer and fuller sound.

Harmonics: When you sing, you produce a fundamental frequency, which is the lowest pitch that you hear. In addition to the fundamental frequency, you also produce a series of higher frequencies, called harmonics. These harmonics are multiples of the fundamental frequency and create a more complex and interesting sound.

Loudness: The loudness of your singing is determined by the amplitude of the sound waves. The amplitude is the measure of how much the sound waves displace air molecules as they travel. The greater the amplitude, the louder the sound.

Timbre: The timbre of your singing is determined by the relative strength of the different harmonics that you produce. The timbre is what makes your voice sound unique.

Doppler Effect: When you sing, the sound waves that you produce travel away from you in all directions. As these sound waves travel, they spread out, causing the pitch of the sound to change slightly. This change in pitch is called the Doppler effect.