How Sound Travels

Sound is produced by vibrating objects and travels as a longitudinal mechanical wave. It propagates through compressions (high pressure) and rarefactions (low pressure) in a medium. It cannot travel through a vacuum.

Characteristics of Sound Waves

Sound waves are characterized by their wavelength, frequency, amplitude, and speed. The frequency determines the pitch, while the amplitude dictates the loudness. Sound travels fastest in solids and slowest in gases.

Reflection and Ultrasound

Like light, sound reflects off surfaces. Distinct reflections heard after a delay are called echoes, while prolonged reflections cause reverberation. Frequencies above 20 kHz (ultrasound) have incredible applications, from medical echocardiography and ultrasonography to SONAR used by ships and submarines.

The Human Ear

Our ears collect pressure variations in the air, converting them to physical vibrations via the eardrum and tiny bones. The cochlea translates these vibrations into electrical signals that our brain interprets as sound.