Vibrations: Imagine dropping a pebble in a still pond. Ripples spread out from the point of impact, right? Sound waves behave similarly. A vibrating object, like a loudspeaker diaphragm, creates tiny fluctuations in pressure in the surrounding medium. These fluctuations travel outwards as the source continues to vibrate.

Compressions and rarefactions: As the sound wave travels, the medium doesn't move smoothly forward. Instead, the particles of the medium get squeezed together (high pressure zones) and pulled apart (low pressure zones) in a repeating pattern. These zones are called compressions and rarefactions, respectively.

Longitudinal waves: Unlike waves in water that travel up and down, sound waves are longitudinal. This means the particles in the medium vibrate back and forth in the same direction as the wave propagates, rather than moving perpendicular to it.

Different properties of sound waves are related to how we perceive sound:

• Frequency: This refers to how many times per second the pressure fluctuates. High frequencies correspond to high-pitched sounds, while low frequencies sound low-pitched.

• Wavelength: This is the distance between two consecutive compressions (or rarefactions) in the wave. Wavelength is inversely proportional to frequency. So, longer wavelengths create lower-pitched sounds.

• Amplitude: The amplitude of the sound wave is related to its intensity, or how loud we perceive the sound. Larger pressure variations correspond to louder sounds.

By understanding sound waves, we can explain things like how sound travels at different speeds in different mediums, how sound reflects and echoes, and even how different instruments create sounds with varying characteristics.