Sound waves are mechanical waves that propagate by vibrating particles in a medium, unlike electromagnetic waves which do not require a medium. This property is essential in differentiating sound from other types of waves.

Sound requires a material medium to propagate because it travels via vibrations of particles within that medium. In a vacuum, there are no particles to transmit these vibrations, so sound cannot travel.

Frequency is directly related to the pitch of a sound wave, with higher frequencies resulting in higher pitches and lower frequencies in lower pitches. This relationship is fundamental to our perception of sound.

Amplitude determines the energy carried by a sound wave, which our ears interpret as loudness. Higher amplitude corresponds to a louder sound, while lower amplitude results in a softer sound.

Sound waves travel faster in water than in air because water is denser and more elastic. This change in medium properties results in a higher propagation speed for sound in water.

The fundamental equation for wave motion is Speed = Frequency × Wavelength. This relationship is key to understanding all types of waves, including sound.

The Doppler Effect accounts for the variation in perceived frequency (and thus pitch) when there is relative motion between a sound source and an observer. This effect is commonly experienced whenever a sound source like a vehicle passes by.

When two sound waves that are identical but 180 degrees out of phase meet, they cancel each other out, resulting in destructive interference. This cancellation diminishes or nullifies the overall sound.

Sound intensity is measured in decibels (dB), which is a logarithmic unit that quantifies how loud a sound is relative to a reference level. This unit is commonly used due to the wide range of human hearing.

Sound speed in a medium depends on both its density and elasticity. Although solids are denser, their higher elasticity allows sound to travel faster compared to gases.

Diffraction refers to the bending and spreading of waves when they encounter obstacles or pass through narrow openings. This phenomenon allows sound to be heard even when the source is not directly visible.

Warmer air has more energetic molecules, which transmit sound vibrations more rapidly. This increase in molecular activity leads to a higher speed of sound in warmer conditions.

Resonance occurs when an object vibrates at its natural frequency, amplifying those specific frequencies. This amplification is crucial in musical instruments to produce a rich and sustained sound.

The pitch of a vibrating string is determined by its frequency, which is influenced by factors like tension, length, and mass per unit length. These physical properties dictate how rapidly the string vibrates and hence the pitch produced.

When two sound waves of slightly different frequencies interfere, they produce beats - periodic variations in sound intensity. The beat frequency is the difference between the two frequencies, resulting in a wavering sound pattern.

Using the formula Speed = Frequency × Wavelength, multiplying 500 Hz by 0.68 m gives 340 m/s. This value is typical for the speed of sound in air under standard conditions.

Increasing the effective length of the air column in a closed tube lengthens the wavelength of the sound produced, which inherently lowers its frequency. A lower frequency is perceived as a lower pitch by the human ear.

When reflected sound waves interact with incoming waves, standing waves can form, creating nodes (quiet zones) and antinodes (loud zones). This fixed interference pattern is a classic demonstration of wave behavior in confined spaces.

The inverse square law dictates that the intensity of sound decreases proportionally to the square of the distance from the source. Consequently, doubling the distance reduces the sound intensity to one-fourth of its original value.

Acoustic impedance is a property that determines how much sound is transmitted or reflected at the interface between two media. A greater mismatch between the impedances causes more sound energy to be reflected rather than transmitted.