Understanding Sound and Wave Properties

Understanding Sound

Sound Intensity

Intensity (dependent on size): Distinguishes between strong and weak sounds. Physical intensity relates to the energy carried by the sound wave.

Auditory Intensity: This is the sensation perceived by our ears, and it depends on physical intensity and other factors.

Timbre

Timbre depends on the waveform. Physically, a sound's timbre depends on its wave composition.

Noise Sources

A sound source is any vibrating body that can produce elastic waves in the surrounding environment.

Properties of Sound

Reflection

Sound waves reflect when they encounter a hard surface.

Echo

An echo is the repetition of a sound due to its reflection.

Refraction

Refraction is the deviation of sound waves in air layers of different temperatures.

Diffraction

Diffraction allows us to hear someone talking in a side room.

Interference

Sound waves can interfere with each other, resulting in strengthening, weakening, or cancellation depending on the conditions.

SOUND + SOUND = SILENCE (under specific interference conditions)

Absorption

Sound absorption is the process of sound energy being absorbed by a material.

Noise

Noise: A sound or combination of mixed and messy sounds that lack a constant wavelength, frequency, or amplitude, and are randomly distributed.

NOISE WAVE IS MADE UP MESSY

Noise Pollution

Noise pollution is the collection of sounds and noises circulating in the air throughout populated areas.

SOME NOISES ARE ABOVE THE THRESHOLD OF PAIN (120 dB)

Waves

What is a Wave?

A wave is a disturbance that spreads through space. The physical characteristics of the medium (elasticity, density, temperature) determine the speed of wave propagation. Waves can also propagate in other forms, such as light, radio waves, and X-rays, which are called electromagnetic waves.

Classification of Waves

Based on Nature

• Mechanical Waves: These waves require a physical medium to propagate. Sound is an example of a mechanical wave. The medium must be elastic and have inertia.
• Electromagnetic Waves: These waves do not require a physical medium and can travel through a vacuum at 300,000 km/s. Examples include X-rays, radio, and TV waves.

Based on Direction of Oscillation

• Transverse Waves: Particles oscillate perpendicular to the direction of wave propagation (e.g., "the wave" in a stadium).
• Longitudinal Waves: Particles oscillate in the same direction as wave propagation, vibrating back and forth.