6.1 Loudness and pitch of sound

• A large wave has more energy than a small one, so we hear larger waves as louder sounds.
• Loudness depends on the amplitude (or size) of the waves that make up the sound
• The loudness of a sound is measured using decibels (dB).
• Amplitude: In a wave, the maximum displacement or distance moved by a point on the wave from its equilibrium position. In simpler terms, it represents the height of a wave from its resting position to its crest or trough.
• Frequency: The number of complete oscillations per second of a periodic motion or vibration.
• Pitch: A subjective sensation produced when hearing certain frequencies of sound; high-pitched sounds have higher frequency while low-pitched sounds have lower frequency.
• Frequency: The number of complete cycles of a wave that occur in one second. It is measured in Hertz (Hz) and represents how many times a wave repeats itself within a given time frame.
• Loudness: A subjective measure of the intensity or volume of a sound wave as perceived by the human ear. It is determined by the amplitude of the sound wave, with greater amplitudes generally perceived as louder sounds.
• Oscilloscope: An electronic instrument used to graphically display and analyze the waveform of electrical signals. It shows how voltage changes over time, allowing visualization of various electrical phenomena.
• Peak: The highest point or maximum value reached by a waveform, typically corresponding to the crest of a wave.
• Pitch: A perceptual attribute of sound that corresponds to the frequency of the sound wave. Higher frequencies are perceived as higher pitches, while lower frequencies are perceived as lower pitches.
• Trough: The lowest point or minimum value reached by a waveform, typically corresponding to the lowest point between two crests of a wave.
• Waveform: A graphical representation of a wave that shows how a physical quantity (such as voltage or displacement) varies with time. It displays the shape, amplitude, frequency, and other characteristics of a wave.
• What: Sound is the result of vibrations in objects, which create waves of pressure fluctuations in a medium, such as air molecules. These waves propagate through the medium and are perceived by our ears as sound.
• Why: Understanding the scientific principles behind sound production helps elucidate a wide range of natural and technological phenomena, including acoustic communication, musical instruments, and medical diagnostics.
• When: This concept is applicable whenever sound is encountered or when activities involve the generation, transmission, or reception of sound waves.
• Sound is generated when an object vibrates, causing adjacent air particles to oscillate
• The magnitude of vibrations, known as amplitude, determines the loudness of the sound
• Larger amplitudes produce louder sounds
• The frequency of vibrations dictates the pitch of the sound
• Higher frequencies result in higher pitches
• Sound waves can be graphically represented with peaks and troughs
• Peaks correspond to regions of maximum pressure fluctuations
• Troughs correspond to regions of minimum pressure fluctuations
• Instruments like oscilloscopes visualize sound waveforms
• Oscilloscopes provide insights into the temporal characteristics of sound propagation
• How: By understanding the properties of sound waves, we can manipulate them to achieve desired effects, such as amplifying sounds using speakers or reducing unwanted noises using earplugs.
• Sound travels at different speeds depending on the material it passes through. In solids, sound travels faster than in liquids, and fastest of all in gases.
• Particles in the medium, such as air, move back and forth as sound waves pass through, compressing and rarefying in response to the changing pressure. The amplitude of a sound wave represents the maximum displacement of these particles from their equilibrium position during the passage of the wave. Troughs in a sound wave correspond to the points of minimum pressure, where particles are most spread out, while peaks indicate maximum pressure points, where particles are most compressed.
• Why: Understanding how sound travels through different media is important because it helps us understand why some sounds are louder than others and how they travel over long distances.
• Pitch, which is related to the frequency of the sound wave, describes how high or low a sound appears on a musical scale. Higher frequencies produce higher pitches, while lower frequencies produce lower pitches. For instance, a sound wave with a frequency of 500 Hz indicates that 500 vibrations occur per second.
• By manipulating the amplitude and frequency of sound waves, we can control the perceived loudness and pitch of sounds. Understanding the underlying principles of sound production and transmission enables us to manipulate and harness sound waves for diverse applications, such as in audio engineering, telecommunications, and environmental monitoring.
• Sound waves are vibrations that pass through the molecules of a medium
• Sound waves are longitudinal waves that travel as a series of compressions and rarefactions
• Compressions are regions where vibrating particles are closest together, while rarefactions are regions where particles are furthest apart
• Sound waves travel through solids by causing particles inside the solid to vibrate and pass on the vibrations to their neighbors
• The speed of sound is faster in solids, slower in liquids, and slowest in gases due to the density of particles
• As sound waves pass between different mediums and speed up or slow down, their frequency remains the same while the wavelength changes
• Sound can be refracted, reflected, and absorbed, with hard flat surfaces reflecting most, creating echoes
• Human hearing involves sound waves traveling through the ear canal, vibrating the eardrum, transmitted through ossicles, semicircular canals, and into the cochlea