sound and light Flashcards
Distinguish between transversal and longitudinal waves
Transverse Waves:
- Waves where particles of the medium move perpendicular to the wave direction.
- Examples: Light waves, water waves.
- Visualize shaking a rope horizontally; the wave moves up and down, with the disturbance traveling sideways.
Longitudinal Waves:
- Waves where particles of the medium move parallel to the wave direction.
- Examples: Sound waves, seismic waves.
- Picture compressing and stretching a slinky; the wave moves in the same direction as the slinky’s coils, creating compression and rarefaction zones.
Describe, give units and be able to identify the main features of a wave: wavelengths,
frequency and amplitude
Wavelength (λ):
- Definition: Distance between two consecutive points in a wave that are in phase.
- Units: Usually measured in meters (m), millimeters (mm), or kilometers (km).
- Identification: Distance from one peak (or trough) to the next peak (or trough).
Frequency (f):
- Definition: Number of complete cycles passing a fixed point in one second.
- Units: Typically measured in Hertz (Hz), where 1 Hz equals one cycle per second.
- Identification: Indicates how many waves pass a fixed point per unit time.
Amplitude (A):
- Definition: Maximum displacement of a wave from its equilibrium position.
- Units: Usually measured in meters (m) for transverse waves and pressure units (like Pascals, Pa) for longitudinal waves.
- Identification: Represents the intensity or strength of the wave. In transverse waves, it’s the distance from the equilibrium position to the crest or trough. In longitudinal waves, it’s the maximum compression or rarefaction from the equilibrium position.
Describe the relationship between amplitude and loudness
Amplitude:
- Maximum displacement of particles from their resting position in a wave.
- In sound waves, it represents the maximum variation in air pressure caused by the wave.
Loudness:
- Perceived intensity or volume of a sound wave.
- Subjective perception of how “loud” a sound is.
Relationship:
- Direct relationship between amplitude and perceived loudness.
- Increase in amplitude leads to an increase in perceived loudness, as it indicates greater variation in air pressure.
- Decrease in amplitude results in decreased perceived loudness.
Describe the relationship between frequency and pitch
Frequency:
- Number of complete cycles of a wave passing a point in one second.
- Measured in Hertz (Hz), where 1 Hz equals one cycle per second.
Pitch:
- Perception of how high or low a sound is.
- Subjective quality associated with the frequency of sound.
Relationship:
- Direct relationship between frequency and pitch: higher frequencies result in higher pitches, and lower frequencies result in lower pitches.
- Increase in frequency leads to higher pitch perception.
- Decrease in frequency leads to lower pitch perception.
Describe an experiment to be able to calculate the speed of sound
Speed of sound (v) = Distance (D) / Average time (t_avg).
Compare the speed of sound in solids, liquids and gases
Solids:
- Fastest speed of sound.
- Particles tightly packed, allowing quick transmission of vibrations.
- Example: Speed of sound in steel is approximately 5,960 m/s.
Liquids:
- Slower speed of sound compared to solids, but faster than gases.
- Particles less tightly packed than in solids, resulting in slower vibration transmission.
- Example: Speed of sound in water is approximately 1,480 m/s.
Gases:
- Slowest speed of sound.
- Particles widely spaced, leading to slower transmission of sound waves.
- Example: Speed of sound in air at room temperature is approximately 343 m/s.
Comparison:
- Speed of sound: Fastest in solids, slower in liquids, slowest in gases.
- Determined by particle density and arrangement in each state of matter.
Explain materials that absorb and reflect sound and discuss their application in sound
proofing and echo location
Materials that Absorb Sound:
- Soft, porous materials like foam, fiberglass, and fabric trap sound waves and convert their energy into heat, reducing reflection.
- Thick curtains, acoustic panels, and carpeting can also effectively absorb sound waves, especially low-frequency ones.
Materials that Reflect Sound:
- Smooth, hard surfaces such as concrete, glass, and metal reflect sound waves, leading to echoes and reverberation.
- Reflective barriers like metal sheets or glass panels bounce sound waves away, preventing them from passing through.
Applications in Soundproofing:
- Absorbing materials are used to reduce sound transmission between rooms, while reflective materials create barriers to block outside noise.
- For example, sound-absorbing panels on walls can reduce noise transfer, while soundproof windows or doors made of reflective materials block outside noise.
Applications in Echo Location:
- Absorbing materials are used in environments like recording studios to reduce echoes and reverberations, improving sound quality.
- Reflective materials are used in echo location systems like sonar or radar to bounce sound waves off objects and detect their distance and location based on return time.
Label the structures of the ear
- Auricle: Collects sound waves and directs them into the ear canal.
- Ear Canal: Carries sound waves from the auricle to the eardrum.
- Tympanic Membrane: Vibrates in response to sound waves and transmits vibrations to the middle ear.
- Middle Ear: Includes ossicles (Malleus, Incus, Stapes) which amplify and transmit vibrations.
- Eustachian Tube: Connects the middle ear to the nose, equalizing air pressure.
- Inner Ear: Contains the cochlea, which converts sound vibrations into electrical signals.
- Vestibular System: Responsible for balance and spatial orientation.
- Auditory Nerve: Carries signals from the cochlea to the brain for interpretation as sound.
Describe the hearing range for humans
The human hearing range typically spans from 20 Hz to 20,000 Hz, covering both low and high frequencies. However, this range can vary based on factors like age and exposure to loud noises. With age.
Describe the hearing defects that can result from loud noises
Prolonged exposure to loud noises can cause permanent hearing loss (NIHL), tinnitus, increased sensitivity to sounds (hyperacusis), and auditory processing disorders. Temporary hearing loss (TTS) can occur immediately after exposure but may become permanent with repeated loud noise exposure.
Explain how light transfers through different materials: transparent, opaque, translucent
Transparent materials like glass and clear plastics allow light to pass through without scattering or absorption, enabling clear vision. Opaque materials such as metals and wood absorb or reflect light, blocking vision. Translucent materials like frosted glass let some light through but scatter it, resulting in blurred images.
List the colours that make up the spectrum of light
Red
Orange
Yellow
Green
Blue
Indigo
Violet
Describe dispersion of white light using a prism
White light entering a prism slows down and bends due to refraction. Different colors in the light bend by varying amounts because of their different wavelengths. This causes them to spread out or separate as they exit the prism, forming a spectrum. The spectrum ranges from violet (bent most) to red (bent least). Colors do not recombine into white light unless recombined by another prism or lens.
Explain how rainbows are formed
Rainbows are formed when sunlight is refracted, or bent, and then reflected inside raindrops. When sunlight enters a raindrop, it bends, separates into its component colors, and then reflects off the inside surface of the drop
Describe how colour is seen in terms of absorption of different colours
White light interacts with objects via absorption, reflection, and transmission, influencing perceived colors. Cones in our eyes detect wavelengths, conveying color signals to the brain. Mixing colors combines reflected wavelengths, shaping our perception of color.
