Pitch & Frequency
What term describes how high or low a sound seems to a listener?
Pitch
Which part of a sound wave (height or length) is related to how loud the sound is?
Height (amplitude)
What is the distance from one compression to the next compression in a sound wave called?
Wavelength.
Can sound travel through empty space (a vacuum)? Yes or No.
No — sound cannot travel through a vacuum because it needs particles to transfer the vibration.
What causes an echo?
An echo is caused by sound reflecting off a distant surface and returning to the listener.
Frequency measures how many of these occur each second in a sound wave. What is the name of the unit used to measure frequency?
Hertz (Hz)
True or False — A sound with larger amplitude is louder than a sound with smaller amplitude.
True
Sound waves are an example of what type of wave: transverse or longitudinal?
Longitudinal.
Which state of matter (solid, liquid, gas) generally allows sound to travel fastest?
Solids
Why can we hear thunder a few seconds after we see lightning?
Light travels much faster than sound; we see lightning first and hear thunder later because sound is slower.
If one sound has a frequency of 440 Hz and another has a frequency of 880 Hz, which sound has the higher pitch and why?
The 880 Hz sound has the higher pitch because higher frequency = higher pitch.
Two identical speakers play the same note. Speaker A has sound waves with amplitude twice as large as Speaker B. How will their loudness compare in general?
Speaker A will generally sound louder because larger amplitude means more energy and greater loudness (perceived loudness also depends on listener and environment).
Define reflection of sound and give a short example students might hear in everyday life.
Reflection is when sound bounces off a surface; example: hearing your voice bounce back in a canyon (an echo).
Explain why sound usually travels faster in solids than in gases.
Solids have particles packed more closely so vibrations transfer more quickly between particles.
A dog whistle emits sound at a frequency humans cannot hear but dogs can. Explain briefly why that is.
Dog whistles produce high-frequency sound waves above the human hearing range (humans ~20–20{,}000 Hz), but dogs can hear higher frequencies.
Explain how the frequency of a string changes when you make the string shorter while keeping tension the same.
Shortening the string raises the frequency, so the pitch becomes higher.
Describe one way a musician can change the loudness of a note on a wind instrument.
Increase air pressure/blow harder to increase amplitude; decrease to play softer.
What is interference of sound waves? Give a simple example using two identical tones played together.
Interference is when two waves meet and combine — they can add (constructive) or cancel (destructive); e.g., two identical tones in phase become louder.
A sound travels through air at about 343 meters per second at room temperature. How far does that sound travel in one second? (Answer with a simple statement.)
It travels 343 meters in one second (about 343 m).
Describe how a musical instrument like a guitar produces different pitches on different strings.
Different strings have different lengths, thicknesses, and tensions which change frequency; plucking a shorter, tighter string produces a higher pitch.
A tuning fork vibrates at 256 Hz. Describe what happens to the pitch you hear if you place the tuning fork near the opening of a long empty tube that resonates at the same frequency.
The tube will resonate and make the sound louder at that frequency; you still hear the same pitch but possibly stronger due to resonance.
Explain why moving farther away from a loudspeaker makes the sound quieter, using the idea of amplitude and energy spreading out.
As distance increases, the wave energy spreads over a larger area so amplitude decreases and the sound becomes quieter.
Describe how wavelength, frequency, and speed of sound are related, and write the relationship using symbols (use f for frequency, \lambda for wavelength, and v for speed).
Relationship: v = f \lambda (speed equals frequency times wavelength).
Describe how temperature affects the speed of sound in air and give a short reason why.
Higher temperature usually increases the speed because particles move faster and transmit vibrations more quickly.
Explain how sonar (used by submarines or bats) uses sound to find objects, including the role of echoes and timing.
Sonar sends out sound pulses and listens for echoes; by measuring the time between sending and receiving the echo and knowing the speed of sound, distance to an object can be calculated.