Sound Waves

Sound waves are a mechanical oscillation of pressure. It is a series of vibrations that can be heard.

3,341 Questions
Sound Waves

Is silence a sound?

According to Merriam-Webster, the definition for silence is:

"1: forbearance from speech or noise2: absence of sound or noise"
Sound Waves

Why does everyone hate the sound of their own recorded voice?

It’s largely due to our voices genuinely sounding different to us on recordings than they do as we’re speaking. Sometimes, they sound so different that the speaker can’t even recognize a recorded voice as their own. This discrepancy is because as we speak, we receive that sound both externally and internally. The internal sources include lower frequencies that are excluded from external sources, so other people (and recordings) perceive your voice as higher than you do.

Those are the simple facts: Your voice sounds lower to you than it does to other people and on recordings. Why that difference is so upsetting to most of us is not as clearly understood, though. You might be displeased with the tiny emotional cues that you can only pick up by hearing your voice externally, but some research suggests that you only dislike your voice because you know it’s yours.

In other words, we could all be a little kinder to ourselves, especially in the recorded voice department.

Space Travel and Exploration
Science Experiments
Sound Waves

What is the speed of ultrasound waves in the air?

The 'normal' speed of sound is 340 m/s in dry air at room temperature and pressure.

From your question, it appears we should differentiate the terms "ultrasonic" and "supersonic".

Ultrasonic relates to sonic frequencies higher than 20 KHz, i.e. beyond audible range. For a given gas, the speed of sound is independent of the frequency of the sound measured and also independent of the density of the gas.

Supersonic relates to a speed of an object greater than the normal speed of sound (340 m/s in air at STP) and usually the phenomena associated with it.

The speed of sound is also a functionof the medium through which it's passing. For example, the speed of sound through water is 1,500 m/s, and is slightly over 5,000 m/s in iron.

So to answer your question, the speed of ultrasound in airis340 m/s for the reasons given.

Sound Waves

Do sound waves travel forever?

No, they dissipate, broken up by other waves, or simply by growing to attenuated.

They dissipate as the wavefront continues to travel farther way and the density of the energy will spread farther and farther away until it is essentially zero.

Sound Waves

How can you prevent sounds from traveling?

Sounds, once created, cannot be "prevented" from traveling. A "sound" becomes a sound only because it has already traveled, even if only for an instant. Because sounds are compression waves, they need a medium through which to travel. A sound will continue to travel until it as dispersed or been absorbed to the point that it can no longer be detected.

In a vacuum, there's an absolute lack of material. In this condition, a sound cannot even be created, let alone travel. So if you wanted to prevent a sound from occurring, attempt to make a sound in a vacuum. There will be no sound at all through the vacuum. However, even in this situation, the material you used in attempts to create a sound will transmit a sound wave.

If a sound as been generated and started travelling, it can be attenuated by absorption which limits or prevent the sound from being present although still very close to the "travelling sound". There are a variety of acoustic insulating materials that can be used for this absorption. Thick foam is used on conventional headphones to limit sound travel.

The one thing that is more effective than absorption that can be used is an active sound generator that can detect and transmit the inverse sound waves. This results in the sound waves being cancelled. This method is used by the sound-cancelling headphones.

Solid State Physics
Sound Waves

How many decibels do you need to break glass?

It is not so much the volume of the sound as the frequency as well. Sound at the wrong frequency can be played as loud as you like and it will not break the glass. The sound needs to be the same frequency as the resonant frequency of the glass (tap the glass, that note is it's resonant frequency). Once the resonant frequency has been found, it does not take much volume at all, even humans can do it, albeit trained singers (see Mythbusters).

Sound Waves

How high do you have to be to break glass?

You don't necessarily have to go so high to break a glass, rather it is hitting the exact same frequency of vibration that the glass has. So you would tap the glass to determine the frequency (you need someone with perfect pitch or an analyzer), and then you just have to hit that same note at the right intensity to break the glass.

Sound Waves

Why do theatres and cinemas have thick curtains hanging along the walls?

The curtains provide attractive sound deadening so that it doesn't echo in the theater. Some theaters just use other sound absorbing methods but the curtains are something of a hold-over from the older theaters where plays and concerts were performed in the past and have a nice appearance.

Sound Waves

How are sound waves created?

sound waves are created by producing the vibrations in air

Sound Waves

Example of pleasant sound?

Different people think that different sounds are pleasant, but here are some sounds that are often perceived as pleasant:

  • piano
  • purring
  • harp music
  • the sound of rain
  • the sound of waves crashing on the beach
Sound Waves

What is loud noise of explosion?

bang or boom

Sound Waves

How is pitch related to frequency?

The higher the frequency, the higher the pitch. The lower the frequency, the lower the pitch.

Sound Waves

If a note is 400hz. how many sound waves pass point per second?

400. Hz (hertz) means cycles per second.

Sound Waves

Is the loudness of a sound wave is related to its amplitude?

The loudness of a sound wave all depends on its amplitude. The larger the amplitude, the louder the sounds, and vice versa. Take a look at the image below.

Thunderstorms and Lightning
Sound Waves

Why do scientists not need to have perfect pitch in order to analyze sounds?

Scientists do not need perfect pitch to analyse sounds because they use instruments to detect and assess the noise.

Sound Waves

Does the whistle of a tea kettle have greater frequency than a drum beat?

Yes it does. Higher pitched sounds have higher frequencies than lower pitched sounds.

Waves Vibrations and Oscillations
Sound Waves

How do sound waves behave like the waves in spring toys?

they are different by the way they behave and the way it is different is one behaves like they should and the other one behaves bad.

Speed of Sound
Electromagnetic Radiation
Waves Vibrations and Oscillations
Sound Waves

What is the difference between heat waves and sound waves?

Heat waves are a form of electromagnetic radiation. Therefore, they are transverse waves (oscillate perpendicularly to the direction of propagation) and need no medium to travel through. Sound waves, on the other hand, are mechanical waves, meaning they need a medium to travel through. If that medium is a liquid or a gas, sound waves oscillate longitudinally (in the direction they're traveling). If that medium is a solid, they oscillate both longitudinally and transversely.

Waves Vibrations and Oscillations
Sound Waves

How can a microphone and oscilloscope show a sound wave?

The microphone reacts to changes in air pressure and creates corresponding AC electical waveforms.

The oscilloscope takes the AC waveforms and deflects a moving electron beam in a cathode ray tube, thus producing a moving display of the electrical waveform.

Sound Waves

Which equipment is most useful when measuring the two environmental changes mentioned?

A thermometer and light meter are the most useful when measuring two environmental changes.

Sound Waves

Sound waves in the range above 20000 hertz?

Such sounds are called Ultrasounds.

Sound Waves

What is the difference between reverberation and echo?

The gaps between the reflections are long when you hear an echo. When the reflections are very close together then you here no single echo, you hear many close reflections as a reverberation.

Waves Vibrations and Oscillations
Sound Waves

What is the purpose of sound waves?

cymatics? former of matter...


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