Sound Waves

I would expect any movement of matter to cause some sound.

amplitude

The amplitude of a sound wave determines its loudness or volume. A larger amplitude means a louder sound, and a smaller amplitude means a softer sound.

The auditory canal allows sound to get to the eardrum.

By the frequency. The higher the frequency, the shorter the wavelength. The lower the frequency the longer the wave length.

C= L * f

C = Time in milliseconds (343 m/s @ 20 degrees C , L= Wave Length or Lambda in meters and f= frequency in Hertz

A little algebra and you have;

L= C/f

Example; 343 m/s / 100 Hz = .343 meters

Frequency is a function of time, cycles per second. Time is the reciprocal of frequency

(1/f= T).

Something must vibrate, to make the air (or whatever else the sound travels through) vibrate.

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.

Often both.

pinna

the interaction between sound waves is called interference.

No

Not much, but interestingly enough, the reverse has been used on aircraft carriers.

When the fighter is approaching the carrier to land, the carrier will be sailing forwards reasonably fast. The airflow over the deck of the carrier will descend sharply just behind the flight deck, and the fighter will be pressed down by this airflow - which could lead to the approach being too low.

The carrier can emit a series of high volume audio chirps at a few kilohertz, and this compression wave will alter the density of the air behind the carrier. This slight difference in air pressure can be detected by radar, thus the actual airflow may be seen. This info is then embedded in the data fed to the pilot as he approaches the landing zone.

sound waves are created by things that make sounds like sombody speaking or instruments. water waves are created by wind.

From a wave model perspective, the intensity of a sound (i.e. its "loudness") is dependent on the amount of energy that the sound wave carries. The energy of the wave is proportional to the amplitude, how far the wave goes up and down. Thus, the intensity of voice is dependent on how much force you applied to the air passing through your vocal cords, thus displacing them more (thus a bigger amplitude). Try it, put your hand to your throat and feel which sound is more noticeable (when you whisper, or when you shout).

The energy in a sound wave is both kinetic and potential.

Just as in a vibrating spring, the medium has mass and moves and so moving mass is kinetic energy.

Just as in the spring there is compression and rarefaction, so there is elastic potential energy.

In fact, these two are equal, potential energy = kinetic energy, just like a spring.

Just like in a vibrating spring, the total energy is constant and equal to the average kinetic energy plus the average potential energy.

Wavelength in waves refers to the distance between two corresponding points on a wave, such as from peak to peak or trough to trough. It is a measure of the length of one complete cycle of the wave and is typically denoted by the symbol λ (lambda).

what are the 2 important charactristics of sound? what are the 2 important charactristics of sound?

When a 440 Hz sound is sent through steel, a wavelength of 11.6 meters is measured. What is the velocity of the sound through steel

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.

Its volume or how loud it is.

false

If you hold a lit match in front of a sub woofer that is producing low frequency sound waves you should see the fire move. Also, if you hold your hand in front of the sub woofer you should feel vibrations. These vibrations are caused by the particles in your hand moving due to the sound wave produced by the sub woofer. I think these examples are simple proof that sound waves can move things :) Although, it is sound, it is also energy. Remember, energy is never created or destroyed; it only changes form. In this case, electomagnetic energy is changed into sound waves. Energy is still energy, no matter what form. This being said, the energy produced by a sound wave is a lot less powerful/useful than something like combustion which is why we use combustion for our main means of moving things (think transportation). Hope this helps!

yes it is true for all waves.

Sound waves are carried throw the air. But sound waves can also travel throw liquids, such as water, and even through solids.

The sound of a normal conversation is 60dB (decibels) and a close range jet is 140dB. This makes a jet at close range over 2 times as many decibels than a close range jet.

The sound of a normal conversation is 60dB (decibels) and a close range jet is 140dB. This makes a jet at close range over 2 times as many decibels than a normal conversation.

The above answer is FALSE:

The decibel scale is logarithmic and thus a 140 dB sound would be 10^14 above 0 decibel; the 60 dB sound would be 10^6 above 0 decibel. Thus the close range jet is around 10^(14 - 6) = 10^8, or 100,000,000 times the loudness of a normal conversation.