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Sensing vibration

If you are standing somewhere between the car and the point at which the vibrations are no longer significant, the air molecules in your ear canals willbegin to vibrate. This will stimulate nerves that lead from your ear to your brain. Your brain will interpret the stimulation as something that we refer to sound .

Therefore, when the tree falls, it causes the air molecules to vibrate. However, if there are no ear canals around, no nerves to be stimulated, and no brain to interpretthat stimulation, there is no sound.

Creating sound with a hammer

All we need to do to cause a person to experience sound is to cause the air molecules in that person's ear canals to vibrate at afrequency somewhere between 20 Hz (cycles per second) and 20,000 Hz, depending on the person's age. Usually as a person ages, the range defined bythose upper and lower limits decreases. Thus, a young person may "hear" the high-pitched whine of a power saw while an older person may not experience soundin that situation.

There are many ways that we can cause most humans to experience sound. One way for example, is to strike a bell with a hammer. Another way is to write aprogram to cause the diaphragm of a computer speaker to vibrate. That will be the topic of the next few modules in this course.

Creating sound with a computer

One way to create sound with a computer would be to hold it out and drop it on the floor. However, that is not what we intend to do. Instead, we intend towrite computer program that will cause the computer to create sound.

An object of a class

As you will learn in a future module, we can define a class and instantiate an object of that class for use in producing sound with a computer. When usedproperly in a program, that object will cause signed numeric values stored in an array to be converted to electrical current in the speakers attached to the computer.Positive values will cause the current to flow in one direction and negative values will cause the current to flow in the opposite direction.

Alternating positive and negative values

If we populate that array with alternating groups of positive and negative values, that will cause the current being delivered to the speakers toalternate, switching from one direction to the other. The level of the alternating currents will be roughly proportional to the magnitudes of thealternating positive and negative values. Given sufficient magnitude within a frequency range supported by the speakers, the alternating currents will causethe diaphragms of the speakers to vibrate or move back and forth. This, in turn, will cause the adjacent air molecules to vibrate, which may be sensed as soundby a person within hearing distance of the speakers.

Sine and cosine functions

Populating the array

There are many ways that we can write a program to populate the array with alternating groups of positive and negative numbers. One of the simplest ways is topopulate the array with scaled versions of the values produced by the static sin function or the static cos function of the Math class. The Math class is contained in the Java Standard Edition class library. A common name for a series of such values is sinusoid .

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
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