What is sound?
Sound is a vibration or a wave of air molecules which is caused by the motion of an object. The density of the molecules is higher when there is a compression wave. This compression wave travels through the air at the speed depending on the temperature of the surroundings. Since a sound wave contain energy which means it can make things move. But, if the sound wave hits something solid, the wave will bounce back forming an echo. Sound cannot travel through a vacuum. It can only travel through solids, liquids, gases and plasmas.
How is sound being produced?
Sound waves
A series of compressions and rarefactions which changes or waves through the air is called a sound wave. Sound waves vibrate at different rates or frequencies as they move through the air. Frequency is measured in cycles per second, or Hertz (Hz). The faster an object vibrates the higher the pitch of the sound. A frequency of 100 Hz means 100 vibrations every second.
Echolocation
The sound which travels to the walls and is reflected back to our ears is called an echo. Echoes are used to find objects underwater, to find large shoals of fish and to measure the depth of the sea. Animals use echoes to find food and to ‘see’ where they are going. For example, bats. They have a poor sense of sight but a good sense of hearing. They use echolocation to find food. Bats produce a high frequency sound to find insects to eat. This sound then reflects off the insect and travel back to the bat’s ears. This helps the bat to find even the smallest insect. Echolocation also helps the bat to ‘see’ where it is flying.
What affects sound?
Sound vibration
When an object moves or vibrates, sound is produced. There could be no sound without movement. When an object moves or vibrates, the air molecules around it will also vibrate. As long as they are not in a vacuum, vibrating objects produce sound. Each molecule moves back and forwards only in a tiny distance which is enough to cause the air particles to bump into each other. This will create areas where there are many molecules pushed closer. This is called compression. Areas where molecules are spread far apart are called rarefactions. Compressions and rarefactions move outwards away from the sound source in circles.
The speed of sound
Sound will take time to travel. In air, sound travels at a speed of 330 metres per second. In fresh water, sound travels at a speed of 150 metres per second. Sound travels at even higher speeds in solids. For example, an iron sound travels at 5000 metres per second. So, the speed of sound depends on density. The denser the material is the faster the speed of sound.
Examples of stuff producing sound
Here are some examples of things that produce sound:
-A guitar
-A trumpet
-A drum
-A bee (buzzing sound caused by its wings)
-A recorder
-Cars
-Airplanes
And many more.
Sources
http://www.sciencetech.technomuses.ca/english/schoolzone/Info_Sound.cfm
Explore your world with Science discovery 2 (pages 202-206)
http://en.wikipedia.org/wiki/Sound
Showing posts with label sound. Show all posts
Showing posts with label sound. Show all posts
Friday, June 20, 2008
Sound by 2E1 Ebel
SOUND
[A]Sound is a form of energy and is caused by objects vibrating .
[B]Sound travels through air as vibrations .When a loudspeaker produce a sound , the vibration of the skin of the speaker causes the surrounding air molecules to also vibrate . These vibration spread outwards , passing on the sound energy until it reaches the ears.
[C]Sound takes time to travel from one place to the other. Sound travels at a speed of 330m/s in air .This is much slower than the speed of light [300 000 000m/s]Thats why you will always see the flash of lighting followed by the crack of thunder .
[D]Sound cannot travel through a vacuum[empty space] it needs a medium[substance] to travel through .Sound can travel through gases , liquid and solids. It travels through liquid and solids faster than gases as the particles of solid and liquids are closer , so the vibration pass more easily .However , the energy of the sound is soon used up passing through liquids and solids .
[E]Sound are all around us and provide a means of communication [talking , whistling and singing ] give us warning signals [alarms , telephones , fire bells , police sirens] give us pleasure [music , singing ]
[F]However some sound are unnecessary , they are describes as noise [ traffic noise , loud music , aircraft noise , building sites noise , drilling noise ]. Sound levels are measured as decibels[dB].The loudest sound , which causes pain is called the threshold of pain.
[G]The ear is the natural detector of sound . The external ear is like a funnel to channel the sound waves towards the ear drum .This then starts to vibrate and the bones in the middle ear amplify this vibration which causes waves in the liquid inside the inner ear. These waves produce electrical pulses in the nerve cells which are carried by the auditory nerve to the brain intercepts these electrical signs as sounds
Biobliography:Science Keynotes -Christopher N. Prescott
[A]Sound is a form of energy and is caused by objects vibrating .
[B]Sound travels through air as vibrations .When a loudspeaker produce a sound , the vibration of the skin of the speaker causes the surrounding air molecules to also vibrate . These vibration spread outwards , passing on the sound energy until it reaches the ears.
[C]Sound takes time to travel from one place to the other. Sound travels at a speed of 330m/s in air .This is much slower than the speed of light [300 000 000m/s]Thats why you will always see the flash of lighting followed by the crack of thunder .
[D]Sound cannot travel through a vacuum[empty space] it needs a medium[substance] to travel through .Sound can travel through gases , liquid and solids. It travels through liquid and solids faster than gases as the particles of solid and liquids are closer , so the vibration pass more easily .However , the energy of the sound is soon used up passing through liquids and solids .
[E]Sound are all around us and provide a means of communication [talking , whistling and singing ] give us warning signals [alarms , telephones , fire bells , police sirens] give us pleasure [music , singing ]
[F]However some sound are unnecessary , they are describes as noise [ traffic noise , loud music , aircraft noise , building sites noise , drilling noise ]. Sound levels are measured as decibels[dB].The loudest sound , which causes pain is called the threshold of pain.
[G]The ear is the natural detector of sound . The external ear is like a funnel to channel the sound waves towards the ear drum .This then starts to vibrate and the bones in the middle ear amplify this vibration which causes waves in the liquid inside the inner ear. These waves produce electrical pulses in the nerve cells which are carried by the auditory nerve to the brain intercepts these electrical signs as sounds
Biobliography:Science Keynotes -Christopher N. Prescott
Sound by 2E4 Luan Niannian
What is sound?
Soundis a from of energy.It is caused by vibrations.Sound is the quickly varying pressure wave within a medium. We usually mean audible sound, which is the sensation (as detected by the ear) of very small rapid changes in the air pressure above and below a static value. This "static" value is atmospheric pressure (about 100,000 Pascals) which does nevertheless vary slowly, as shown on a barometer. Associated with the sound pressure wave is a flow of energy.
Sound is often represented diagrammatically as a sine wave, but physically sound (in air) is a longitudinal wave where the wave motion is in the direction of the movement of energy. The wave crests can be considered as the pressure maxima whilst the troughs represent the pressure minima.
How small and rapid are the changes of air pressure which cause sound?
When the rapid variations in pressure occur between about 20 and 20,000 times per second (i.e. at a frequency between 20Hz and 20kHz) sound is potentially audible even though the pressure variation can sometimes be as low as only a few tens of millionths of a Pascal. Movements of the ear drum as small as the diameter of a hydrogen atom can be audible!
Louder sounds are caused by greater variation in pressure. A sound wave of one Pascal amplitude, for example, will sound quite loud, provided that most of the acoustic energy is in the mid-frequencies (1kHz - 4kHz) where the human ear is most sensitive. It is commonly accepted that the threshold of human hearing for a 1 kHz sound wave is about 20 micro-Pascals.
What makes sound?
Sound is produced when the air is disturbed in some way, for example by a vibrating object. A speaker cone from a high fidelity system serves as a good illustration. It may be possible to see the movement of a bass speaker cone, providing it is producing very low frequency sound. As the cone moves forward the air immediately in front is compressed causing a slight increase in air pressure, it then moves back past its rest position and causes a reduction in the air pressure (rarefaction). The process continues so that a wave of alternating high and low pressure is radiated away from the speaker cone at the speed of sound.
What affects sound?
Sound can travel through solids,liquids and gases.Sound cannot travel through vacuum because it requires a medium to travel. Voices in different substances in different speed. The speed of sound effects spread to two factors: media and wave source The surrounding temperature changes, the density of the air has changed (the higher the temperature, density greater, because the higher the temperature, air Lengsu heat up, so will have partial pressure increases, that is, increasing density) is the medium change The The voice of the spread of medium density greater voice transmission of the greater speed That is, the higher the temperature in the voice of the environment in the faster spread
What is a decibel (dB)?
The decibel is a logarithmic unit which is used in a number of scientific disciplines. Other examples are the Richter scale for earthquake event energy and pH for hydrogen ion concentration in liquids.
In all cases the logarithmic measure is used to compare the quantity of interest with a reference value, often the smallest likely value of the quantity. Sometimes it can be an approximate average value.
In acoustics the decibel is most often used to compare sound pressure, in air, with a reference pressure. References for sound intensity, sound power and sound pressure in water are amongst others which are also commonly in use.
How is sound measured?
A sound level meter is the principal instrument for general noise measurement. The indication on a sound level meter (aside from weighting considerations) indicates the sound pressure, p, as a level referenced to 0.00002 Pa, calibrated on a decibel scale.
http://www.tek-ltd.com/school2.htm
Soundis a from of energy.It is caused by vibrations.Sound is the quickly varying pressure wave within a medium. We usually mean audible sound, which is the sensation (as detected by the ear) of very small rapid changes in the air pressure above and below a static value. This "static" value is atmospheric pressure (about 100,000 Pascals) which does nevertheless vary slowly, as shown on a barometer. Associated with the sound pressure wave is a flow of energy.
Sound is often represented diagrammatically as a sine wave, but physically sound (in air) is a longitudinal wave where the wave motion is in the direction of the movement of energy. The wave crests can be considered as the pressure maxima whilst the troughs represent the pressure minima.
How small and rapid are the changes of air pressure which cause sound?
When the rapid variations in pressure occur between about 20 and 20,000 times per second (i.e. at a frequency between 20Hz and 20kHz) sound is potentially audible even though the pressure variation can sometimes be as low as only a few tens of millionths of a Pascal. Movements of the ear drum as small as the diameter of a hydrogen atom can be audible!
Louder sounds are caused by greater variation in pressure. A sound wave of one Pascal amplitude, for example, will sound quite loud, provided that most of the acoustic energy is in the mid-frequencies (1kHz - 4kHz) where the human ear is most sensitive. It is commonly accepted that the threshold of human hearing for a 1 kHz sound wave is about 20 micro-Pascals.
What makes sound?
Sound is produced when the air is disturbed in some way, for example by a vibrating object. A speaker cone from a high fidelity system serves as a good illustration. It may be possible to see the movement of a bass speaker cone, providing it is producing very low frequency sound. As the cone moves forward the air immediately in front is compressed causing a slight increase in air pressure, it then moves back past its rest position and causes a reduction in the air pressure (rarefaction). The process continues so that a wave of alternating high and low pressure is radiated away from the speaker cone at the speed of sound.
What affects sound?
Sound can travel through solids,liquids and gases.Sound cannot travel through vacuum because it requires a medium to travel. Voices in different substances in different speed. The speed of sound effects spread to two factors: media and wave source The surrounding temperature changes, the density of the air has changed (the higher the temperature, density greater, because the higher the temperature, air Lengsu heat up, so will have partial pressure increases, that is, increasing density) is the medium change The The voice of the spread of medium density greater voice transmission of the greater speed That is, the higher the temperature in the voice of the environment in the faster spread
What is a decibel (dB)?
The decibel is a logarithmic unit which is used in a number of scientific disciplines. Other examples are the Richter scale for earthquake event energy and pH for hydrogen ion concentration in liquids.
In all cases the logarithmic measure is used to compare the quantity of interest with a reference value, often the smallest likely value of the quantity. Sometimes it can be an approximate average value.
In acoustics the decibel is most often used to compare sound pressure, in air, with a reference pressure. References for sound intensity, sound power and sound pressure in water are amongst others which are also commonly in use.
How is sound measured?
A sound level meter is the principal instrument for general noise measurement. The indication on a sound level meter (aside from weighting considerations) indicates the sound pressure, p, as a level referenced to 0.00002 Pa, calibrated on a decibel scale.
http://www.tek-ltd.com/school2.htm
Sound by 2E1 Tan Hui Yu
What is sound?
Sound is a mechanical wave which results from the back and forth vibration of the particles of the medium through which the sound wave is moving. If a sound wave is moving from left to right through air, then particles of air will be displaced both rightward and leftward as the energy of the sound wave passes through it. The motions of the particles are parallel (and anti-parallel) to the direction of the energy transport. This is what characterizes sound waves in air as longitudinal waves.
How is sound being produced?
Sound are produced by the vibration of object . Sound is a physical entity, unlike noise which is the perception of sound. Sound is an high pressure wave front through a medium (such as air, or a liquid such as water, or a solid), wherein the wave front is followed by a reciprocal pressure differential behind it. Sound is produced when something disturbs the medium and sets in motion the molecules in the medium.
What affects sound?
One thing that can propagate sound is if you were to place something of which emits sound in a vacuum. The sound waves will propagate in the vacuum, because the matter which supports the sound called the medium no longer exists.
Source, http://en.wikipedia.org/wiki/Sound
Examples of stuff producing sound .
There are many things that can produce sound
Examples are radios , television , printers , fans .
What did I learn about the particular topic ?
I learn that sound is part of our life as it is everywhere . When we cough , a sound is made . When we talk or laugh with our friends , a sound is made . So it is very common to have sound everywhere .
Key points of the topic
Sound is a form of energy .
Are produced by the vibration of objects .
Sound travels through matter-solids, liquids and gases . Sound cannot travel through a vacuum .
Sources : Textbook resource , Source, http://en.wikipedia.org/wiki/Sound
Sound is a mechanical wave which results from the back and forth vibration of the particles of the medium through which the sound wave is moving. If a sound wave is moving from left to right through air, then particles of air will be displaced both rightward and leftward as the energy of the sound wave passes through it. The motions of the particles are parallel (and anti-parallel) to the direction of the energy transport. This is what characterizes sound waves in air as longitudinal waves.
How is sound being produced?
Sound are produced by the vibration of object . Sound is a physical entity, unlike noise which is the perception of sound. Sound is an high pressure wave front through a medium (such as air, or a liquid such as water, or a solid), wherein the wave front is followed by a reciprocal pressure differential behind it. Sound is produced when something disturbs the medium and sets in motion the molecules in the medium.
What affects sound?
One thing that can propagate sound is if you were to place something of which emits sound in a vacuum. The sound waves will propagate in the vacuum, because the matter which supports the sound called the medium no longer exists.
Source, http://en.wikipedia.org/wiki/Sound
Examples of stuff producing sound .
There are many things that can produce sound
Examples are radios , television , printers , fans .
What did I learn about the particular topic ?
I learn that sound is part of our life as it is everywhere . When we cough , a sound is made . When we talk or laugh with our friends , a sound is made . So it is very common to have sound everywhere .
Key points of the topic
Sound is a form of energy .
Are produced by the vibration of objects .
Sound travels through matter-solids, liquids and gases . Sound cannot travel through a vacuum .
Sources : Textbook resource , Source, http://en.wikipedia.org/wiki/Sound
Sound by 2E1 Desiree Ang
What is sound?
CRASH BANG! Did you hear that sound? This is called sound and you hear sound everyday. Sound is a form of energy and they are produced by the vibration of objects and the number to count vibration/sec is frequency. Frequency is measured in hertz (Hz).
CRASH BANG! Did you hear that sound? This is called sound and you hear sound everyday. Sound is a form of energy and they are produced by the vibration of objects and the number to count vibration/sec is frequency. Frequency is measured in hertz (Hz).
Transmission of sound.
Sound travels through solid, liquids and gases in 330m/s from one place to another. However, sound cannot travel through a vacuum. Sound travels in a form of waves.
Sound travels through solid, liquids and gases in 330m/s from one place to another. However, sound cannot travel through a vacuum. Sound travels in a form of waves.
Pitch and music.
A musical note is called a tone which is produced by air vibrating a certain number of times per second. Some instruments have a string, reed or some other devices to create sound waves when moved. A high pitch has high frequency while a low pitch has low frequency. For wind instruments, the shorter the column of air, the higher the pitch of a note.
Natural sound producer.
Our vocal cords are our natural sound producer.
The human ear.
It is a sound detector and it has 3 main parts. The outer ear, middle ear and inner ear. The human ear can only hear a limited range of sound frequencies.
It is a sound detector and it has 3 main parts. The outer ear, middle ear and inner ear. The human ear can only hear a limited range of sound frequencies.
The importance of sound
Sound is a form of communication and warning signal. So it is important. However, noise that is loud, is unpleasant. Sounds above 90dB can cause damage to our ears and if you want to reduce noise level, ear protectors are used. Sound frequencies that are higher than those detected by humans, are used as ultrasound used in the medicinal industry.
A world without sound can cause one to be lonely and lost. Hence, sound is important!
Sound is a form of communication and warning signal. So it is important. However, noise that is loud, is unpleasant. Sounds above 90dB can cause damage to our ears and if you want to reduce noise level, ear protectors are used. Sound frequencies that are higher than those detected by humans, are used as ultrasound used in the medicinal industry.
A world without sound can cause one to be lonely and lost. Hence, sound is important!
Credits`: http://library.thinkquest.org/5116/sound.htm and science discovery 2 (textbook)
Thursday, June 19, 2008
Sound by 2E2 Syafiqah
I've learnt something about sound from the sources i had taken and studied,such as borrow books at the library, looking at the science textbook and also searching information on the internet. What i've learnt? I've learnt that sound is a type of energy that were produced when an object vibrates.
Why do we hear sounds?
Humans have three parts, the outer ear, the middle ear and the inner ear.
What does the outer ear do? It collects and funnels the sound to the middle ear. Between the outer ear and the middles ear is a membrane called the eardrum.
What cause the eardrum vibrate?
Sound waves cause the eardrum to vibrate. When the eardrum vibrates, it touches the first of the three tiny bones in the middle ear. This bone vibrates and cause the other two bones to vibrate.
( source taken by book physical science in depth and http://www.worsleyschool.net/science/files/sound/energy.html )
Why do we hear sounds?
Humans have three parts, the outer ear, the middle ear and the inner ear.
What does the outer ear do? It collects and funnels the sound to the middle ear. Between the outer ear and the middles ear is a membrane called the eardrum.
What cause the eardrum vibrate?
Sound waves cause the eardrum to vibrate. When the eardrum vibrates, it touches the first of the three tiny bones in the middle ear. This bone vibrates and cause the other two bones to vibrate.
( source taken by book physical science in depth and http://www.worsleyschool.net/science/files/sound/energy.html )
Sound by 2E2 Rosalind
I learnt What is Sound and What are Sound Waves.
Sound is a type of energy. It is a vibration that travels through the surroundings and enters our ears as sound .
Sound waves are waves which radiate out from their source in circles. The particles of air in the wave move backward and forwards in the same direction as the sound is travelling. These bands of compression and rarefaction move along the spring. This is how s sound wave moves through air, water or solid materials.
Sounds needs to travel through a medium, such as a gas, a liquid or a solid. It cannot travel through a vacuum. This is because sound is a form of energy. In order for sound to move it has to tranfer its energy from one particle to another. If there are no particles, sound cannot travel.
Sound waves are invisible to us, but they can be represented by a machine called an Oscilloscope.
(source taken from book: physical sound IN DEPTH, SOUND)
Sound is a type of energy. It is a vibration that travels through the surroundings and enters our ears as sound .
Sound waves are waves which radiate out from their source in circles. The particles of air in the wave move backward and forwards in the same direction as the sound is travelling. These bands of compression and rarefaction move along the spring. This is how s sound wave moves through air, water or solid materials.
Sounds needs to travel through a medium, such as a gas, a liquid or a solid. It cannot travel through a vacuum. This is because sound is a form of energy. In order for sound to move it has to tranfer its energy from one particle to another. If there are no particles, sound cannot travel.
Sound waves are invisible to us, but they can be represented by a machine called an Oscilloscope.
(source taken from book: physical sound IN DEPTH, SOUND)
Sound by 2E2 Shayidah
I have learnt that Sound is a vibration.
When something makes a noise it is vibrating,and this causes air molecules around it to vibrate too.
These vibrations are transmitted through the air, to our ears, where we preceive them as sound.
Do you know that Thunder is one of nature's loudest sounds!
A nearby thunderclap may reach 120 decibals,equiralent to being within 60 metres of a jet aircraft during take-off.
Volcano eruptions may be the loudest commonly occuring Sounds on Earth,at over 272 dB.
When something makes a noise it is vibrating,and this causes air molecules around it to vibrate too.
These vibrations are transmitted through the air, to our ears, where we preceive them as sound.
Do you know that Thunder is one of nature's loudest sounds!
A nearby thunderclap may reach 120 decibals,equiralent to being within 60 metres of a jet aircraft during take-off.
Volcano eruptions may be the loudest commonly occuring Sounds on Earth,at over 272 dB.
Sound by 2E2 Diyana
We did on the topic 'Sounds'.I learnt the particular topic in our school science textbook and borrowed some books from the library.I also did some research in the internet about sounds.
Sound is made when something vibrates, it moves back and forth.A vibrating object could be a speaker on a CD player, or your vocal cords or even the strings on a guitar.
As it vibrates, it pushes the air molecules next to it closer together, in patterns corresponding to the movements of the object.
Sound can also be used to do useful jobs. For example; Sound waves sent into the womb of a pegnant woman will be deflected in patterns representing the outline of the fetus within.
(Source taken from www.yahoo.com)
Sound by 2E1 Priscilla Gwee
Sound is a form of energy. Sound is the quickly varying pressure wave within a medium.
Sound is produced by the vibration of objects. When object vibrate, they move backwards and forwards very quickly. Frequency is the number of vibrations in one second. Frequency is measured in hertz (Hz).If the frequency is 100Hz, it means that it produced 100 vibrations every seconds.
The medium affect the speed of sound. Thus it will also affect the sound.
The examples of stuff producing sound are instruments, insects, phones, human talking, music from CD player, sound of the fan, traffic noise and alarm clock.
Sound travels in the form of waves. Sound travels through matter (solids, liquids and gases). Sound toke time to travel from one place to another. The speed of the sound in the air is about 330 metres per seconds.
We can also find things with sound. For example, if we make a loud noise in a large room, there will be echo. The sound we make travels to the walls and is reflected back to our ears. Echoes are also able to find objects underwater. This is called echolocation.
Some uses of echolocation is to find submarines from surface ships, to measure the depth of the sea and to find shoals of fish in fishing boats. Animals like bats and dolphins also use echolocation to find food and where they are going.
Websites: www.yahoo.com
www.google.com
www.ask.com
Textbook Resource: Explore Your World With Science Discovery 2.
Sound is produced by the vibration of objects. When object vibrate, they move backwards and forwards very quickly. Frequency is the number of vibrations in one second. Frequency is measured in hertz (Hz).If the frequency is 100Hz, it means that it produced 100 vibrations every seconds.
The medium affect the speed of sound. Thus it will also affect the sound.
The examples of stuff producing sound are instruments, insects, phones, human talking, music from CD player, sound of the fan, traffic noise and alarm clock.
Sound travels in the form of waves. Sound travels through matter (solids, liquids and gases). Sound toke time to travel from one place to another. The speed of the sound in the air is about 330 metres per seconds.
We can also find things with sound. For example, if we make a loud noise in a large room, there will be echo. The sound we make travels to the walls and is reflected back to our ears. Echoes are also able to find objects underwater. This is called echolocation.
Some uses of echolocation is to find submarines from surface ships, to measure the depth of the sea and to find shoals of fish in fishing boats. Animals like bats and dolphins also use echolocation to find food and where they are going.
Websites: www.yahoo.com
www.google.com
www.ask.com
Textbook Resource: Explore Your World With Science Discovery 2.
Sound by 2E1 Aziizah
What is sound?
Sound is the quickly varying pressure wave within a medium. We usually mean audible sound, which is the sensation (as detected by the ear) of very small rapid changes in the air pressure above and below a static value. This "static" value is atmospheric pressure (about 100,000 Pascals), which does nevertheless vary slowly, as shown on a barometer. Associated with the sound pressure wave is a flow of energy. Sound is often represented diagrammatically as a sine wave, but physically sound (in air) is a longitudinal wave where the wave motion is in the direction of the movement of energy. The wave crests can be considered as the pressure maxima whilst the troughs represent the pressure minima.
ii. How is sound being produced?
Sound is produced when the air is disturbed in some way, for example by a vibrating object. A speaker cone from a high fidelity system serves as a good illustration. It may be possible to see the movement of a bass speaker cone, providing it is producing very low frequency sound. As the cone moves forward the air immediately in front is compressed causing a slight increase in air pressure, it then moves back past its rest position and causes a reduction in the air pressure (rarefaction). The process continues so that a wave of alternating high and low pressure is radiated away from the speaker cone at the speed of sound.
iii. What affects sound?
Vibrations and frequency affects sound. Vibrations produce sounds. When objects vibrate, they move backwards and forwards very quickly. The number of vibrations in one second is called the frequency.
iv. Examples of stuff producing sound?
Drums
Guitar
Bee
Trumpet
Saxophone
Summary:
Sound is a form of energy.
The vibration of objects produces sounds.
Frequency is the number of vibrations per second. Frequency is measured in hertz {Hz).
Sources:
http://www.tek-ltd.com/school2.htm
Sound is the quickly varying pressure wave within a medium. We usually mean audible sound, which is the sensation (as detected by the ear) of very small rapid changes in the air pressure above and below a static value. This "static" value is atmospheric pressure (about 100,000 Pascals), which does nevertheless vary slowly, as shown on a barometer. Associated with the sound pressure wave is a flow of energy. Sound is often represented diagrammatically as a sine wave, but physically sound (in air) is a longitudinal wave where the wave motion is in the direction of the movement of energy. The wave crests can be considered as the pressure maxima whilst the troughs represent the pressure minima.
ii. How is sound being produced?
Sound is produced when the air is disturbed in some way, for example by a vibrating object. A speaker cone from a high fidelity system serves as a good illustration. It may be possible to see the movement of a bass speaker cone, providing it is producing very low frequency sound. As the cone moves forward the air immediately in front is compressed causing a slight increase in air pressure, it then moves back past its rest position and causes a reduction in the air pressure (rarefaction). The process continues so that a wave of alternating high and low pressure is radiated away from the speaker cone at the speed of sound.
iii. What affects sound?
Vibrations and frequency affects sound. Vibrations produce sounds. When objects vibrate, they move backwards and forwards very quickly. The number of vibrations in one second is called the frequency.
iv. Examples of stuff producing sound?
Drums
Guitar
Bee
Trumpet
Saxophone
Summary:
Sound is a form of energy.
The vibration of objects produces sounds.
Frequency is the number of vibrations per second. Frequency is measured in hertz {Hz).
Sources:
http://www.tek-ltd.com/school2.htm
Sound by 2E1 Ng Xinying
In this topic I've learnt about what causes sound, the transmisson of sound,more things about the human
ears, the pitch and music and the importance of soun in the society.
Now im going to summarise what i have learnt about the topic.
I have learnt that....
Sound is a form of energy.
Sounds are produced by the vibration of objects.
Frenquency is the number of vibrations per sec. And they are measured in Hertz(Hz)
Sound travels through matter -Liquid,Solid and Gas.
Sound takes time to travel from one place to another. the speed of sound in the air is about 330 metres per second.
Sound travels in form of waves.
The human ear can hear only a limited range of sound frequencies.
The ear is a sound detector that has 3 main parts, the outer ear,the inner ear and the middle ear.
Sound is important in society for communication as a warning and as a pleasure.
Noise is sound that is loud and unpleasant.
the loudness of sound is measured as decibels(dB).
Sound above 90dB can cause damage to our ears.
Ear protectors and noise barriers are two ways of reducing loud noise.
Sound frequencies higher than those that can be detected by humans are called ultrasound.
Ultrasound has many application in industry and medicine.
the higness and lowness of a musical note is called its pitch.
a note with a low pitch is called a low frenquency. A note with a high pitch is called a high frequency.
For wind instruments,the shorter the column of air, the higher the pitch of a note.
For string instruments,the shorter the string the higher pitch of a note.
The vocal cords in our throats produce sounds.
Here's a fact!
Have you experienced a ringing sound in your ears after listening to loud music or noise? People who are continually exposed to loud sounds develop a permanent ringing sound. this affliction ehich cannot be cured is called tinitus.
ears, the pitch and music and the importance of soun in the society.
Now im going to summarise what i have learnt about the topic.
I have learnt that....
Sound is a form of energy.
Sounds are produced by the vibration of objects.
Frenquency is the number of vibrations per sec. And they are measured in Hertz(Hz)
Sound travels through matter -Liquid,Solid and Gas.
Sound takes time to travel from one place to another. the speed of sound in the air is about 330 metres per second.
Sound travels in form of waves.
The human ear can hear only a limited range of sound frequencies.
The ear is a sound detector that has 3 main parts, the outer ear,the inner ear and the middle ear.
Sound is important in society for communication as a warning and as a pleasure.
Noise is sound that is loud and unpleasant.
the loudness of sound is measured as decibels(dB).
Sound above 90dB can cause damage to our ears.
Ear protectors and noise barriers are two ways of reducing loud noise.
Sound frequencies higher than those that can be detected by humans are called ultrasound.
Ultrasound has many application in industry and medicine.
the higness and lowness of a musical note is called its pitch.
a note with a low pitch is called a low frenquency. A note with a high pitch is called a high frequency.
For wind instruments,the shorter the column of air, the higher the pitch of a note.
For string instruments,the shorter the string the higher pitch of a note.
The vocal cords in our throats produce sounds.
Here's a fact!
Have you experienced a ringing sound in your ears after listening to loud music or noise? People who are continually exposed to loud sounds develop a permanent ringing sound. this affliction ehich cannot be cured is called tinitus.
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