What is sound and how do we

hear it? How are sounds made?How does sound get from the source to your ears?

Sound is a type of energy made by vibrations. When any object vibrates, it causes movement in the air particles. These particles bump into the particles close to them, which makes them vibrate too causing them to bump into more air particles. This movement, called sound waves, keeps going until they run out of energy. If your ear is within range of the vibrations, you hear the sound.http://www.sciencekidsathome.com/science_topics/what_is_sound.html

What is sound? Watch this movie to find out!

Click this link if video does not play

The main points from the movie were:

- When sounds travel we are actually hearing how the vibrations affectthe air molecules

- Molecules squeezing and stretching through the air are what we call sound waves.

- Sound travels slower than light. That is why we see lightening before we hearThunder in a storm.

-Air molecules in a long tube vibrate more slowly, producing a lower pitch.Air molecules in a short tube vibrate more quickly, producing a higher pitch.

-Pitch is measured by the number of vibrations per second. The faster the vibrations,the higher the pitch.

• Sound waves travel through the air and enter the ear causing the ear drum to vibrate.

• The vibrations are processed in the ear in the cochlear, which sends messages to our brain, and our brain interprets these as sound.

• If sound intensity is too great, or happens for a long period of time, the cells will dieat the beginning of the cochlear.

• High frequency sounds are heard by the beginning of the cochlear, and low Frequency sounds are heard by the end of the cochlear.

• This is why many older people cannot hear high frequency sounds as well.

Just like Mr Murphy!

• Sound is measured in decibels. A quiet library is about 40 decibels, while a loudrock band would be about 150 decibels.

I can’t stand loud

music!!

How do we hear sounds?

1. Ear canal2. ear drum3. Hammer4. anvil5. Stirrup8. Cochlea (inner ear)9. The nerve of hearing

Sound wavesEnter the earcanal

The ear drum vibrates and then the hammer, anvil and stirrup vibrate sending the vibrations to the cochlea (inner ear).

The little hairs in the cochlea move and they change the vibrations into a signal. This signal is then sent to the brain through the nerve of hearing like a message. The brain interprets this message for us – and that is how we hear!

http://www.oticonchildren.com/children/com/Otikids/AboutHearing/HowDoesTheEarWork/index

Protect your hearing Don’t listen to very loud sounds for

long periods of time.The most significant

singlecause of hearing loss inAustralia is exposure to

loud noise. 37% of hearing

loss is due to excessivenoise exposure.

http://www.hearing.com.au/upload/media-room/Hearing-loss-in-Australia.pdf

A hearing loss can result ifthere’s a problem at any pointin the hearing pathway –in the outer, middle or innerears, or in the complex auditorynerve pathway to the brain.

What else causes hearing loss?

Hearing loss can be:- present when you are born- Acquired later, through illness , accident, exposure to chemicals or drugs- Caused by a blockage or damage to theInner or outer ear, cochlea or auditory (Hearing nerve)

Click here for more information on hearing loss in Australia

http://www.australiandoctor.com.au

Click here for more info on frequency and intensity of familiar sounds.

Soundwaves

See soundwaves in action!

One in six people in Australia has a hearning loss. With the ageing of the Australian population, hearing loss is projected to increase to one in four Australians by 2050.

http://suddenhearingloss.net/hearing-loss-symptoms/

Let’s make some sound with :

- A plastic cup

- A paperclip

- Some wool

- Some damp paper towel

Can you make theSound of a farmyard animal usingthese things????

Click here for the link to the experiment

How does it work?The cup and string demonstration is is an example of how a sounding board works. The vibrations from the string would be almost silent without the cup, but when you add the cup, it spreads the vibrations and amplifies them (makes them louder.) Pianos and music boxes use wood to act as a sounding board to make the instrument louder.

5. Why does a flute have a higher pitch than a bass clarinet?

Task:Write down the answers to the following questions.

1. If someone asked you “What is sound?” how would you explain it?

2. In a thunderstorm, why do we see lightening before we hear thunder?

3.What is the unit of measurement for sound?

4. James listens to his ipod on full volume every day. How will this damage his hearing?

6. What are some causes of hearing loss?

A bone conductor is a hearing aid

that allows you to hear without

soundgoing through

your eardrums.

http://www.audioboneheadphones.com/howitworks.html

How It Works

Invented by Beethoven – Perfected by Audio Bone How It Works

It is how we normally hearWe all hear sounds through both our bones and our ear drums. Most sounds are heard by our ear drums.The ear drum converts the sound waves to vibrations and transmits them to the cochlea(or inner ear). But in some cases vibrations are heard directly by the inner ear – bypassing your ear drums. In fact, this is one of the ways you hear your own voice. This is also how whales hear.

Invented by BeethovenBone conduction was discovered by Ludwig van Beethoven, the famous 18th century composer who was almost deaf. Beethoven found a way to hear music through his jawbone by biting a rod attached to his piano.

Ludwig Van Beethoven 1770-1827

Click here for more information about bone conductor hearing aids