The Science of Music

22nd October 2012

On today’s show we will be talking about music and how science can actually enhance the listening experience! We also have arranged for a very special guest – Science Show elf Ben! Ben will be playing his guitar to help demonstrate what we will be talking about.

Sheet music

If anyone can work out what piece of music that is above, you get the love and admiration of Carl. Not that it’s worth much 😉

Part One – A Journey Into Sound

We’ll be talking about how sound is produced and how the ear works. Tune in to find out more!

Sound, as you probably know, is a wave! However it needs something, or a medium to travel through. This is why there’s no sound in space. Sound travels at 340.29 meters per second in air.

So how does the ear work?
The Ear

Sounds from the outside world are picked up by the outer ear, the sound wave is directed down the ear canal towards the ear drum. The sound vibrations continue their journey into the middle ear, which contains three tiny bones which bridge from the outer ear to the inner ear. The inner ear is shaped like a snails shell which contains fluid. The vibrations are then converted into electrical signals which are sent to the brain.

Resonance

The definition of resonance that “resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others.” Basically all that means is if you input the right amplitude to a system it will vibrate to greater and greater amounts.

Perhaps the most well-known example of this is the opera singer and a wine glass. If the singer sings the right note it will cause the glass to vibrate and eventually enough energy will be input to cause it to shatter.

Alternatively, the Tacoma Narrows Bridge is also well known, it eventually shook itself to destruction. A video can be found here: http://en.wikipedia.org/wiki/File:Tacoma_Narrows_Bridge_destruction.ogg

Part Two – The Maths of Music

Consider the note called “Middle C” (usually the first note learned in piano lessons). This note has a frequency of about 262 Hertz. That means that when Middle C is played, 262 pockets of higher air pressure pound against your ear each second.

Equivalently, the pockets of air arrive so quickly that one pocket strikes your ear every 0.00382 seconds. A basic rule is that higher-pitched notes have a higher frequency, corresponding to more frequent air pocket arrivals.

Middle C and High C

Since the frequency of High C is exactly twice that of Middle C, the two notes line up perfectly. Every two air pocket arrivals for High C correspond perfectly to one arrival for Middle C. This is why notes an octave apart sound good played together.

If I’m honest, it’s hard for me to show on the blog what Ben is playing in the studio, I’d check out the podcast! I’ll post the link here once we’ve uploaded it. Magic.

Here’s the interview we sent Jenna off to get, she spoke to Dr. Brian Gygi about the decibel system and pleasant and unpleasant sounds.

Part Three – The Psychology of Noise

So we’re now talking about odd noises, there are some pretty odd ones out there such as brown noise, horrible ones such as nails on a chalkboard, we’ll add the noises to the blog after the show, or check out the podcast guys!