Propagation of Sound

Sound Propagation

Hi! This is Cris. I'm posting this assignment as part of the course in "Introduction to Music Production" by Berkelee College of Music that I’m taking online via Coursera.org

We were tasked to teach any topic from the first week's lessons. I chose to discuss the first characteristic or property of sound called “Propagation”which means sound moving and travelling through a medium.  

Propagation is defined as the act or action  of propagating or to transmission through a medium. Wiki explained that sound is a sequence of waves of pressure that propagates through compressible media such as air or water. http://en.wikipedia.org/wiki/Sound

How sound travels or how it reaches our ears for us to hear the sound?

Sound needs a medium to travel from one place to another or from the source to our ears.  The physical medium can be air, wood, water or metal. Generally, the kind and density of the medium affects the speed of the sound wave.  In other words the arrival time of the sound depends on the medium it goes through in order to reach our ears.

Where does sound travels better?  In air or solid?

I searched the web for fun and interesting experiments to understand where sound travels  better.

Let’s try to quick experiment called “Table Thunder”

 

In this experiment you need a friend, one table and writing materials. Sit opposite your friend. Then knock on the table. Take note how load the sound is. Afterwhich, ask your friend to place his ear against the surface of the table. Knock on the table again. What did you discover?

When you listen to the knocking sound through the table, it is much louder.

What we learned: Sound travels better and louder through a wood, than through air.

For more fun experiments please visit this link.

This lesson that we learned in our experiment leads us to the next  - “Why sound travels better through wood”?

 

 

 

 

 

 

 

 

In How Stuff Works, Jonathan Explained explained that:  “The speed of a sound wave depends upon the medium through which it travels. In general, sound travels faster through solids than through liquids or gases. Also, the denser the medium, the slower sound will travel through it. The same sound will travel at a different speed on a cold day than it would on a warm day.”

The molecules in wood are closer to each or tightly packed other compared to the molecules in water. Instead of jumping from molecules that far aay from each other, the sound easily travels trough the molecules of the wood.

I hope that you learn something. :-)
 

Truly yours,

Cris Garcimo

P.S. For more discussion on Propagation of Sound, you can also visit the following links:

http://www.jhu.edu/virtlab/ray/acoustic.htm

Physics classrom