1. The Pitch of Sound
By collaborating in experiments on different ways of producing sound from vibrations, I can demonstrate how to change the pitch of sound. SCN 1-11a.

2. Today we are going to … Review what sound is, and how it travels
Learn how to adjust the pitch of sound.
And we will…
Be able to demonstrate how to change the pitch of sound.

3. We know that sound is a form of energy and a vibration that can travel through solids, liquids and gasses.
The vibrations enter your ear, and you hear this as sound.
The air particles around the object vibrate…
When objects vibrate…

4. The pitch of the sound is a measure of how…
HIGH or
LOW
…The sound is

5. We can experiment with the pitch of sound using some very sophisticated scientific technology…
A ruler!

6. Try this now!
Ping the ruler off the edge of your desk, watch the vibrations and listen to the sound it makes! (be careful not to snap it!)
How do the vibrations and sounds change when you alter the length of the ruler?

7. What’s going on? When you rerelease the ruler?
It vibrates (moves back and forward rapidly), causing the air around it to vibrate as well.  When these vibrations reach your ear, they are interpreted by your brain as sound. These vibrations are called sound waves.
When you alter the length of the ruler?
The pitch of the ruler was higher as the length of the vibrating part of the ruler was made shorter.  
The pitch of a sound is controlled by the speed of the vibrations.  The faster the vibrations, the higher the pitch of the sound.  The slower the vibrations, the lower the pitch of the sound. 

8. Which part of the guitar causes the vibration?
We can change the pitch of musical instruments, like guitars!
Which part of the guitar causes the vibration?
The strings!

9. We can experiment with the pitch of sound using some string…
Your teacher will give you 3 pieces of string of different sizes. Work with a partner to complete this experiment…
One person should hold each end of the string in their hands and pull it tight, your partner should pluck the string and listen to the sound made

10. What did you notice?
The longer the piece of string the lower the lower the pitch of sound produced.
The shorter the piece of string, the higher the pitch of sound produced.

11. Today we have… Learnt what the ‘pitch’ of sound is
Investigated how to change the pitch of sound.