1. Waves Part 2: Sound Objectives:
Describe the relationship between wavelength and frequency.
Explain how a wave’s energy and amplitude are related.
Explain how interference, resonance, refraction and reflection affect sound waves.
Measure and analyze different dimensions of tuning forks and make connections to the frequency of the fork.

2. In your own words: What is the definition of sound?
Warm Up
In your own words: What is the definition of sound?

3. Definition:
What is sound?
Sound is a longitudinal wave which travels through a medium through a series of compressions and rarefactions.
(So… What is compression? What is rarefaction???)

4. Compression and Rarefaction
On a longitudinal wave, the area squeezed together is called the compression.
The areas s p r e a d out are called the rarefaction.

5. Tuning fork lab

6. Tuning fork lab
Get a tuning fork, rubber pad, ruler, and lab sheet, then follow the directions:
How to properly make a sound with the tuning fork (see demo)
How to measure the length, width, and thickness of the tuning fork’s tines (see below)
Width
(both tines)
Depth
(only one tine)
Length
(end to elbow)

7. Tuning fork lab Discussion:
Make a hypothesis for why your tuning fork might sound different than someone else’s, based on the data you collected.
So how does a tuning fork produce sound? (Think about the actions of compression and rarefaction). Diagram if you wish.
 In your own words, explain:
Why do we hear different sounds when comparing different tuning forks? (Review your set of data to help you explain.)

8. GUIDED NOTES, Part two
So, how does sound travel?
A: Longitudinal Waves (also known as Compression Waves)
In a longitudinal wave, the matter in the wave moves back and forth, parallel to the direction of the wave

9. So, how is sound produced?
Sound needs a medium to travel in!
Sound starts as vibrations, moving molecules through the air in the form of a longitudinal (compression) wave. In a tuning fork:
(Remember that light travels as transverse waves (wave motion is perpendicular to direction) and needs no medium to travel in!)

10. Can we only hear sound in the air?
Sound travels as vibrations moving through the air as a compression wave.
Sound travels through air, but travels through other types of medium as well.
Whales communicate through long distances by producing sounds under water.

11. WAKE UP!!!

12. Summary On a scale of 1-5, how well do you understand today’s lesson?
5 meaning you are an expert and can teach this to another student
1 meaning you do not understand
What’s wrong with this video? (HINT: LISTEN and answer in terms of what sound needs in order to travel!)

13. Bonus (If time)
What other ways can you describe the differences in your data with the two other groups? Think about how data can be shown.
Take your tuning fork and find the white key on the electric piano that matches the sound of your fork. Check with Corts to see if you have correctly matched the sound!

14. Sound travels through different media.
We hear sound which usually travels through air. Sound travels through other media as well, such as water and various solids.
Sound travels different speeds in different media. Sound typically travels faster in a solid that a liquid and faster in a liquid than a gas.
The denser the medium, the faster sound will travel.
The higher the temperature, the faster the particles of the medium will move and the faster the particles will carry the sound.