Question

Topic

Have you ever blown across the top of a bottle and made a sound? If so, did you wonder how that sound was actually created? A bottle can be considered a type of air column. For this discussion, first find two empty bottles of different shapes or sizes. You will use these to try to make your own music.

In your initial discussion post, address the following:

• Of the two bottles, which creates the higher note? Explain why that is the case.
• Add enough water to one of the bottles so that they both will generate the same note. Explain what you did and why it worked. Submit a photo of your setup that shows the bottles and the water levels needed to produce the same note.
• Can you use beats to identify when the bottles are producing the same note? Explain the concept of beats in your own words.

I need typed response only. So don't try to post hand written response. Don't answer if you are not sure about response to this discussion.

Answer 1

When we blow across the top of the bottle we create a pressure wave that propagates through the bottle, and this is what causes the sound.

The frequency of this sound depends on the geometry of the bottle, bottles with a smaller chamber volume and length of the neck, and/or larger cross sectional area of the neck, will produce a higher pitch sound. If we add water to the bottle with larger chamber volume what we do is decrease the effective volume, this way we can even the volume of the two bottles and achieve the same frequency of sound.

When we have two waves that are about the same frequency, a beat is created, this is, the sumperimposition of the waves that results in a higher amplitude pattern. For sound waves this implies higher volume, so using this concept we can identify like notes (this is actually the theory behind tuning musical instruments)