Date: Fri, 28 Oct 2005 16:15:42 -0700

Author: Doug Johnson

Subject: Re: Beaker Breaking Demo Question


The 15cm high plexiglass safety tube that the beaker sets in is
approximately twice the diameter of the beaker. The beaker is ~8.5cm and
the tube is ~17cm. So maybe it is standing waves between the tube wall and
the side of the beaker?

I'll work on this more... Have a great weekend! ...Doug J.

> Hmm... I was thinking the sound cancellation at the mic might be due
>to the distance from the glass, but the numbers don't work out. Is the
>distance from the mic to the glass equal to the diameter of the glass?
> Jerry
>At 08:05 AM 10/28/2005, you wrote:
>>It is about 4 cm. ...Doug J.
>> > What is (was) the distance between the mic and the glass?
>> >
>> >
>> Jerry
>> >
>> >At 03:19 PM 10/26/2005, you wrote:
>> >>The other day, I was setting up our Beaker Breaking Demo and ran across
>> >>something I never noticed before. Using a microphone, when I looked for
>> >>peak resonance(or volume) on the oscilloscope, I got one frequency like
>> >>1263.4 Hertz and when I tweaked it up bit, I got almost total sound
>> >>cancellation on the microphone (outside the sound chamber it was still
>> >>loud) at 1264.2 Hertz...
>> ...Doug J.
> Jerry DiMarco
> Manager of Lecture Demonstrations and Instructional Labs
> Montana State Univ., Physics Dept.
> Bozeman, MT
>Our Motto: "There's a demo in there somewhere."

From Sat Oct 29 00:26:24 2005