Date: Wed Oct 28 09:08:50 2009 ** **Back to Contents ** ------------------------------------------------------------------------ **

Author: Sam Sampere

Subject: Re: c

Post:

I never did like that experiment. First, who says there are standing wave in a microwave? That could be true, but I've never seen proof. And wouldn't the hot spots be at lambda/2?

I'd like her better if dad didn't screw up the physics ;)

Later,

Sam

-----Original Message-----
From: tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On Behalf Of fletcher@physics.usyd.edu.au
Sent: Wednesday, October 28, 2009 7:14 AM
To: tap-l@lists.ncsu.edu; Kenn Lonnquist
Subject: Re: [tap-l] c


I want to enroll this future student

http://www.youtube.com/watch?v=9O2Keu6o3i0




Quoting Kenn Lonnquist :

> Brian-
>
> I have done this using fairly fresh "mini" marshmallows, and I will
> generally cover a whole plate with them. That way, when they do expand,
> there is not much side-to-side motion. After melting a bit (i have not
> waited for them to burn, but perhaps the marking is clearer then) I stop the
> microwave and let them cool. As they cool, they settle back down, without
> much horizontal shrinkage. Often, I can get within several percent from
> these measurements.
>
> Kenn
>
> On Tue, Oct 27, 2009 at 5:20 PM, Brian Huang wrote:
>
>> Matt, or anyone else out there -
>>
>> I tried this the other day, but the marshmallows just blew up (inflated).
>> I started to get some brown spots to measure, but since the marshmallow
>> moved too, I was unable to get an accurate reading. I'd love to see your
>> write-up. And, is there a specific type of marshmallow that works best?
>>
>> Thanks!
>>
>> Brian Huang
>> Lafayette, CO
>>
>>
>>
>>
>> On Fri, Sep 11, 2009 at 8:27 AM, Matt Lowry wrote:
>>
>>> Hi Sean,
>>>
>>>
>>>
>>> You can do it with a microwave oven rather simply by measuring the
>>> distance between â??hot spotsâ?? on, say, a bed of marshmallows. That distance
>>> is half of a wavelength, and the standard microwave oven operates at a
>>> frequency of about 2.45 GHz. Multiply the wavelength by the frequency and
>>> youâ??ve got the speed of light. I have my students do this every year, many
>>> to within 5% of the actual value.
>>>
>>>
>>>
>>> If youâ??re interested, let me know and I can send you the writeup I give to
>>> my students on how to make all the measurements.
>>>
>>>
>>>
>>> Cheers,
>>>
>>>
>>>
>>> Matt Lowry
>>>
>>> Lake Forest High School
>>>
>>> College of Lake County
>>>
>>> Illinois
>>>
>>>
>>>
>>>
>>>
>>> *From:* tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] *On
>>> Behalf Of *Lally, Sean
>>> *Sent:* Friday, September 11, 2009 8:17 AM
>>> *To:* 'tap-l@lists.ncsu.edu'
>>> *Subject:* [tap-l] c
>>>
>>>
>>>
>>> Folks,
>>>
>>>
>>>
>>> Any good suggestions for measuring â??câ?? on the cheap?
>>>
>>>
>>>
>>> Sean
>>>
>>>
>>>
>>
>>
>
>
> --
> Kenneth Lonnquist
> Assistant Coordinator, Introductory Physics Labs
> KennLonnquist@gmail.com
> 970.491.2540
> Physics Department
> Colorado State University
>



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From tap-l-owner@lists.ncsu.edu Wed Oct 28 09:08:50 2009
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