Re: [Phys-l] Cheap Classroom projec to sense water temperature

["CARABAJAL PEREZ, MARCIAL ROBERTO" <mcarabajalp@ypf.com>]

The point of the project is to experience firsthand the copper temperature coefficient value, the difficulties to use it for such purpose, and the suitability of more specific devices such as thermistors. The idea is to use cheap operational amplifiers, or 2-3 transistors, diodes and resistors, and battery. 
The indicator can be any analog or digital tester, or even a few leds.
One team should make this with the original copper coil, another team with carbon resistors, and another team should make similar but with a thermistor. After that, they can develop conclusions.

Thanks very much for all the answers.
Roberto.



-----Mensaje original-----
De: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-bounces@carnot.physics.buffalo.edu] En nombre de John Denker
Enviado el: miércoles, 05 de mayo de 2010 14:47
Para: Forum for Physics Educators
Asunto: Re: [Phys-l] Cheap Classroom projec to sense water temperature

On 05/05/2010 08:06 AM, CARABAJAL PEREZ, MARCIAL ROBERTO wrote:

> We are working in a classroom project to develope a water temperature
> meter. It should be built up with little electronics and using a coil
> of wire copper as temperature sensor device. I would like to know if
> you have seen something like this working and can bring me any
> detail.

I've seen lots of things like that.

Please ask a more specific question.
 -- What is the point of the project?
    If all you wanted was a "water temperature meter", you would
    be better off using a thermistor ... or a liquid-in-glass 
    thermometer.
 -- How much is "little electronics"?  
    Does it allow or disallow a digital voltmeter?
 -- Have you tried it?
    What (if anything) was non-trivial or non-obvious about it?
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