Something new for spin class

[Carl Sundquist]

Having a sadistic moment, I gave the manager of my local fitness center an
infrared thermometer to use on the flywheels of the spin bikes. My thought
was that the heat generated on the flywheels would give a rough indication
of total watts generated during a spin class. No more faking hard efforts.
We tried it last week and although the flywheel on the bike I rode was hot
enough to jerk your hand away in surprise if you weren't expecting it, the
thermometer only registered 88 degrees F. I aimed it at my bare leg and it
registered 90, so the temperature calibration can't be too far off. But why
wouldn't it read higher on the obviously warmer flywheel? It has a laser
pointer, so you know where the temperature is being measured. I don't know
if the chrome on the flywheel can somehow reflect a bad reading.
Suggestions?

BTW, these little laser guided, non-contact thermometers are a lot of fun.
Use one and you'll be walking all around your house, car, etc measuring the
temperature of everything in sight.

[William Asher]

Carl Sundquist wrote:

> Having a sadistic moment, I gave the manager of my local fitness
> center an infrared thermometer to use on the flywheels of the spin
> bikes. My thought was that the heat generated on the flywheels would
> give a rough indication of total watts generated during a spin class.
> No more faking hard efforts. We tried it last week and although the
> flywheel on the bike I rode was hot enough to jerk your hand away in
> surprise if you weren't expecting it, the thermometer only registered
> 88 degrees F. I aimed it at my bare leg and it registered 90, so the
> temperature calibration can't be too far off. But why wouldn't it read
> higher on the obviously warmer flywheel? It has a laser pointer, so
> you know where the temperature is being measured. I don't know if the
> chrome on the flywheel can somehow reflect a bad reading. Suggestions?
>
> BTW, these little laser guided, non-contact thermometers are a lot of
> fun. Use one and you'll be walking all around your house, car, etc
> measuring the temperature of everything in sight.
>
>
>

The emissivity of the metal in the infrared region is less than one. The
emissivity of your leg is a lot closer to one so the blackbody temperature
in the IR is closer to the physical temperature. The emissivity of water
is an important parameter if you are interested in precisely measuring the
ocean surface temperature from space. Of course, if you want to do that
you probably have no life.

--
Bill Asher

[Phil Holman]

"Carl Sundquist" > wrote in message
...
> Having a sadistic moment, I gave the manager of my local fitness
> center an infrared thermometer to use on the flywheels of the spin
> bikes. My thought was that the heat generated on the flywheels would
> give a rough indication of total watts generated during a spin class.
> No more faking hard efforts. We tried it last week and although the
> flywheel on the bike I rode was hot enough to jerk your hand away in
> surprise if you weren't expecting it, the thermometer only registered
> 88 degrees F. I aimed it at my bare leg and it registered 90, so the
> temperature calibration can't be too far off. But why wouldn't it read
> higher on the obviously warmer flywheel? It has a laser pointer, so
> you know where the temperature is being measured. I don't know if the
> chrome on the flywheel can somehow reflect a bad reading. Suggestions?
>
> BTW, these little laser guided, non-contact thermometers are a lot of
> fun. Use one and you'll be walking all around your house, car, etc
> measuring the temperature of everything in sight.

http://groups.google.com/group/rec.bicycles.tech/browse_thread/thread/9de46fffb043ae2/5aa5968dd917b870?lnk=gst&q=Power+measurement+for+spin+class&rnum=1&hl=en#5aa5968dd917b870

Phil H

[Tom_A]

Carl Sundquist wrote:
> Having a sadistic moment, I gave the manager of my local fitness center an
> infrared thermometer to use on the flywheels of the spin bikes. My thought
> was that the heat generated on the flywheels would give a rough indication
> of total watts generated during a spin class. No more faking hard efforts.
> We tried it last week and although the flywheel on the bike I rode was hot
> enough to jerk your hand away in surprise if you weren't expecting it, the
> thermometer only registered 88 degrees F. I aimed it at my bare leg and it
> registered 90, so the temperature calibration can't be too far off. But why
> wouldn't it read higher on the obviously warmer flywheel? It has a laser
> pointer, so you know where the temperature is being measured. I don't know
> if the chrome on the flywheel can somehow reflect a bad reading.
> Suggestions?
>
> BTW, these little laser guided, non-contact thermometers are a lot of fun.
> Use one and you'll be walking all around your house, car, etc measuring the
> temperature of everything in sight.

Put a piece of tape on that flywheel (or anything else organic like
paint, etc.) and then point the IR thermometer at it. Most likely the
thing is calibrated for an emmissivity (basically how well an object
absorbs or emits IR energy as compared to an "ideal") of ~0.9. Like
another poster said...shiny metal ain't 0.9.

One more thing to remember...the "temp sensors" in your hand don't
really "measure" temperature...they actually measure heat flux, or how
fast the energy is being dumped into your skin. Something with a high
conductivity and high thermal mass will "feel" a lot hotter than
something with the opposite properties at the exact same temperature.

I hate spin bikes....

[Donald Munro]

Carl Sundquist wrote:
> BTW, these little laser guided, non-contact thermometers are a lot of fun.
> Use one and you'll be walking all around your house, car, etc measuring the
> temperature of everything in sight.

Can you use it to measure how hot a chick is (If so perhaps heather will
volunteer for calibration duties).

[Carl Sundquist]

"Donald Munro" > wrote in message
. com...
> Carl Sundquist wrote:
>> BTW, these little laser guided, non-contact thermometers are a lot of
>> fun.
>> Use one and you'll be walking all around your house, car, etc measuring
>> the
>> temperature of everything in sight.
>
> Can you use it to measure how hot a chick is (If so perhaps heather will
> volunteer for calibration duties).
>

Doubtful, since hottitude is a subjective, not absolute value. But that
doesn't mean you can't have fun pointing the laser at her.

[Donald Munro]

Carl Sundquist wrote:
>>> BTW, these little laser guided, non-contact thermometers are a lot of
>>> fun.

Donald Munro wrote:
>> Can you use it to measure how hot a chick is (If so perhaps heather will
>> volunteer for calibration duties).

Carl Sundquist wrote:
> Doubtful, since hottitude is a subjective, not absolute value. But that
> doesn't mean you can't have fun pointing the laser at her.

Confusing a thermometer with a vibrator is a Rumsfeldian attribute.

[RonSonic]

On Fri, 15 Dec 2006 12:01:52 -0600, "Carl Sundquist" > wrote:

>
>"Donald Munro" > wrote in message
. com...
>> Carl Sundquist wrote:
>>> BTW, these little laser guided, non-contact thermometers are a lot of
>>> fun.
>>> Use one and you'll be walking all around your house, car, etc measuring
>>> the
>>> temperature of everything in sight.
>>
>> Can you use it to measure how hot a chick is (If so perhaps heather will
>> volunteer for calibration duties).
>>
>
>Doubtful, since hottitude is a subjective, not absolute value. But that
>doesn't mean you can't have fun pointing the laser at her.

It is an absolute value, measured in milliHelens. The exact measuring process is
slow and requires counting ships at sea.

Ron