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Using Arduino => General Electronics => Topic started by: omarAlwaadh on Oct 24, 2016, 09:46 am

Title: percentage of water in the human body
Post by: omarAlwaadh on Oct 24, 2016, 09:46 am
Hi every one,

Is there any sensor to Measuring the percentage of water in the human body?
And what is it? what is the name of the sensor?
 
Title: Re: percentage of water in the human body
Post by: raschemmel on Oct 24, 2016, 09:49 am
Is this your homework assignment ? (http://www.projectwet.org/sites/default/files/content/documents/hydration-activities.pdf)

I'm going to take a leap here but isn't the answer to your question a blood test ?

Are there any doctors out there who can answer that question ? (Dr. Arduino ?)

If you just take the time to GOOGLE "BODY WATER" this  (https://en.wikipedia.org/wiki/Body_water)is what you find.

Quote
Total body water can be determined using Flowing afterglow mass spectrometry measurement of deuterium abundance in breath samples from individuals.
So really all you need is a mass spectrometer.
(and breath mints ?)
Check Sparkfun or Adafruit...
Title: Re: percentage of water in the human body
Post by: Grumpy_Mike on Oct 24, 2016, 12:01 pm
Is there any sensor to Measuring the percentage of water in the human body?
No.
Title: Re: percentage of water in the human body
Post by: CrossRoads on Oct 24, 2016, 08:28 pm
Pretty sure I remember 95% from a old Star Trek episode where victims got turned into little blocks.
About $5 worth of chemicals.
Title: Re: percentage of water in the human body
Post by: Jiggy-Ninja on Oct 24, 2016, 09:13 pm
The procedure is as follows:

1) Weigh the thing
2) Dry the thing out in a warm oven
3) Weigh the thing again. The difference is the water weight of the original thing.

Needless to say, this is a very destructive procedure.
Title: Re: percentage of water in the human body
Post by: larryd on Oct 24, 2016, 09:38 pm
Agreed.
Weigh the person.
Put them into a test tube.
Heat contents to remove all the water.
Weight, compare remaining ashes to the original weight value.


.
Title: Re: percentage of water in the human body
Post by: INTP on Oct 24, 2016, 09:49 pm
Hydrostatic testing gives the best estimate of composition, and even then it stands on quite a few guesstimations for the final numbers.
Title: Re: percentage of water in the human body
Post by: raschemmel on Oct 24, 2016, 10:22 pm
You  need a cadaver to weigh before and after

Seriously,  google says gas spectrometry of breath sample. (Google : "body water (https://en.wikipedia.org/wiki/Body_water)")
Title: Re: percentage of water in the human body
Post by: Due_unto on Oct 24, 2016, 10:26 pm
I wonder how those Fitness scales, the ones with the conductive pads you stand on with bare feet, do it.  Whenever I get on it it always tells me my water percentage is somewhere around 50%.  Funny, I don't feel or look like a prune (to most people, anyway!)
Title: Re: percentage of water in the human body
Post by: INTP on Oct 24, 2016, 11:07 pm
Those scales use crude formulas with plugging in galvanic skin response
Title: Re: percentage of water in the human body
Post by: Grumpy_Mike on Oct 25, 2016, 04:35 pm
Quote
I wonder how those Fitness scales, the ones with the conductive pads you stand on with bare feet, do it.
Basically they don't.
Title: Re: percentage of water in the human body
Post by: MarkT on Oct 26, 2016, 03:42 am
Hi every one,

Is there any sensor to Measuring the percentage of water in the human body?
And what is it? what is the name of the sensor?
 
Yes, an MRI scanner can probably answer that, as you can scan for all hydrogen atoms in particular
chemical environments, such as water-water hydrogen bonds.  Of course the definition
of water in a living cell is fraught with issues such as do you count water molecules in
permanent association with protein molecules, etc.

There is no cheap sensor to answer the question.
Title: Re: percentage of water in the human body
Post by: Jiggy-Ninja on Oct 26, 2016, 06:16 am
Basically they don't.
Just like those treadmills that tell you how many calories you burned.
Title: Re: percentage of water in the human body
Post by: ChrisTenone on Oct 26, 2016, 07:37 am
Your liver is gonna be a lot wetter than your hip bone, so when you say % water, are you speaking of the average? How precise do you need to know? It sounds nefarious (unless it is a school assignment, then ok.)

Jiggy-Ninja has the basic procedure, but I would suggest homogenizing the sample first, and taking a smaller aliquot to dehydrate. I would run a complete temp vs weight curve, to account for dissolved gasses, volitile organics, and the like.

Ok, gross, right? How about selecting a part of the body that you normally discard, like your hair after a haircut. An experiment always gives you an answer. Your skill as a scientist will determine the meaning of that answer.

Anybody can just google the answer, but wouldn't you like to present something different?

ps, and since you posted here, you'll need to work an Arduino in somehow.
Title: Re: percentage of water in the human body
Post by: MarkT on Oct 26, 2016, 11:25 am
I like this answer: "if the subject is alive the percentage of water is correct" - so a heart-rate monitor
sensor would do the job!
Title: Re: percentage of water in the human body
Post by: INTP on Oct 26, 2016, 05:25 pm
70%. If someone disagrees with you, then have them prove otherwise. Done.