where does water go when you drink it?
 

Once, I decided to conduct a little experiment. I weighed myself. I drank a tall glass of water. I weighed myself again. I drank the same amount of water again. I weighed myself a final time.

The first glass of water caused my weight to increase by 4 lbs and the second glass only by 1 lb.

Obviously, I use the term "experiment" loosely here. I didn't really know what I expected to happen, but that certainly wasn't it. Furthermore, I don't understand why this happened. Can somebody please explain this to me?

were you using a bathroom scale? i doubt you drank 5 pounds of water

yeah, it was a digital bathroom scale - but I weighed myself a few times before I started to make sure it was precise!

That's an odd one dude. Not sure how one of them made it 4 pounds, the next was only 1 pound. If you do this again, measure the water's weight before you drink. I'd like to see what 4 pound glass of water looks like.

:lol:

4 pounds of water would probably make you feel sick

Standing differently on the scale probably caused your disparity. I can make mine go up or down 3-4 pounds by leaning to one side.
Try to stand directly in the middle with feet touching.

Yeah, repeat you experiment without ever leaving the scale. Weigh yourself, have someone hand you the water, drink it, then hand it back, weigh yourself again, repeat as desired.

Aside: At room temperature, the density of water is essentially one g/ml or one kg/l. Now, I doubt that you drank a whole litre of water, but it is quite conceivable that a large glass would hold half a litre. So you probably drank half a kilo of water, just over 1 pound.

"a pints a pound a world around" thats how i remember the weight....

so 1 cup should be about half a pound and 1 quart would be about 2 pounds

I doubt you drank 2.5 quarts

as for the weight discrepency... i had a scale that depending on how far forward or back you stood on it it would vary in a range of 5 lbs...

1 gallon of water = 8.34 pounds.

I have to add here, scientifically speaking, a single sample doesn't make an average. If your interensted in the weight of a glass of water, weigh yourself with the empty glass, then, while still on the scale, fill the water. The weight should change only based on the weight of the water.


i understand where your going, which is "if I eat one pound of donuts, why do I gain 5 pounds?" kind of thing, but remember, calories are a reference to the available energy of a given food stuff, not necessarily the pound weight. ;)

but not in terms of food lbs, in terms of real weight, if u weigh one pound of donuts would u really gain 5 pounds?

Eventually. But 1) I'm asking about a glass of water, and 2) I weighed myself minutes after a drank it. What I'm curious about is what body processes occur in the moments after you drink water. (And if those processes sufficiently explain my pseudo-experiment.) I realize that there could be flaws with the scale, and that MAYBE I was standing on a slightly different part of it or leaning or something, but I don't think I did it enough to make a 3-lb difference. I was playing with the scale all weekend and I was standing on it pretty consistently by the time I did the water thing.

The same bodily processes that are taking place so long as you continue to be alive, e.g. circulation, respiration, digestion, waste elimination from the bloodstream via the kidneys, replacement of skin, hair, and nails, and of course the hamsters running in the wheels upstairs thinking about the next post on TFP. :crazy:

no. at least, i don't think so. lets say you eat donuts adding up to 1 kg of mass (it's weight would be 2.2 lbs, but kgs work easier for this example, i think). 9 fat calories weigh 1 gram. 1 pound of fat would be 3500 caloreies, so 1 kg would be about 1600 calories. basically, if you ate a donut made of 100% fat, you would gain whatever amount of that fat that wasn't burned.

therefore, if you ate a 1kg donut, you would be eating 9000 calories. which would translate into about 6 kg's worth of fat in the human body, so... i guess i'm wrong. you would gain more...

i guess you could gain more based on how the energy is stored in food vs. how it is stored as human fat.

anyone else got any ideas on this?

Try it the other way, Weight yourself before & after you piss it out & see if you lose 5 pounds!!

This isn't magic, no smoke, no mirrors. If you ingest 5 pounds of water you are 5 pounds heavier.

End of story..

-SF

Whoa, but that glass definitely did NOT hold 5 lbs of water.

I mean, I felt a little dehydrated before I had that first glass and I was extremely relieved after I drank it. I know that that means some kind of necessary body processes were taking place (like my tissues were being supplied with oxygen or some such biological goodness) but I'm not sure exactly what those processes are. I was hoping that somebody on TFP (a doctor or biologist or something) would know and be able to tell me.

It's still the same, if you drink 16oz of water, you will be 1 pound heavier.

Ever heard of the "matter cannot be created or destroyed?"

-SF

it can happen coz the fats/carbohydrates can react with material that would otherwise leave your body.....like oxygen/minerals making them stay in the body

btw, it's energy not matter that can't be destroyed.

Mass is conserved (with the exception of nuclear reactions). Momentum and energy are also conserved.

http://www.mathpages.com/home/kmath407/kmath407.htm

When you start talking about how much you gain from eating something, you have to account for the time it takes you to digest the food, the energy supplied to the body from the air you breath during that time period, anything else you ingest during that time period, the urine and feces that you expel during that time period, and the energy your body consumes during that time period. You're adding in a lot of factors, many of which are difficult to quantify.

The "experiment" that is being referred to is simple. He drinks the water and weighs himself immediately afterwards. From the time he drinks the water to the time that he weighs himself, all he has done is take a few breaths. The mass of the air taken in is negligible since air weighs about 1.2 g/L at standard temperature and pressure and your lungs can only take in a couple liters of air.

To make a long story short, your mass should change by exactly the mass of the water you drank if you wieghed yourself right after you drank the water. The difference in weights is an error.

like the food we eat, water is also exhaled when we breath. molecules are broken down in food and CO2 escapes, thats why you dont deficate the same amount you take in

Yes, but there is a margin. ...and this margin is insufficient to explaining the instintanious, disproportionate gain of mass from 1 glass of water.

-SF

Explain to me how matter is created and destroyed.

-SF

By burning it, for one.

that's not destroying it... just transforming its physical state.

Okay, okay. But that's what I'm asking! Can somebody describe the transformation of water when we drink it (if one occurs at all)? What does the stuff we don't urinate turn into? (I'm looking for a really specific answer here.)

When you drink water, it enters your body, as it touches epithelial tissues, some of it is absorbed into the tissue osmoticially. The same goes for your stomach and small instestines, but only in small amounts. Water is mainly extracted in the large intestine. The large intestine is reponsible for water extraction, this makes your feces more solid.

Water doesen't break down into anything in your body. Water is water. Two Hydrogens and an Oxygen, water is a solvent in a way, a polar solvent, which minerals and other water soluble nutrients are dissolved into. Water makes up about 70% of the human body, and water is the main component in most every fluid in your body.

When your body receives a quantity of water, it is treated as any other 'ingested' substance, water is absorbed through the epitheial tissues, smooth muscle tissues and intestinal villi. Think of villi like alveoli in your lungs. Alveoli are bound capiliaries that exchange gasses in your lungs. Villi promote the exchange of water/fluids/nutrients/salts,etc.

Yeah, in the end, the water that you ingest is absorbed into your body, but it stays water, it just gets dispersed throughout your body, a small part leaves through your feces, and the majority gets excreted by the kidneys.

-SF

I can't help but think that Supple Cow still entertains the idea that he did not gain the water's mass despite having drank it. It is far more reasonable to assume that you made a mistake in conducting your experiment, Supple Cow, than it is to assume that the mass (and thus, weight) of the water was somehow removed by some chemical process occuring in your body because no chemical process can change that water's mass!

That's not quite true. There are many acid/base reactions going on in the body, expecially in the stomach. Water is used in lots of organic chemistry reactions.

Mass and enery are not conserved during nuclear reactions.

True, in a way, water in the presene of an acid/base does freely exchange a hydrogen, but in the end.. ..it is a such a small gain/loss in the quantity of water. I think that it was someone's assumption that water was broken down at its smallest elements for the body to utilitze. It would be great if we could ingest water and strip the oxygen from the molecule and be able to use that oxygen for metabolism. Wishful thinking..

Quote:

Mass and enery are not conserved during nuclear reactions.

Assuming there is not an abundance of nuclear reactions inside the body, we do not have to consider this... Nonetheless, you are correct.
-SF

No, he is not! Where do you guys get these ideas from?

During a nuclear reaction, mass gets turned into energy and it always does so at the same ratio, E=mc^2. This is conservation! If you took that energy and put it back into mass, you will get that mass back...

Sometimes its better to just keep it simple and not introduce a whole other set of ideas that will come under critisicm.

But I guess I got caught.

-SF

Sadly, I understand what you mean, Saltfish. Sometimes it is better not to argue, as can be demonstrated in Tilted Politics, but in this case it helps steer the thread back on topic rather than off it. Someone else tried to complicate the issue by introducing magical nuclear reactions and I was just trying to quell that...

Thanks for deciding that you are the judge of what questions posed by posters other than yourself may be answered, I didn't see the moderator tag under your name. I was merely replying to sf's question of when mass can be created or destroyed.

Conservation of mass and conservation of energy are not meant to apply to nuclear reactions nor are they meant to apply to collisions between matter and anti-matter. At least for nuclear reactions, the mass-energy is conserved but it is not to be thought of separately as conservation of mass and conservation of energy. It's the whole fucking reason why we need E=mc^2!

http://www.chem.umn.edu/class/1022/h...2Ch21Notes.doc

You're welcome.

Actually, I'm having a very hard time understanding what you're trying to say here. In what manner did I decide what questions may be answered?

I was just trying to steer the conversation back to ingesting water and how that affects your mass...

I can't believe this thread has gotten so much play.

16 oz. of water wieghs 1 lb. (roughly). You drink 1 lb. worth of water. You will now weigh 1 lb heavier. The only difference from holding it in your hand and having it in your body is that your stomach is now the container, instead of the glass.

Some mass you may lose due to water vapor in your breath, and sweat. This would be AT MOST 1 oz in extreme conditions over a few minutes.

You have to be making errors in your calculations.

Saltfish, thank you for answering THIS question (3 of your posts ago), which coincidentally had become the only question I had by this point (I had forgotten about the difference in my first and second glasses of water by that point).

[sarcastic femaleness] No, actually - I was no longer entertaining that notion, thank you. Perhaps I should have asked "what processes occur when you drink water" a few more times so as to emphasize that I was no longer asking for people to tell me I had measured incorrectly. I mean, I only got around to asking it twice. [/sarcastic femaleness]

--INSERT CLEAR SEPARATION OF ISSUES HERE--

Excuse my sarcasm. Had I known this thread would degenerate into this, I would have just asked my friend, the biology major. However, I thought that TFP might be able to provide something more insightful than she could.

Please, for the sake of decency, re-read your posts as if you are someone else. Pretend that you have no idea what you are thinking and must, therefore, infer your intent from the words that you have written.

It seems clear to me that your first post mentioned nothing about wanting to know the chemical/biological reactions in your body. You simply wanted to understand how the results of your experiment came about.

Yes, you did introduce a new question in your third post, but...
Okay, so it seems pretty clear that you're still holding on to the idea that your experiment was not flawed and that there must be some scientific explanation to your missing mass.

The next post you made was in response to saltfish:
Whoa, but why do you still care about the volume of the glass of water? Maybe because you still maintain that your experiment was not in error?

After all this, there was only one other post where you mention your chemical/biological question and it was off handed, like:
You'll note that this is the only post where you asked this question without mentioning your experiment and that, from this, you expected us to assume that you had given up the assertion that your experiemnt was accurate. However, you didn't say anything about it, specifically, like "Okay, so I screwed up my experiment," or anything of the sort. You could easily have still been asking these questions to support an experiment that everyone else on this board agrees was most likely erroneous!

Only then did I step in and conjecture that you still entertained this notion and waited for a definite comfirmation or denial.

Of course, that's when the shit hit the fan, for no reason...
If you wanted to "emphasize that [you were] no longer asking for people to tell [you you] had measured incorrectly," why didn't you simply say so, instead of surreptitiously pretending that you had never told us why you were asking all of this in the first place in the desperate hopes that we'd all somehow forget...

Believe me, I didn't enjoy reenacting this whole thread for you all. I'm starting to see some angry faces around here but I honestly see no reason for it...




edit - for some reason, angle brackets didn't show up so I replaced them with square brackets...