Chemistry of common things: Difference between revisions
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You may contain 70% water but basically none of it is in liquid form. | You may contain 70% water but basically none of it is in liquid form. | ||
It's not like there's a pouch. | It's not like there's a pouch. | ||
Your intestine will aborb it into your blood, | Your intestine will aborb it into your blood, | ||
but unless your body needs it and engages the chemistry needed to do so, you will actually pee it out soon after. | but unless your body ''needs'' it and engages the chemistry needed to do so, you will actually pee it out soon after. | ||
If you try to drink a liter of water to fix dehydration, you will probably effectively only get a small portion of that. | |||
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===Mild dehydration=== | |||
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Dehydration is often though of as an immediate thing - e.g. being low enough that specific parts of your body have problems functioning and you are uncomfortable. | |||
Chronic dehydration just means less hydrated on average than you perhaps should be, | |||
enough to start seeing some of these effects but without immediate discomfort. | |||
Depending on your habits, you may do this for years, and it can lead to a collection of slight symptoms | |||
that are mostly not very unhealthy, but can indicate you might feel a little better hydrating a litte more. | |||
This includes: | |||
* more muscle knots | |||
: lower lower blood pressure can mean lower bloodflow, less inter fiber space, which leads to the stickiness we tend to describe as muscle knots. | |||
* loss of concentration | |||
* | |||
Apparently the thirst sensation lessens with age, | |||
"Free water" | |||
[https://en.wikipedia.org/wiki/Free_water_clearance Free water clearance] is about the body's rate of moving out solute and water. | |||
Renal clearance as a whole system is more complex, and you don't need to know most of that. | |||
You also see the concept of "free water ''in something you drink''". | |||
The medical take on that is roughly "when you drink something, how much of that water ''isn't'' required by your kidneys to get rid of the other stuff in there?" | |||
The use by dieticians might be "how much of it is solute" ignores what that solute actually is. | |||
To illustrate why that can be very different[https://www.jandonline.org/article/S0002-8223(96)00608-6/fulltext]: | |||
* saline solution is roughly roughly 0.9% salt. That's basically 0% free water, because that's ''at'' the blood concentration, and ''above'' the body's concentration. | |||
* Sugarwater is ''mostly'' free water, even at the same or higher percentages, because that's taken up into the body (via blood sugar) | |||
:: (...until you drink a lot of it. You're putting things into a system that has a buffer) | |||
Also relevant is [https://en.wikipedia.org/wiki/Intravenous_sugar_solution intravenous sugar solution] - e.g. D5W ("5% dextrose in water)") used in hospitals | |||
to avoid low blood sugar after operations, particularly when it is hard to eat. | |||
: ...which can lead to low blood electrolytes (sodium mostly) unless it's actually mixed with saline solution. | |||
Some sports drink advertising tonicity but actually talking about sugar or a mix is... not very clear. | |||
This still ignores what happens over time. | |||
Say, part of the water in that drink will be peed out within little time just because it's diluting your blood. | |||
You in fact cannot hydrate very quickly. | |||
This is part of why hydration is more about drinking often, than it is about drinking a lot.{{verify}} | |||
https://en.wikipedia.org/wiki/Free_water_clearance | |||
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There is advice that says that sipping water is better, or that guzzling water may dehydrate you. | There is advice that says that sipping water is better, or that guzzling water may dehydrate you. | ||
Depending on how it's said, this is either misleading | |||
Depending on how it's said, this is either misleading (sometimes plain wrong). | |||
...and yet there is a very useful thought and intention behind this. | |||
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: Drinking a large amount of water in a very short time means said absorbing process isn't fast enough, and it starts to diluting your blood enough to feel bloated, and your liver makes you pee to compensate for that. | : Drinking a large amount of water in a very short time means said absorbing process isn't fast enough, and it starts to diluting your blood enough to feel bloated, and your liver makes you pee to compensate for that. | ||
Its not the way you put that into your esophagus. It's the time. And 'sipping' doesn't imply the amount of time spreading you need to get more out of the same wayer. | |||
It does not '''de'''hydrate you, it doesn't actually do much for you either. | |||
Even if the levels are well below [https://en.wikipedia.org/wiki/Hyponatremia hyponatremia]'s effects (bloating, hard to focus) or [[water poisoning]], | |||
it still means it won't hydrate you ''as much'' for the same amount of water, | |||
but it's still a noticeable net-positive effect, so unless drinking water is scarce, it's a non-issue. | |||
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===Erring on the overhydrated or underhydrated side?=== | |||
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That said, you probably don't want to drink so much water anyway. | That said, you probably don't want to drink so much water anyway. | ||
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Your body needs perhaps 3 liters of water per day. | Your body needs perhaps 3 liters of water per day. | ||
Or rather, that's the figure for | |||
: temperate climate | : a temperate climate | ||
: without much activity (so without much sweating) | : without much activity (so without much sweating) | ||
: a middle aged adult | : a middle aged adult | ||
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Most of your food isn't dry, e.g. fruits and veggies are mostly water, so also count. | Most of your food isn't dry, e.g. fruits and veggies are mostly water, so also count. | ||
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===Coffee=== | ===Coffee's effect on hydration=== | ||
{{stub}} | {{stub}} | ||
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===Alcohol=== | ===Alcohol's effect on hydration=== | ||
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Latest revision as of 12:16, 30 August 2023
Cooking
Doughs
See Doughs, batters, leaveners
Greenery
Trees, O2, CO2
Water
On hydration
Mild dehydration
Drinking slowly?
Erring on the overhydrated or underhydrated side?
3 liters a day, or less?
Coffee's effect on hydration
Alcohol's effect on hydration
On water poisoning
Water poisoning happens when drinking a large amount in a short time, because you dilute (primarily) the balance of salt and other electrolytes.
At some point, this starts affecting cellular function in general, which what we mean when we say water poisoning.
Most of your body contains something like 0.15% salt, and you don't want it to be a lot lower or higher
...except in your blood, which is roughly 0.9% salt. It's higher mainly because it's a big part of regulating the salt levels in your body.
So diluting your blood significantly leads to losing that ability to regulate.
You will probably notice being low in salt as headache,
poorer muscle control,
and possibly vomiting and diarrhea (possibly your body trying to correct things?(verify)).
The fact that you will feel bad, and have probably associated "I feel bloated, I probably need to stop drinking water" is why most people are at negligible risk. (though if you instead confuse it with "I'm dehydrated, I need to drink water", that's not great)
Time is a significant factor, in part in part because your kidneys are happy to make you pee a lot more
- so drinking liters more than you need over a day is much less of an issue than drinking the same amount within an hour
- peeing that much wastes some salt in the process, but not very much(verify)
Another part of it is that it takes a while for you to absorb water you drink (basically while it's in your gut) - if there's a lot, there isn't enough time to absorb it.
The time factor is why you see statements like "stay under 3-4 liters of water within in a few hours".
Doesn't distilled water do this a lot quicker?
No.
Sure, tap water and bottled water has things beyond H2O, including sodium.
When your blood carries something like 0.9% salt (because it's the means of interchange; the rest of your body contains something like 0.15% salt), the difference between 0.003% in tap water and and 0.000% (in theory) in distilled water is two orders of magnitude lower, so the difference is between "almost entirely no salt" and "entirely no salt".
In fancier talk, the osmolality of both is so low that they are almost equally hypotonic, so have roughly the same osmotic effect on your body.
Which is why quickly drinking liters of almost any water based drink will do this, basically because most water based drinks are almost entirely water.
On bottled water
On filtering water
Activated carbon
Demineralized and distilled water
Distilled water is (nearly-)pure H2O, because distillation means you move the water and leave behind most other things.
Demineralized water means few to no minerals
- ...(unlike fresh natural water, which tends to have minerals in it e.g. due to limestone. Tapwater has more controlled bunch of these things; see also hard water)
- ...but says little about what else may still be in there
- it's useful to keep minerals out of clothes irons (which you want largely to avoid limescale), car batteries (which you want to avoid self-discharge and corrosion), and such.
On contents of demineralized water
Demineralized water often mentions it is not fit for consumption
- in practice it's usually pretty clean water, but it's not guaranteed to be pure
- largely because depending on the process of demineralization, there may be other things still left in there, say, a few bacteria. Your iron or car battery won't care, but you might
- and because it doesn't matter for the intended uses
- (also in part because it's also sold in supermarkets, so it's useful, possibly required, to point this out explicitly)
Does distilled or demineralized water lead to nutritional deficiency?
Water hardness
Hard water refers to water having relatively high mineral content.
Since we're usually talking about fresh water we want to use as drinking water, this focuses mainly on calcium (also magnesium) as this is a common component that comes naturally from the water passing through limestone, chalk, gypsum, or such.
Which gives you things like calcium and magnesium carbonates, bicarbonates, and sulfates.
High is relative - for calcium we're talking talking parts per million, where
- soft water is on the order of 30ppm,
- hard water on the order of 150ppm.
- you get something like 700ppm in a few places
Many other things can qualify for 'mineral content', but typically the amounts are very small,
and/or their appearance is local. (e.g. iron, aluminium, manganese)
Salt is one, in that seawater is technically very hard (6000+ ppm) due to its salt, but since it doesn't evaporate, this doesn't apply to fresh water.
Would you prefer soft or hard water?
It's a few different practical considerations, and none of them are hugely important - and the mentioned effects are frequently overstated.
Arguments for softer:
- aesthetic:
- softer water deposits less scale in showers, drinking glasses, and such
- cost
- softer water deposits less limescale in washing machines, kettles, which can make them last longer (thick scale makes heating less efficient and in extreme cases causes overheating)
- soaps lather more, and you need less detergent (or separate water softener) - can be overstated since many contain softeners anyway
- harder water is less ideal for some industrial processes (and needs fewer additives)
- with soft water, washing clothes wears the fibers a little less
Arguments for harder:
- softer water will pull out metal out of pipes over time, corroding unlined metal pipes more quickly
- (more of a net end effect - there are a handful of other factors on corrosion speed)
- which means water infrastructure can be cheaper to run, particularly that infrastructure is currently older, cheaper pipes.
- Harder water could be considered a dietary supplement
- though this is frequently overstated. The difference from this switch stays is from 'tiny' to 'small' on your calcium needs, and you need to get your minerals elsewhere anyway.
Arguments for either
- "this water tastes nicer" - you probably prefer what you're used to
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See also:
Water containers getting slippery after a while
Fluoride in drinking water
Salty water
Greywater
Electrical resistance of water
See Electronics_notes/Resistors#Resistance_of_fluids