Difference between revisions of "Chemistry of common things"
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| − | There is | + | There is advice that says that sipping water is better, and guzzling water may dehydrate you. |
| − | sipping is better, and guzzling water may dehydrate you. | + | |
| + | Depending on how it's said, it's misleading or wrong, but there's a good thought at the core. | ||
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| + | The idea is that | ||
| − | + | Sipping means taking more time to drink the same amount of water, giving your body time to spread the water around. | |
| − | + | Drinking a lot of water in a very short time starts diluting your blood, meaning your liver makes you pee to compensate, so it won't hydrate you ''as much'' for the same amount of water. | |
| − | + | ||
| − | + | But it's still a net-positive effect, so unless drinking water is scarce, it's a non-issue. | |
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| − | |||
| + | That said, you probably don't want to drink so much water anyway. | ||
| − | + | Sure, it's probably good idea to err on the side of a ''little'' too much, than to always be a little dehydrated - but needing a little more water is actually quite common and not really an issue. | |
| − | + | But drinking a ''lot'' too much is something your liver only reacts to slowly, and in the meantime your electrolytes are diluted, meaning | |
| − | But | + | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
: you won't even feel as hydrated. | : you won't even feel as hydrated. | ||
| + | |||
: the low sodium may lead you to bloat a little (meaning water moves into cells, see hyponatremia) | : the low sodium may lead you to bloat a little (meaning water moves into cells, see hyponatremia) | ||
| − | + | ||
| − | + | ||
| − | + | Also, in ''extreme'' cases it's dangerous (see [[water poisoning]]) yet that's hard to do. | |
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| + | You would have to drink multiple liters per hour, quickly and/or consistently. | ||
| + | |||
| + | And most people will stop doing so because it feels bad far before it's dangerous. | ||
| + | Athletes sometimes overdo it, | ||
Revision as of 16:53, 19 June 2022
Contents
Cooking
Doughs
See Doughs, batters, leaveners
Greenery
Trees, O2, CO2
Water
On hydration
Drinking slowly?
3 liters a day, or less?
Coffee
Alcohol
On bottled water
On filtering water
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 (fresh natural water has some, tapwater has a more-controlled bunch; see also hard water) by some method
- ...but says little about what else may still be in there
- it's useful to keep minerals out of chothes irons, car batteries, and such (largely to avoid limescale)
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?
On water poisoning
| This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, or tell me) |
Most of your body contains something like 0.15% salt, and blood 0.9%.
Water poisoning happens when drinking a large amount in a short time,
because of what it does to certain balances in your body, primarily salt and other electrolytes.
If you manage to dilute your body significantly, it starts affecting cellular function in general.
If you manage to dilute your blood significantly, it's part of that mechanism that dilutes your body.
You will probably notice this poor function because it leads to headache, poorer muscle control, possibly vomiting and diarrhea.
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 confuse it with "I'm dehydrated, I need to drink water", that's not great)
Time is a significant factor,
- in part because drinking only moderately more than you need, your kidneys are perfectly happy just making you pee a lot more
- Which wastes some salt in the process, but not very much(verify)
- in part because because it takes a while for you to absorb water you drink, basically while it's in your gut
- (related to why moderately fast rehydration in hospitals is done via saline IVs - it's in multiple ways more practical than something the relies on timing and attention(verify)).
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.
Quickly drinking liters of almost any water based drink will do this, basically because most water based drinks are almost entirely water.
Sure, tap water has things beyond H2O, including sodium. As does bottled water.
The concentrations of these are very low (order of roughly 0.003%(verify).
...and in practice those are more related to tasting like the water you're used to, because these amounts are very low relative to the amounts we need.
- e.g. for salt, it is primarily the salt we add to our food that helps us keep our salt balance, and your cravings will typically guide you to a decent amount of salt (actually, many of us get a little too much salt).
It's also not really how much other-things there is in it, it's how much of that changes the osmotic pressures between it and your body (called its osmolality).
But even if all of the additives in tap water were relevant, the difference between that 0.003% in tap water and 0.000% in distilled water is basically negligible to you drinking it.
...because both are significantly lower than your body's 0.15%. It's one or two orders of magnitude lower. In a practical sense, both are basically zero.
There's a difference you probably measure in lab conditions, but that's about it.
If you're stranded in a desert for weeks, and have the choice of what water to take, maybe, but still not really, in that it'd be a lot more important to catch the salt you sweat out.
And it might actually make a real difference what the non-distilled water is. If it's not regulated tap water, the possibility of pathogens may be a lot more important)
Water hardness
| This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, or tell me) |
Fluoride in drinking water
Salty water
Electrical resistance of water
See Electronics_notes/Resistors#Resistance_of_fluids
