Difference between revisions of "Chemistry of common things"

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m (On bottled water)
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There is no true tl;dr on this, because standards on water vary per country.
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There is no true tl;dr on this, because standards on both tap water and bottled water vary per country.
  
And if you consider all the theories people have on it, tis is a many-parter.
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And if you consider all the theories people have on it, this is a many-parter.
  
  
 
But tl;dr
 
But tl;dr
* health-wise, the standards are more or less the same as tap water
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* health-wise, the standards for bottled water are usually more or less the same as tap water
:: sometimes because it mostly just is tap water, sometimes because of actual processes and checking
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: sometimes because it mostly ''is'' tap water, sometimes because of actual processes and checking
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: tap water regulations are usually public knowledge, that for bottled water is often not
 
: tap water regulations are usually public knowledge, that for bottled water is often not
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: it seems tap water is often checked a little more regularly
 
: it seems tap water is often checked a little more regularly
 
: and in some cases it just directly is tap water
 
: and in some cases it just directly is tap water
  
* the base water for tap water is
 
  
* taste-wise, it may taste better than you than the tap water simply because it comes from another area
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* the base water for tap water is usually tap water.
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: sometimes bottled as-is, sometimes processed further
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* taste-wise, it may taste better than your tap water, or just different from it, simply because it comes from another area
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: ...mostly because it has different hardness
  
  
  
 
* claim: "bottled water is healthier for you"
 
* claim: "bottled water is healthier for you"
: ...in what way?  If you believe this without argument, the ads certainly are working
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: If you believe this without ''any'' stated reason, then the ads are certainly working
  
 
* claim: "purified better is better than tap water"
 
* claim: "purified better is better than tap water"
: can be true, depending on the purification method.
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: depends on what you're taking out is bad. Mainly leads to...
: yet bottled does not often mean higher purification standards.
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* claim: "bottled has fewer toxins left by the processing than tap water"
 
* claim: "bottled has fewer toxins left by the processing than tap water"
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: 'toxins' are unspecified [[fud]]. If more specific, it often just means 'leftover chlorine'
 
: background:
 
: background:
:: bottled water is also processed, mostly to filter out some organics and metals that would affect taste. (What that does or doesn't leave in varies, as it depends on the actual process)
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:: when it's not literally just bottled public water, then bottled water is typically processed in similar ways public water is (varies with their water source), mostly to filter out some organics and metals that would affect taste.  
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::: ...what that does or doesn't leave in varies, largely with the actual process used
 
:: tap water is held to stricter standards, and mandates more and more frequent quality tests
 
:: tap water is held to stricter standards, and mandates more and more frequent quality tests
 
:: bottlers are not required to monitor for parasites, or to disinfect when the source is unlikely to have them (which is usually fine)
 
:: bottlers are not required to monitor for parasites, or to disinfect when the source is unlikely to have them (which is usually fine)
 
:: Some bottling companies are good about checks, some not. It's hard to know.
 
:: Some bottling companies are good about checks, some not. It's hard to know.
:: tap water processing kills microrganisms, often with chlorine. Some chlorine is okay, continuous less so, so it's better to remove it. It usually is, but not always.
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:: tap water processing kills microorganisms, often with chlorine. Some chlorine is okay, continuous less so, so it's better to remove it. It usually is, but not always.
 
:: there are alternatives to chlorine, which are somewhat more expensive. (bottling companies don't often use them, though)
 
:: there are alternatives to chlorine, which are somewhat more expensive. (bottling companies don't often use them, though)
: a short conclusion would be that
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: so it depends entirely on the standards, purification, testing method and frequency, and more.
:: in both cases, it depends on the source of water.
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:: and e.g. the testing frequency may be lower for bottled
:: bottled water typically also sees treatment, though it varies
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:: the toxins thing seems to refer mainly to leftover chlorine
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::: chlorine is used to kill microorganisms, which is good
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* chlorine
::: ...but should be removed. If your water clearly tastes chlorinated, ask questions. In this specific case, bottled is probably better.
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: is one way to kill microorganisms (something you want)
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: and has to be removed, but may only be removed to the point they ''have'' to.
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: Yes, if your water clearly tastes chlorinated, ask questions.
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: if bottled water plant takes more effort, then bottled is nicer
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* It also depends on the source of the water, and the cost of the (amount of) processing required
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: which probably varies ''more'' for companies than for public utilities
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==On filtering water==
 
==On filtering water==

Revision as of 17:47, 19 June 2022


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

Oxyhydrogen