Why does water taste different?

Question

after you leave it in a glass for a few hours.

E.g You get a glass and you fill it with tap water and you drink it immediately (and why wouldn't you, its common sense) but when you leave it for a few hours and then you drink it, it tastes different.

Answer 1

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for one thing, the temperature makes a difference.
try something.
get a couple glasses of water, put on in the frig and leave the other out.
after a few hours, get another and put it in the frig for 15-20 minutes.
then taste all 3.
along with one directly out of the tap.
i'm betting that the one you leave out will be the most different.
just the temperature makes the difference.

however, depending on the chlorine in your water, sometimes it evaporates out.
that would happen far more to the glass that's left out because as water warms, it holds less gas.

Answer 2

I would imagine this: There are gases (like carbon dioxide, oxygen, etc)
dissolved in water. When water is heated, these gases are less soluble
in the water. When you boil water, the bubbling is dissolved gases being
released. So I would say that leaving a glass of water siting out
lets the water "warm" up and those bubbles are bubbles of oxygen, carbon
dioxide, etc being released

THESE GASES CHANGE THE TASTE OF THE WATER!!!!!

Answer 3

water is a universal solvent... among other things, it holds a certain amount of air... as water tumbles from the faucet into the glass, a certain amount of air gets dissolved and suspended in the water... that's why fish can "breathe" in a fishbowl as long as you keep a bubbler going.... after a few hours sitting on the counter... this air escapes from the water or, put another way, the water becomes "stale"

Answer 4

The chlorine in the water evaporates out when tap water is left standing for a long time.