Recent comments in /f/askscience

amitym t1_ja5g0lg wrote

Reply to comment by Brilliant_Passage678 in Water on Earth is not Constant. Why ? by ItsDivyamGupta

Well like when it becomes tree-stuff it is often split up, the tree will retain some water as part of its inventory of healthy-tree biomass but also some of the H and some of the O in the H₂O gets turned into sugar and starch and structural carbohydrates and proteins and stuff.

You can regard those other substances as a reservoir for water, in a sense, because over time as they are metabolized or whatever happens to them they may break back down into water again. As part of the tree's life cycle.

But in terms of where it ultimately goes? Sure absolutely, someday the tree will die, and when it dies the tree will decompose, and some part of the tree's biomass will be eaten by bacteria, fungi, and the other usual suspects. During that process much of the tree will be turned back into water again. And then go be part of the soil, from which new sprouts will sprout again, and so on and so forth.

Some statistically minded biologist might be able to give an estimate of how long your average water molecule remains water continuously over a timeframe like that (let's say several hundred years). It might be that a lot of the water a tree consumes just always remains water. Or it might be that most of it changes form! That is an interesting question.

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NotTooDeep t1_ja57gpp wrote

Reply to comment by 4x49ers in Is there any possible relation between the recent earthquakes in Turkey/Syria, Japan and Papua New Guinea? by Corvid-21

Yes. I found that Wikipedia page as well. This also makes me think about situational awareness. That scene in the diner in the original Bourne Identity movie, where he can't recall who he is, but tells the young woman who is helping him about the people and objects in the environment around him and what their meaning is.

I imagine a professional boxer sees arm and foot movements in a different way than someone who has never seen a boxing match.

Your example of the flight over Stonehenge is funny! Thanks for that.

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RCrl t1_ja56lgb wrote

Reply to If the fuel that goes in car engines is extracted from hydrocarbons, which consist of only Hydrogen and Carbon, and those hydrocarbons react with Oxygen in the air (combustion reaction), to produce CO2 and H2O, why do we get a bad smell from car exhaust fumes if both gases are odorless? by Protoflare

Combustion is incomplete and you have other trace elements (and not trace - like fuel additives) in the fuel / atmosphere.

There's also a system on your car that pulls gas out of the crankcase and through the engine. It's full of oil vapor and singed fuel that only sorta burns on its way through the combustion chamber / cat.

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4x49ers t1_ja55m7i wrote

Reply to comment by NotTooDeep in Is there any possible relation between the recent earthquakes in Turkey/Syria, Japan and Papua New Guinea? by Corvid-21

I'm thinking of something I learned as task oriented blindness but is apparently really called Inattentional blindness.

>Inattentional blindness or perceptual blindness (rarely called inattentive blindness) occurs when an individual fails to perceive an unexpected stimulus in plain sight, purely as a result of a lack of attention rather than any vision defects or deficits.

To over simplify a bit, they didn't see them because they weren't looking for them. You might have heard of the invisible gorilla test which demonstrates it, and I recall a BBC program where they were testing it as well: they had a pilot fly some people from A to B telling them to keep an eye out for X, I can't recall. Anywhere they flew over Stonehenge on the way there, and no one saw it, then flying the same route back (without being told to look for X) they were surprised to find it along the same path.

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Bsoton_MA t1_ja554yb wrote

Reply to comment by WazWaz in Water on Earth is not Constant. Why ? by ItsDivyamGupta

Your technically right. That Water (H2O) itself is lost. However living things also create water (vapor) to move, grow, think, or do anything really. Also burning things creates water vapor. The vapor will become water eventually.

Furthermore plants also use water to grow. this 5% you are talking about probably refers to the water that plant used to create new cells. This water can eventually become water by burning it.

Also, even if some water is lost forever and never becomes water again. The percentage is small. So small i fact that it does not really matter

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