Water Content of Plastic and Everything Else On Earth

[Notmyrealnam]

My seven-year-old says, "There's water in everything, right, even in the desert sands? Is there water in this plastic? In this cookie? In your glasses?"

I said yes to desert sands; I don't think so to the plastic cookie box; yes to the cookie; and eyeglasses are actually plastic, too.

Am I right about the plastic? Please elucidate.

[Hamish]

It depends what you mean about 'in'. Most common materials will have a thin layer of water on it, or a small amount of water in it, even plastic and glass, petrol and desert sand. The amounts however will be very small. Even anhydrous petrol (for doing chemical reactions in) may contain 0.00001 wt% of water. Not much but it is there. Some things react with water and therefore you might consider them to not conain water - ie freshly cut sodium metal will react to form the hydroxide and hydrogen. Infact removing water and keeping it out of chemical reactions can be a big problem as some reactions are very sensative to water (and other things).

[Notmyrealnam]

I think that the statement my son heard on TV was: "Everything on Earth contains water, even the desert sands." (I didn't hear it, but it sounds to me like that's the statement that was made.) Does that seem like a reasonable thing to say, or does it seem like an oversimplification for TV? Maybe what was meant is natural materials. Is there any naturally-ocurring material that doesn't contain any water at all? I understand what they were trying to get at with the "desert sands" part - even if sand looks dry, it contains water (I think "contains" here means: on the surface of each grain). And something like sandstone absorbs water. But how about, for example, a chunk of quartz? I'm asking this because I think what you mean by "freshly cut sodium metal" is something manufactured. Is that right? Thanks for your help - I'll tell my son what you've said so far.

[drestie]

Just found this: http://www.lucinda.net/k6science/water/w_q_a/e arth.html
Hope it is of some help!
-E

[Hamish]

I would agree with the statement as applied to any natrual thing (on earth). ie not sure about moon dust etc.

[mibn2cweus]

Why there�s even water in my dictionary; I looked it up!

It�s Monday!

[madhuparc]

yes
if you look at the question in a chemical way there is no H2O in plastic's chemical name. It is just a hydrocarbon

[Notmyrealnam]

Thanks so much, everybody, for your help! My son didn't want to hear all of your answers read aloud, but I did summarize them, and he seemed satisfied. (But he now says he definitely did NOT hear the thing about the "desert sands" on TV - he insists he thought of it himself.) A friend has asked a followup question about plastic and water, which I'll post separately.