Originally Posted By: Michaela
DS3 demanded to know why people can drown in water when it has oxygen in it. I explained lungs and gills a bit, but it was hairy, I don't really "get" this stuff yet chem still escapes me, generally. [...]

DS: "Mama, how do[es] water put out fire if it has oxygen in it?"

Mama: crash. and. burn.

I never even thought about that.

So, I guess I'm bragging that my three year old broke me before breakfast hit the table wink

Lol, donchajustlove conversations like that that go into areas you're not comfortable with? Our last one was about the European debt crisis and what money really is... I know I read a book once about M0 and M1 and so on, but I definitely wasn't comfortable trying to explain it to DS and he wasn't letting go!

I can answer yours, though, in case you haven't looked it up since! Fish etc. breathing through gills is nothing to do with the oxygen that's chemically in the water as H2O - that stays right where it is. The fish are breathing the gaseous oxygen (from the air and from plants) that is dissolved in the water, which is an unrelated thing. This is why fish die if something happens that means the water no longer carries the usual amount of dissolved oxygen, e.g., it's why if you keep fish you need to either have water plants in the tank with them or aerate the water. Similarly, water doesn't dissociate into hydrogen and oxygen because of heat alone, so it doesn't do so when you use it to put out a fire. I bet your DS would enjoy seeing an electrolysis experiment some time soon, though...

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