[charles1948]

 These posts are very interesting.  They lead me to wonder: Suppose we think about  so-called "heavy water".

You know what I'm referring to. The water used in nuclear research, such as making the atomic bomb.

How much heavier is it than ordinary water, and if it's frozen, is its ice heavier?
 

[Bored chemist]

How much heavier is it than ordinary water

About 10%, whether it's solid or liquid (or gas, come to that)
"Heavy ice" will sink in ordinary water.

[Petrochemicals]

Depends on what you are holding it in.

[alancalverd]

Now is is true that 1 litre = ~1.057 qt. , and 1 qt = 32 fl oz.

Only in the USA.

A quart is 2 pints (a quarter of a gallon)  wherever you are. But a US pint is 16 fl oz, whilst an Imperial pint is 20 fl oz, which is why the US gallon is 6 Imperial pints but 8 US pints, i.e. 4 quarts. This partially accounts for the poor published fuel consumption of American cars: a British car is 33% more efficient!

[charles1948]

Why is the US so resistant to the metric system.

I think that in the early years of the Space Age, it was because US astronauts might get confused in an emergency.

Such as a meteorite puncturing the thin metal skin of their Mercury, or Gemini space capsule. 

In such a case, the astronauts might radio to ground-control: "Houston, we have a problem. We have a leak. Our oxygen is rapidly venting"

Houston might reply: "Roger, to plug the leak, insert stuffing into the hole.  It's 16 centimetres to the left of switch A on your console"

The astronauts would reply: " Say that again, Houston, what's 16 centimetres  ..... agh ,  we can't breathe......"

[shootrj2003]

A liter of water weighs more than a liter  of ice ,water has a unique property of being less dense in its solid form.I know this but I can’t explain it.but ice floats on water so it’s lighter,this is why they call it a liter.we use inches because it’s American we should endeavor to force the world to accept the inch system on the rest of the world so they would have to buy measuring instruments from the U.S.if you want to rule the world get an Emperor,if you want to rule the universe get a scientist!

[Bored chemist]

water has a unique property of being less dense in its solid form

It's not unique. Tin does the same thing.

it’s lighter,this is why they call it a liter.

No, it's not.
The word litre is derived from ancient Greek.

we use inches because it’s American

Inches aren't American; they are English.
Though the pre-revolutionary French had a similar unit.
https://en.wikipedia.org/wiki/Paris_inch
and I would imagine other countries did too.

we should endeavor to force the world to accept the inch system on the rest of the world

The British pretty nearly did that.
But after a while we realised it was silly, and went Metric.
We are waiting for the Americans to catch up.

[syhprum]

Although the difference between the American and the Europeon gallon causes confusion in the MPG figures there is an actual difference in the efficiency of engines because the low octane rating of the fuel means a lower expansion ratio must be used

[vhfpmr]

Although the difference between the American and the Europeon gallon causes confusion in the MPG figures there is an actual difference in the efficiency of engines because the low octane rating of the fuel means a lower expansion ratio must be used

I once told an American who was gloating about their petrol prices that a US gallon is smaller than Imperial. He didn't like it at all. Don't you know that everything is bigger in America?

[vhfpmr]

"Houston, we have a problem. We have a leak. Our oxygen is rapidly venting"

"Hello, this is NASA Houston here. We are currently experiencing unprecedented call volume, and all our operators are busy. Please be assured that your call is important to us. If you're calling to order a pizza, please press #, otherwise hold the line and your query will be dealt with as soon as possible. You are currently number 46 in the queue."

[Bored chemist]

Although the difference between the American and the Europeon gallon causes confusion in the MPG figures there is an actual difference in the efficiency of engines because the low octane rating of the fuel means a lower expansion ratio must be used

And the Americans measure octane number differently too...

Don't you know that everything is bigger in America?

Would these be the same Americans who think that " A pint's a pound the world around" (and wonder why they can't hold their beer) ?

[alancalverd]

Why is the US so resistant to the metric system.

Because no metric nation has landed a man on the moon, and everyone knows (from hard experience) that altitude should be measured in feet if you want to make a soft landing on Mars. 

[alancalverd]

Inches aren't American; they are English.
Though the pre-revolutionary French had a similar unit.
https://en.wikipedia.org/wiki/Paris_inch

and until 1916 there were two British inches, so artillery shells made in Coventry didn't fit the cartridges made in Woolwich. That said, the metrics still lost the war.

[paul cotter]

B C , I was not aware of differences in octane rating determination. I thought the n-heptane/isooctane standard was universal. Is there also disagreement on the diesel cetane rating? would love to know more on this.

[levanasur]

I guess the answer to this question is slightly open. Water is actually denser than ice at one liter. So I would say water.

[Origin]

Water is actually denser than ice at one liter.

What does that even mean?

[Halc]

Water is actually denser than ice at one liter.

What does that even mean?

It obviously implies that ice might be denser than water at volumes other than a liter. Maybe it's a metric thing where a liter of ice floats but ice is denser than water at a gallon, so a gallon of ice sinks. It sinks to the bottom until melting to a metric volume and then rises back up.

No?

[Origin]

It obviously implies that ice might be denser than water at volumes other than a liter. Maybe it's a metric thing where a liter of ice floats but ice is denser than water at a gallon, so a gallon of ice sinks. It sinks to the bottom until melting to a metric volume and then rises back up.

Wow, this science stuff is confusing! 

[Colin2B]

Maybe it's a metric thing where a liter of ice floats but ice is denser than water at a gallon, so a gallon of ice sinks. It sinks to the bottom until melting to a metric volume and then rises back up.

No?

Probably due to differences between US gallon and imperial. Convert to metric for water using one of those and ice with the other, but only at 1 litre, then you switch for other volumes? No, that can’t be right, I’ve got it the wrong way round, now I’m totally confused. I’ll try using drams to metric, or gills maybe. The answer must be in there somewhere 

[Bored chemist]

Water is actually denser than ice at one liter.

What does that even mean?

I suspect it means the poster forgot to say "1 kg/litre".