UKC

Beware about using boiled water in bottles unless they are insulated. Any plumber knows that boiler water freezes quicker than water that has not been boiled. The reason is that boiling reduces oxygen content of water and so it freezes quicker. Obviously, if the boiled water is kept in some thermal, insulated bottle or flask this observation will be irrelevant.

Just wrap your mitts and belay jacket around it, problem solved.

I thought that theory had been disproved?

https://en.m.wikipedia.org/wiki/Mpemba_effect

See the 'modern experimental work'.

I'm waiting for the other 11...

In fact even your first one isn't that much use. Why would you boil water, pour it into say a nalgene bottle, and then leave it to freeze? Surely the most obvious use for that bottle would be as a hot water bottle inside your sleeping bag?

If you are boiling to sterilize water, why not just boil it in the morning and make tea/porridge with that hot water?

That's a fabulous link on a subject I wasn't previously aware of...cheers! 

https://www.ukclimbing.com/forums/ukc/12_tips_and_tricks_to_stay_warm_outdo...

The generalisation that people make from it, that hot water will always freeze faster than cold water is definitely wrong.  I don't believe for a moment that hot water in a sealed nalgene bottle will freeze sooner than cold water would in the same bottle under the same circumstances, not on your nelly.

That said though, I occasionally work in ice rinks and know a few people whose job it is to look after the ice there.  I couldn't guarantee that there isn't confirmation bias or somesuch going on, but they definitely believe in the Mpemba Effect.  Albeit in very different circumstances.

The Zamboni smooths out the ice by planing its surface and then adding a thin layer of fresh water behind it as it goes.  It generally cuts off more ice than it replaces, so the ice also has to regularly be built up again by 'flooding' the rink when there is time for fresh water to freeze.  Sometimes time is tight, especially in arenas like Sheffield and Nottingham where the ice is boarded over for concerts and then has to be uncovered, cleaned up, flooded and cut several times to be ready for an ice hockey match the following day.

When 'flooding' the ice, it's standard practice for the hose to go on the hot tap rather than the cold.  The people who do the job are convinced it freezes faster that way and unlike plumbers they do actually watch it freeze, sometimes whilst anxiously checking their watch because they're working to a deadline.

V different circumstances though obviously, because the hot water is being spread out into a huge flat puddle (60x30m and only a few mm deep) with existing ice underneath at about -10°C and dry air above for some of the hot water to evaporate into.

I was mainly being sarcy about people who don't seem to notice the "comment" button at the bottom of the article page!

I wonder whether flooding with hot water causes a better bonding to the substrate ice, by partial melting.

For them to know it freezes quicker, they would have to have compared it with the cold tap...

I don't think that's an issue - if you pour cold water onto ice you get solid ice anyway.  I wouldn't like to guess what would happen if you poured on super-cooled water that would freeze instantly but tap water is always well above freezing, even in the depths of winter.

In the case of the one guy, he's definitely done at least that much.  We had a conversation about it a couple of years ago - he had recently taken the job over from a colleague who retired and said he had always been a bit sceptical, so tried it with cold water and convinced himself that his predecessor was right after all.

There definitely won't have been much in the way of experimentation beyond that though, and certainly no controls for different temperatures of 'cold' water, air temperature, atmospheric conditions etc.  Also the job is probably a lot more pleasant using hot water, because it makes the 80m-odd hosepipe nice and flexible and warm to handle, so there's probably quite a strong incentive there to reach a certain conclusion too.