two kettles (identical)

one pre boiled

one unboiled

both now at the same starting temperature

which boils first?

What type of water do you start with?

pre boiled?

Must be the pre boiled as you’ll have boiled away some of the impurities that can raise the temp needed to boil it.

Ah but if it’s hard water, those impurities may have collected on the element reducing it’s heat transfer rate.

42
or
both the same

is one on a conveyor belt?

preboiled.

I was thinking the opposite, boiled away some of the water raising concentration of any impurities so raising boiling point.

The pre-boiled one will probably boil first, as some of the water will have already been lost as steam during the previous boiling.

Must be the pre boiled as you’ll have boiled away some of the impurities that can raise the temp needed to boil it.

Boil a pan of salt water and it gets saltier not less salty, you boil away the steam (which is pure water vapour) and so any impurities are concentrated….

:EDIT: too slow,

OK alternative hypothesis (after Rupert Sheldrake) – the preboiled water carries the morphic resonance of having been boiled, so next time you turn on the kettle it boils faster 😯

are they at the same altitude?

Just twigged. It’s the pre-boiled one, because you’ve already boiled away some of the water, so there’s less to heat 😀

is the water chilled?

The kettle that you switch on 1st.

I don’t know but I do know every few months Mr Nutt cannot be trusted.

All I am going to say is

Religion and Faith and finding God
&
Somebody is taking over my Allotment

This has potential

That’s a good point. Is one of the kettles Jewish?

Won’t they be equally different?

Is one kettle filled with Holy Water, or the tears of the Babyjeesus ??

Neither. You haven’t turned the kettles on yet.

Do I win a prize? 8)

The unboiled one as it contains more dissolved gasses which will vaporise more readily giving the outward appearance of boiling. (of course you’ve taken some of the unboiled water out so that the mass in each kettle is the same?)

The black one.

this is very interesting, but without a correctly designed R&R study i don’t think we can accept Mr Nutt’s findings as conclusive…

Water is one of the hardest chemicals to heat up (as in it takes the most energy per kg per change in degree).

So assuming you’ve got the same quantities, it would be the one that’s the least pure which would get to 100 degrees (assuming that’s what you mean by boiling).

Unless water gets contaminated by the first boil, I would guess that water becomes more pure when you boil it, but not really sure why, unless some of the impurities escape as a gas, which seems a little unlikely.

Probably not a lot of difference in it, but theoretically, I’d say pre-boiled.

“it depends”

you disappoint, no one has yet to ask if its single, three phase or off grid. yet…

Are they both plugged in??

Are they both plugged in??

Well the water will evaporate eventually regardless…

It is the pre-boiled one that boils faster. As oliverd said – the pre-boiled one has been de-gassed in the first boil. This makes it slightly easier to boil second time round, as water with dissolved gas molecules in it requires more energy to degas and reach boiling point.

The pre boiled one will have a higher concentration of impurities, and thus boil at a higher temperature / later (assuming the kettles aren’t filled with distilled water to start with).

Although if you started with the same amount of water and then ‘pre-boiled’ one, that one would then have less water, so maybe not….

Then again, something weird might happen, like this:

http://en.wikipedia.org/wiki/Mpemba_effect

The one you aren’t watching…..the one you watch will never boil.

Rorschach, you are the winner!

The soluble carbonates in hard water turn into insoluble ones by the action of heat, so you get limescale coming out of solution. So I suppose pre-boiled water could have a lower concentration of ions. This I suppose would.. raise the boiling point? But then again the particles of scale in the water could act as concentration centres for the bubbles.. hmm..

But I suspect this is a smart arse trick question.

Water is one of the hardest chemicals to heat up (as in it takes the most energy per kg per change in degree).

So assuming you’ve got the same quantities, it would be the one that’s the least pure which would get to 100 degrees (assuming that’s what you mean by boiling).

If lots of things are easier to boil than water than why would making it more pure make it easier to boil? As eluded to earlier many of the impurities in “normal” water are dissolved gases which evlove readilly from soultion when heated.

Also boiling doesn’t just refer to the heating of liquid to 100DegC, but the energy required to take water at 100DegC to the Gaseous phase.

The one with the least water in it .

African or European kettles?

the difference will not be significantly different over multiple blind trials with equal volumes and swapping contents.

OP, do you know the answer or not? the suspense is killing me!

yes, but it depends on what side of the fence the kettle is.

MrNutt, you’re taking the p*ss now!

If lots of things are easier to boil than water than why would making it more pure make it easier to boil? As eluded to earlier many of the impurities in “normal” water are dissolved gases which evlove readilly from soultion when heated.

Don’t think you read my post properly.

Also boiling doesn’t just refer to the heating of liquid to 100DegC, but the energy required to take water at 100DegC to the Gaseous phase.

pffft.