[hamdani yusuf (OP)]

the ambient temperature is above melting point.

I said in the video, the ambient is at room temperature.

[hamdani yusuf (OP)]

If your convictions are not affected by contradicting evidences, they are not scientific.

This

If heat flows from A to B then by definition A is at a higher temperature than B.
At equilibrium, by definition of "equilibrium", there is no heat flow.

is logic.
If you are not accepting it, you are not doing science.

It's not my job to find the errors in your experiment; that's your responsibility.

Is there any heat flow in melting ice? Is there any temperature difference between water and ice?

[Origin]

Is there any heat flow in melting ice?

Of course!  Why do you think it is melting?

Is there any temperature difference between water and ice?

There can be a difference or the temperature can be the same.

[hamdani yusuf (OP)]

Is there any heat flow in melting ice?

Of course!  Why do you think it is melting?

Is there any temperature difference between water and ice?

There can be a difference or the temperature can be the same.

So, heat flow can occur without temperature difference?

[alancalverd]

For the last time, no. By definition, not experiment.

[hamdani yusuf (OP)]

For the last time, no. By definition, not experiment.

Then there's temperature difference between water and ice while melting.

[alancalverd]

If there is no temperature difference, no heat can flow from the water to the ice, so the ice will not melt if the water is pure.

HOWEVER  water below 0°C will indeed melt ice if the water contains almost any soluble impurity, which is how we clear snow and ice by spraying with salt, and why icebergs melt in the arctic sea (about -2°C). Domestic tap water contains all sorts of solutes.

Yet again: heat experiments are very difficult. Particularly if they involve liquids, and most particularly if the liquids display anomalous convection - water being the most obvious. Gases and solids are relatively well-behaved but still tricky.

[Origin]

So, heat flow can occur without temperature difference?

No.  Why would you ask such an absurd question?  If the ice is melting the there is obviously a temperature difference between the water and the ice.

[Origin]

Then there's temperature difference between water and ice while melting.

See that wasn't difficult, it only took 345 posts.

[hamdani yusuf (OP)]

At 5:04 you say "the difference can only be explained by..."
and that's wrong.
You are assuming that the water in the two outside compartments is all kept at 0C.
But it won't be.

Of course it won't. A tripple dot won't explain anything.

[hamdani yusuf (OP)]

So, heat flow can occur without temperature difference?

No.  Why would you ask such an absurd question?  If the ice is melting the there is obviously a temperature difference between the water and the ice.

Then why did you write this?

There can be a difference or the temperature can be the same.

[Origin]

Is there any temperature difference between water and ice?

I didn't realize this was in relation to melting ice.  The answer is that the water temperature is higher than the ice.  That is why the ice melts, it is really not that complicated.

[hamdani yusuf (OP)]

Then there's temperature difference between water and ice while melting.

See that wasn't difficult, it only took 345 posts.

If I didn't publish my experimental result, you would still be thinking that there's no significant difference between compartment 1 and 3, because you think that there would be no heat flow to compartment 2 from them.

[hamdani yusuf (OP)]

Is there any temperature difference between water and ice?

I didn't realize this was in relation to melting ice.  The answer is that the water temperature is higher than the ice.  That is why the ice melts, it is really not that complicated.

Now you are contradicting BC, instead of me.

Here's how they did it a few hundred years ago.
https://www.nature.com/scitable/content/ice-calorimeter-developed-by-lavoisier-and-laplace-14898943/

It doesn't show that the ice and water are at exactly the same temperature at every point.

It does; it's just that you don't understand it.
If you have ice and water at equilibrium, in a closed vessel surrounded by ice and water, what other temperature can it be apart from 0C?
Consider the following before you answer.
(1) That if you add heat to the system, you won't change the temperature, you will just met some ice.
(2) That if you remove heat from the system, you won't reduce the temperature, you will just freeze some water
(3) Since the ice and water inside the container is at the same temperature as the ice and water outside it, there is no temperature gradient across the container wall, and therefore no heat transfer.

So, if there was a transfer of heat, the temperature wouldn't change, and there's no mechanism for a transfer of heat anyway.

[Bored chemist]

Now you are contradicting BC, instead of me.

Not really.
There's a difference between (mixed) ice and water - which will maintain 0C and water with a single ice cube floating in it.

But, in any event, I explained your experimental result" - it arose from poor experimental design.

Do you accept that?

[hamdani yusuf (OP)]

You are assuming that the water in the two outside compartments is all kept at 0C.
But it won't be.
The water at the bottom will warm up to 4C or so (the temperature of maximum density.)
How thick the layer of relatively warm water is will depend on how well lagged the container is.
But, in one case, the water is not only being cooled by the ice cube, it is being cooled by all the ice in the centre container.
That's why the ice which is cooled by heat transfer through the aluminium stays cooler than the ice which is insulated from that big supply of ice.

I've raised the conern previously, which you confidently dismissed.

Convection will make temperature of the bath more uniform around 0C.

No. Convection requires a temperature gradient.

That's what I found as experimental results. Ice-water mixture don't maintain homogeneous temperature. Difference in density tends to make bottom part of the bath warmer than the surface.

The temperature gradient will form naturally through buoyancy.

No it will not.
Because, if all the water is at 0 C then it all has the same density and there can not be a gradient.

Why don't you understand that?

[Bored chemist]

So, you don't know what "if" means.

if all the water is at 0 C

The point remains; if you have a temperature gradient, you don't have ice and water in equilibrium (and it's also not the conditions you specify in the title of the thread).

[alancalverd]

Oh dear.Time to bring in some very elementary school physics.

As I mentioned in a previous post, doing precise heat experiments with liquids is always difficult and among the "simple" liquids, water is particularly so because of its anomalous convection near the freezing point.

When we do near-equilibrium measurements with liquids, we like to use a very large volume so that heat transfer across the surfaces is minimised in comparison with the heat capacity of the experimental fluid, then make our measurements near the centre. Then you can either leave it alone for a very long time to settle any swirling current (I recently detected swirl currents in a 40 liter sphere, an hour after we moved it just 1 meter into an MRI unit, and we always allowed 50-liter water calorimeters to settle for at least 12 hours before using them to measure radiation dose) OR use a paddle stirrer to induce sufficiently random turbulence that an average measurement has some validity (but remember to allow for the energy introduced by the paddle).

Getting an ice-water mixture to anything like equilibrium in practice requires constant stirring in three dimensions as you slowly cool the sample into a homogeneous slush. It is not for the faint-hearted or anyone with less than a year, a decent workshop,  and a few thousand dollars to spend on getting it right.   

Which is why we have textbooks written by well-funded national laboratories, to tell us the answer.

[Origin]

Now you are contradicting BC, instead of me.

Nope, there is no contradiction.  Water and ice in equilibrium will both be at 0C.  A container with ice melting in water is not in equilibrium and so the temperature of the ice and water are not both exactly 0C, the water will be slightly warmer.  If there was no difference in temperature there would be no heat transfer.
 

If I didn't publish my experimental result, you would still be thinking that there's no significant difference

Do you actually believe that your experiment yielded any useful information?  Let me assure you it did not.

[hamdani yusuf (OP)]

So, you don't know what "if" means.

if all the water is at 0 C

The point remains; if you have a temperature gradient, you don't have ice and water in equilibrium (and it's also not the conditions you specify in the title of the thread).

Initially, they are at 0° C.
My experiment gives evidence that water-ice mixture can't maintain the temperature equilibrium, even when heat transfer with the environment has been significantly reduced.

It's not as easy as you thought it would be.

Not really. Get some ice, a little below freezing , put it in a closed container and put that in a slurry of crushed ice and water.
It will warm up to exactly 0C
Get some water, just above freezing, Seal it in a container and put it in a slurry of ice and water, it will cool down to exactly 0C.

What's hard is getting the left compartment filled with pure ice while the right compartment contains pure water. We will need to maintain air temperature at 0°C, so is the tools we use to transport the water and ice. The lighting  should also be taken into account, as well as body temperature of the experimenter.

It is easy.
You do everything in a tank of ice cold water.