What is your explanation for the Mpemba effect?

Im no scientist, but i can tell you that my hot water line freezes before my cold water line in a particular area of my home. Mind you, the hot water line no longer contains hot water at that point. I was always under the impression that this was the result of dissolved oxygen concentration, and thats why the effect can be variable, in my situation, the water is derived from a highly oxygenated artesian well, and i would surmise that the water coming from the water heater loses some of its dissolved oxygen during the heating process.
Maybe i have no idea what im talking about either

i bet his freeezer was configured like yours. Its standard.

a reply to: Arbitrageur

a reply to: charlyv If the supercooling explanation for the mpemba effect is correct, it seems to me that conducting the experiment outside where there are potentially a lot of airborne particles that could trigger the freezing when they hit the water may greatly reduce your chances of getting supercooling, unless you use sealed containers as has been done in some experiments.

I agree, the experiment was just not scientific enough and your analysis may be correct. It was off the cuff and needs a real controlled experiment like you suggest. May do it , when time permits. I remember my Dad always saying to fill the ice cube trays with warm water when I was a kid. We did it faithfully, but of course, no control to see if it really mattered. The freezer has that caveat where the machine tries to make itself colder to compensate for a loss in ambient temp, so conducting the experiment with both scenarios, as you suggest, would be much better science. Thanks!

a reply to: HiddenWaters

That is a great point as well. This occurs in my house when temps get in the teens. The shower pipes are on the outside wall and the hot definitively freezes before the cold. Could be that the cold is used in the bathroom more than the hot, so does not sit for longer spells, but what you suggest is very reasonable.

I bet if you de-gas the water, you'll get the same rates of freezing.

Hot water tends to have less dissolved gas than cold water. Solutes cause freezing point depression. So cold water should freeze at a bit lower temperature

originally posted by: Bedlam
I bet if you de-gas the water, you'll get the same rates of freezing.

Hot water tends to have less dissolved gas than cold water. Solutes cause freezing point depression. So cold water should freeze at a bit lower temperature

That certainly makes scientific sense. Could be the top reason retaining other factors as well.

Years ago a lady friend of mine told me that under no circumstances should I place food that is hot or for that matter warn a refrigerator for storage. I needed to wait until it reached room temperature, otherwise the food will spoil is a way that makes it less edible that the alternative.

a reply to: Kashai

Nope. You're making a nice nest for bacteria by doing so, actually. You want to get it below 40ºF as soon as you can.

a reply to: Phage


Roughly speaking it takes about an hour and I do notice a change in the flavor for the better but clearly that is a subjective response. In so far as the issue of bacteria I always seal the product is plastic which would contain the heat and perhaps cook it more to some extent.

It's a pity that there is " variable " unaccounted for .

If I was experimenting with mpemba effect ; i sure would take the sound of the enviroments and the vibration , frequency and the resonance values into account.

Crystalisation process is most likely to be influnced by the presence of sound waves .

One ought to afford oneselfself a little presumptive stand of " form follows function ".

Meh , this looks like Synergy Manifestation ; does it walk , talk and squeak like one too I wonder ?

originally posted by: Bedlam
I bet if you de-gas the water, you'll get the same rates of freezing.

Hot water tends to have less dissolved gas than cold water. Solutes cause freezing point depression. So cold water should freeze at a bit lower temperature

I think that's one of the variables, but I'm not sure all the variables are understood based on this researcher's findings:

A search for the Mpemba effect: When hot water freezes faster then cold water

The probability that the hot water will freeze first if it has the higher spontaneous freezing temperature will be larger for a larger difference in spontaneous freezing temperature. Heating the water may lower, raise or not change the spontaneous freezing temperature.

If it's true that "Heating the water may lower, raise or not change the spontaneous freezing temperature", as that paper suggests, that sounds inconsistent, perhaps suggesting multiple variables.

originally posted by: Kashai
a reply to: Phage
Roughly speaking it takes about an hour and I do notice a change in the flavor for the better but clearly that is a subjective response. In so far as the issue of bacteria I always seal the product is plastic which would contain the heat and perhaps cook it more to some extent.

Off-topic but since food safety is important and I think the public is probably under-educated in this area I'll allow a limited thread tangent in this direction. You have to keep it over something like 145 degrees F, to prevent bacteria growth and continue cooling. Anything below 141 degrees F and you're growing bacteria. Lots of people get what they think is a 24 hours bug or something and don't even realize it's from improper food storage. You're supposed to keep food out of the danger zone and it sounds like you're keeping it in the danger zone, and I've never noticed any taste difference in food put into the refrigerator warmer versus cooler, upon re-heating to the same temperature. Of course warmer foods may have more flavor than cooler foods due to higher chemical activity in warmer foods so that's not a fair test. You'd have to test them after re-heating and to make it fair someone would need to blind the taste test for you so you didn't know which one you were tasting when you made your judgement.

Safe Food Handling Tips

Cool food by using shallow containers, so that it cools quickly. Discard any food left out for more than two hours. On hot summer days, don't keep food at room temperature for more than one hour. Remember to keep food out of the temperature danger zone of 4°C to 60°C (40°F to 140°F). When in doubt, throw it out!

Ok so literally I do not allow the food to stay at room temperature for more than an hour as I understand that part.

Hello friends,

There are several videos floating around the internet of people in very cold places, like the Arctic, throwing hot and cold water into the air. In some videos the hot water will turn to snow / ice before it hits the ground, but the cold water will just fall to the ground. So the Mpemba Effect is real.

I will tell you why it happens, but I am going to explain it using an alternative scientific paradigm. It can be translated to the paradigm you are familiar with, but not with similar ease.

First and foremost I must explain that I will be using the term "magnet" and or "magnetic" because it makes explaining this new paradigm easier. In the new paradigm there is only two fundamental forces; attraction and repulsion. However I normally try not to refer to it as "magnetism" because it invokes a lot of outdated knowledge from the old paradigm. Even then, these two forces closely relate to "magnetism" in the old paradigm, so I will use that term for now.

So I begin...

Everything is made of tiny magnets. Electrons are tiny magnets, and protons are tiny magnets. Now imagine an electron orbiting a proton at near light speed. A tiny magnet orbiting a slightly larger magnet at incredible speeds together both combine to make a larger magnet with a constantly changing magnetic axis. Now try to imagine the magnetic field this electron and proton create over a period of time. You could imagine that the magnetic axis is pointing all random and different directions very quickly. You might as well consider the electron and proton as a single sphere magnet with an outer shell one polarity (North) and the core another polarity (South) creating and inward / outward attraction and repulsion in all directions.

When you speed the electron up so that it orbits the proton faster (heat up the atom) it increases the number of directions the magnetic axis can point over a unit of time.

When you slow the electron down so it orbits slower (cool down the atom) it reduces the number of possible directions the magnetic axis can point over a unit of time.

When the magnetic axes of two atoms align (opposites attract, likes repel) the electrons spend a little more time in the locations that support the alignment, but still continue to orbit. If the electron is orbiting faster, it spends a little less time in the alignment compared to when the electron is orbiting slower. But at any rate, the electron still spends more time in alignment than it does out of alignment. This causes the atoms to align themselves in such a manner that supports crystallization (ice).

When you quickly reduce the temperature of these atoms (slow down the electron's orbit as fast as possible) the chances of the magnetic axes of multiple atoms being aligned is higher when the atoms start hot, and lower when the atoms start cold. When the chances of alignment are higher (hot), it increases the possibility and rate of crystallization. Lower chances of alignment (cold) equates to a slower rate of crystallization. That is because the magnetic axes of the colder atoms take a little longer to find a position that is in alignment with neighboring atoms which also are taking longer to find alignment.

That is why hot water crystallizes faster than colder water.

With that you may also explain a large number of other scientific phenomena.

Good Day

a reply to: Arbitrageur

The answer is because heat will rush into cold...
Which makes your mom and dad wrong everytime they told you to close the door because you were letting the cold in...
Because in reality you were letting the heat out...
It just so happens that a convection cell is created because of the doorway further speeding the cooling process...
More1thanany1 has given a good explaination its a truth which is evident in most everything like weather and currents for example...

originally posted by: More1ThanAny1
I will tell you why it happens, but I am going to explain it using an alternative scientific paradigm.

"proven wrong" can't accurately be called "alternative".

Now imagine an electron orbiting a proton at near light speed. ...

104 years ago Niels Bohr introduced his model of the atom with this characteristic so a century ago this was an interesting hypothesis, which by 1925 had been proven wrong, hence today it's "wrong" science not "alternative" science.

When you speed the electron up so that it orbits the proton faster (heat up the atom) it increases the number of directions the magnetic axis can point over a unit of time.

Heating up the atom doesn't speed up the orbit since the electron can't be orbiting the nucleus.

Students of physics are asked to calculate how long an electron would be able to orbit a nucleus before the orbit would decay due to the energy given off by the orbiting electron. If you ever do this calculation yourself you'll find out that the time calculated is not very long. Here is the problem presented at Princeton, with the answer key, and note the solution to equation 8 after the numerical substitutions are made:

Classical Lifetime of a Bohr Atom

After equation 8, relativistic corrections are applied which actually make the problem worse.

a reply to: 5StarOracle
Yes, convection was one of the possible contributing factors mentioned in the video in the opening post, so you were doing OK until you said "More1thanany1 has given a good explaination[sic]" since that model of the atom was proven wrong 92 years ago.

a reply to: Arbitrageur

My friend,

My use of the term "orbit" was a simplified description of an "electron shell". Can we both agree that the electron forms a shell around the nucleus?

en.wikipedia.org...

Whether or not you want to describe or imagine it as an orbit, or a waveform of possibilities, the same concept applies that at any moment in time the electron can be at an almost random location outside of the nucleus, and form an almost random magnetic axis vector.

With that said... 92 years ago (and even today) the scientific community seems to only be focused on the parts, but not the whole. It is great that they calculated the amount of energy that should be lost from an orbiting electron and eventually decay the orbit, but why don't they calculate the amount of energy being added by the environment? Why are they assuming the atom is in a void without any external electromagnetic radiation (light), magnetism, "gravity", and neighboring atoms that can add or transfer energy back into the atom and support the orbit? It seems a little silly to focus on one part, but not the whole.

originally posted by: More1ThanAny1
a reply to: Arbitrageur

My friend,

My use of the term "orbit" was a simplified description of an "electron shell". Can we both agree that the electron forms a shell around the nucleus?

It's more like electrons are in orbitals, and groups of orbitals form 'shells'.

As to the second part of your statement, magnetism accelerates moving electrons at right angles to their path, so that it causes them to curve. But it doesn't speed them up, which is what you'd need for a Bohr atom. Gravity is so paltry an effect on an electron that it can be ignored, but even if you didn't, it is still not going to accelerate that electron along its path.

The reason that they don't focus on how to make a Bohr atom work is, that it doesn't and these effects don't really give you a way to fix it. The math works for orbitals, observed data works for orbitals, and these days you can image orbitals and there they are, just as predicted. So Bohr remains a dead duck 90 plus years after figuring out that it can't work.

originally posted by: Bedlam
It's more like electrons are in orbitals, and groups of orbitals form 'shells'.

It's all semantics. I am sure we are still in agreement that an electron is found in different positions outside of the nucleus at any given moment in time when you observe it.

I've never claimed the Bohr model was accurate. That was an assumption made by another user because I used the word "orbit".

originally posted by: Bedlam
As to the second part of your statement, magnetism accelerates moving electrons at right angles to their path, so that it causes them to curve. But it doesn't speed them up, which is what you'd need for a Bohr atom.

I think you have much more yet to discover.

Start with the fact that magnets share and combine their magnetic strength when near each other. The closer they are the more they share, and the further they are the less they share. Combine that with the fact that both the proton and electron are both magnets, and the electron is attracted to the proton. Then go from there...

originally posted by: More1ThanAny1
Start with the fact that magnets share and combine their magnetic strength when near each other. The closer they are the more they share, and the further they are the less they share. Combine that with the fact that both the proton and electron are both magnets, and the electron is attracted to the proton. Then go from there...

Electric charge and magnetic fields are very different things, and are not directly interchangeable. Magnetic fields do not attract or repel electrons or protons directly. They affect the trajectory of moving charges.

The electron is not a magnet. The proton has a property called the magnetic moment which will torque the spin axis to align with an external magnetic field, but it's ALSO not attracted to a magnetic pole.

a reply to: Bedlam

I highly disagree. The electron is indeed a magnet. So to is the proton.

This just goes to show how little you know about this subject.