Which freezes faster, hot or cold water. A Science Experiment from Mr. Herbert

1965Richie Says:

Apr 3, 2011 - Correction. You couldn't do tat in England cos it's always raining!

SGTBrian1 Says:

Apr 13, 2011 - Damn winter is over and i wanted to do this -__-

MultiTobbe123 Says:

May 4, 2011 - How come that doesn't work here in Mexico? We can make hot water here to

megapaulie Says:

May 26, 2011 - boiled the water to boiling temperature? No shit

SuperEnigmation Says:

Jul 1, 2011 - @harristhegreat1 I bet someone asked @NightFlyyer what the Mpemba effect is without reading the description.

SuperSkying Says:

Jul 13, 2011 - the Mpemba Effect..

sk8449 Says:

Jul 24, 2011 - Pretty much everyone in canada tried this and it works

MilanKarakas Says:

Aug 18, 2011 - @lHustonProductionsl In which container material you hold cold and hot water? It _does_ matter!Use far infrared transparent material, and hot water will freeze much faster. Thrown water has no container at all, so it loses all heat by thermal radiation in far infrared spectra (4-15 um). Glass is transparent to the IR only up to 2 micrometer, so it is not so transparent for longer wavelength. Use HDPE, or PP container (plastic) that is pretty transparent to such wavelengths.

MilanKarakas Says:

Aug 18, 2011 - Very good experiment that make proof of Mpeba effect.Many people are confused when tried to freeze water in a glass containers - it did not freeze faster when water is hot. It is simply because far IR (thermal radiation) is prevented by non-transparent properties of the glass for long wavelengths.Glass is transparent up to 2 um (mirco-meters) or so. But most of the plastics _are_ transparent to longer wavelengths. It just radiate all stored thermal energy out faster than cold water.

deluxes000 Says:

Oct 2, 2011 - you are wrong when we want to have a accuracy result we must have a controll variable. A control variable is a factor that must stay the same throught out the experiment.

MilanKarakas Says:

Oct 3, 2011 - Maybe.One thing is not clear to me. Do original discovery by Mpemba include modern refrigerator as we use today, or he do cooling by other means (ice bath + kitchen salt)? Any original document out there? This may be much different.In modern refrigerator, contact surface is poor, and evaporates (water vapor) from hot water first ruin cold surrounding (air inside chamber) by turning it bit warmer. So whole process of freezing may take too long - and effect is not the same.

deluxes000 Says:

Oct 3, 2011 - it depends on the freezer and it age dont it ? because then my physic teacher said some freezer have low freezing speed but as long as we start to put the two tray of water in the same time it might took longer but same result

GloryRave1 Says:

Oct 20, 2011 - You people obviously have never been/lived in Canada in the winter, have you?-15 F is like a crisp warm breeze autumn day for us.

GeertNool Says:

Dec 1, 2011 - Due to evaporation hot water cools down faster, but this is only when you throw it up. When you put 2 liquids lets say 60degrees celcius and 30 degrees celcius in the freezer, the hot water glass will devide into a cold and hot part due to slightly different density, this allows the hotter water on top to cool down faster. If this cools down fast enough to catch up with the colder water you are witnessing the Mpemba effect. This will only happen under certain controlled circumstances

tblbaby Says:

Dec 12, 2011 - The reason water tossed in the air freezes hot water is because it's less dense & cold air gets to the molecules faster.Contained, cold water freezes much faster because the hot water cools down without exposing all the expanded molecules to the cold.

Adrian4life22 Says:

Dec 15, 2011 - For all the people who say that the Mpemba Effect is not real do one things, explain why its impossible.

ImJussaBeast Says:

Dec 22, 2011 - The hot water expanda quicker in the air and there is thus more surface area for the air to interact with thus freezing the water faster.

jasperexploration Says:

Feb 6, 2012 - Mpemba effect? NO.What you see here is water cooling with lots of surface area vs water cooling with a small amount of surface area. The hot water disperses through the air faster because it has lower surface tension and is somewhat expanded due to the temperature. Simply said: tiny droplets freeze faster then a big clump of water.A correct demonstration of the Mpemba effect should be done without throwing the solution in the air. I doubt you would see it happening.

difficultjuggernaut Says:

Feb 8, 2012 - youre genious man o.0

ChaseParkison Says:

Feb 10, 2012 - This is not a true Mpemba Effect for a couple of reasons. But hot water DOES freeze faster than cold water under some conditions. I personally have tested it myself in my own freezer and have gotten positive Mpembe results. dont think its possible? try it.... a little bit of science is good for the brain.

TheTimeRanger1 Says:

Apr 13, 2012 - Obviously cold water! Stop talking about surface area and everything, the truth is cold water is already cold and doesn't need as much time to freeze because the warm water needs more time to get cold.

TheTimeRanger1 Says:

Apr 13, 2012 - Oh. Maybe it does work. I didn't watch this when I made that post. But if you freeze it in a freezer cold water will freeze faster. But if you throw it it gets frozen if its hot. I'm gonna try this as soon as it gets really cold again. Unfortunately, it's April, and it's not going to be cold again for 8 months.

loveforevexoxo Says:

Apr 21, 2012 - cool :)

AndKarolSaid Says:

May 20, 2012 - A+ 

nflprospect2017 Says:

May 28, 2012 - this is really neat