Ask Science
Ask a science question, get a science answer.
Community Rules
Rule 1: Be respectful and inclusive.
Treat others with respect, and maintain a positive atmosphere.
Rule 2: No harassment, hate speech, bigotry, or trolling.
Avoid any form of harassment, hate speech, bigotry, or offensive behavior.
Rule 3: Engage in constructive discussions.
Contribute to meaningful and constructive discussions that enhance scientific understanding.
Rule 4: No AI-generated answers.
Strictly prohibit the use of AI-generated answers. Providing answers generated by AI systems is not allowed and may result in a ban.
Rule 5: Follow guidelines and moderators' instructions.
Adhere to community guidelines and comply with instructions given by moderators.
Rule 6: Use appropriate language and tone.
Communicate using suitable language and maintain a professional and respectful tone.
Rule 7: Report violations.
Report any violations of the community rules to the moderators for appropriate action.
Rule 8: Foster a continuous learning environment.
Encourage a continuous learning environment where members can share knowledge and engage in scientific discussions.
Rule 9: Source required for answers.
Provide credible sources for answers. Failure to include a source may result in the removal of the answer to ensure information reliability.
By adhering to these rules, we create a welcoming and informative environment where science-related questions receive accurate and credible answers. Thank you for your cooperation in making the Ask Science community a valuable resource for scientific knowledge.
We retain the discretion to modify the rules as we deem necessary.
view the rest of the comments
Not by adding the hot water to the cold.
But if you can use the hot water to heat up the cold water a little bit, that can help. That would mean bringing them into thermal contact but not allowing them to mix.
Bonus question. What will freeze faster: a cup of 100 ml hot water or 100 ml cold water? Both are uncovered.
Oh no, not the ~~mbappe~~ Mpemba effect effect. I refuse to accept that as a real thing, there is just no way the warm water freezes faster. I've read dozens of articles about it, eventually finding some that confirmed for me it's probably just measuring error or subtle differences that aren't being noticed. But that left me thinking if I had to search so hard for the one article that confirms my gut instinct I shouldn't lean into it too hard
Like you have two cups of identical water, eventually the warm water becomes the cold water. If I then use that previously warm water as my cold water and start the experiment over with another glass of warm water, what now? And don't tell me water has memory.
My favorite explanation is imagine two cars on a track 100 meters long. The far end is the track is hard asphalt and cars can drive fast. The track gets rougher and muddier the closer you are to the finish line, so the first 50 meters are covered in seconds, the next 25 meters are slower, and the final 5 meters the cars are crawling. You start one car at the 100 meter line and one starts at 10 meters. If you're observing this race from the top of a 50 storey building above the track, you'd understandably think "wow, that car that started far away was so much faster! For sure it won" even though in the last few feet it was neck-and-neck.
The reason the hot one freezes first is because the hot one evaporates more, thereby lowering it's mass. The amount of energy that must be removed from water to cool it is small compared to the amount of energy to freeze the water. Therefore, the mass of the water that freezes determines the total energy much more strongly than the starting temperature.
Actually, it doesnt exist.
Previous experiments accounted for evaporation by using sealed containers, and still observed mpemba phenominon.
A recent-ish study managed to control factors for all the proposed reasons of the mpemba phenominon, and found no difference between freezing cold and hot water.
They found the location of the temperature probe to be more of a factor than anything else.
https://youtu.be/SkH2iX0rx8U
Essentially, any observations of this can be accounted for by margins of error.
So in isolation, hot water does not freeze faster than cold water.
Any observation of this are from environmental effects (extra nucleation sites in the water, different freezing conditions etc).
So the laws of thermodynamics still hold.
However, what these environmental factors are and how they contribute arent yet understood.
Thanks for the video. As it notes, the observations are real, but the explanation may not be known.
However, preventing the evaporation and then finding that the process does not occur kind of proves the evaporation theory, so I'm not sure that point works the way that you or Derek claim it does, unless I'm misunderstanding.
Lastly, I'm not claiming nor do I believe that there is some mystical way of violating the laws of thermo. I'm claiming that when the mass of water is reduced that the total latent heat is also reduced; that is completely consistent with thermo.
That's what I'm talking about! That's for digging that up. It just never passed the smell test for me, I always called bs
You read dozens of articles and aren't even close to spelling his name right?
You just cut his name into a thousand pieces and there's blood everywhere.
Ahhh damn! I was about to board a plane and didn't bother googling it, mixed him up with the footballer
I had a chuckle thinking about the mbappe effect being researched by Hanson, Hanson, and Hanson.