Does Hot Water Freeze Faster Than Cold Water?

Observations over millenia and numerous experiments claim that warmer water freezes faster than cold water under identical conditions.
Supported by Google Making & Science #ScienceGoals

References:

Edited by Trevor Carlee

[kenmendoza]

If vsause did this, this would be an hour long video that would include WW2 events.

[spoolers]

"I thought cold water was supposed to boil faster than hot water"

-some hell's kitchen episode

[cyclesingsleep]

So, for practical purposes, the Mpemba effect can seem to happen, but in a severely controlled lab, it doesn't...unless a thermocouple is purposely misplaced...but only because we don't really understand everything that goes into the process of water freezing.
Very clear...

[arooobine]

Mpemba was the ultimate hipster. He froze his ice cream before it was cool.

[Shane]

This man really made me question my intelligence for 6 minutes before he threw in "but oh yeah, this effect doesn't exist"

[renz]

I was recommended this because of that hell's kitchen video

[HostileTakeover]

I always find these kinds of things fascinating. Something so seemingly simple turns out to be far more complicated than we know. And the moment your brain glitches when it suddenly realizes just how amazing something normally taken for granted is, that's an amazing feeling.

[videogyar]

So... is that a no? Or a maybe? Or sometimes?

[Nvrmr_]

You look like that guy from Veritasium

[CaptainRon]

Funny, my wife and I tested this theory this winter (Northern Michigan). We had been talking about hot vs cold freezing for some time ago. We woke up one saturday to find it was -10F (-23C) outside and decided to put two equal glass 2cup measuring cups full of water outside, one hot, one cold. Filled both with tap water, the hottest it would go, and the other with the coldest it would go. Sat them both outside and watched through the window. The cold water cup froze what appeared to be a couple minutes faster. Nothing scientific, just personal observation.

We figured doing the test outside, there would be less chance of being off by the freezer temp slightly rising from hot water, and having to pump to get the freezer temp back. Outside would remove that variable, and any variable of the cup sitting next to another frozen object. Both cups were in the shade, and about 3ft apart from each other.

[swedneck]

Vsauce without going off topic 10 seconds into the video, i love it.

[aureusknighstar]

"Why are you boiling cold water?"

"Because I thought it boils faster, Chef"

*"...What?"*

[cgaccount]

It's real. Here are 5 explanations. So in conclusion... it isn't a real effect and doesn't happen

[aetherblackbolt]

The original story even says "to ensure he had a spot, he put his ice cream in while hot" ie earlier than everyone else. So his hot ice cream had time to be cooled down by the freezer before everyone else could put their cooled down ice cream in. If that time was long enough to be cooled below room temperature, then it would have frozen faster.

[scofah]

I love love love that your video isn't full of unnecessary sound effects and music. Honestly I'm so sick of the audio hype on the other channels. Thank you for just sharing without all that background noise.

[EEVblog]

OMG don't mention water "memory"! The homeopathy quacks will have a field day.

[gisnerd]

If you feel one day that you have discovered something new and unusual, mind it guys... there is always a Greek homie who found it centuries ago. XD

[purplgrape]

This reminds me of something I've heard about Ice melting in salt water. Normally you'd expect it to melt faster with saline content. But because it dilutes the upper layers of the water, makes it less dense, so there's less mixing going on than there would be otherwise, had it melted in pure water. This thin upper layer of less dense water would gradually become cooler as the ice melts, which in turn makes it harder to melt more ice. It's a weird thermohaline balancing act.

Without this, the artic ice probably would've been dramatically smaller now.

[xenaguy]

I learned that the Mpemba Effect both does, and does not, exist.

[nliehugtil]

Can we see an infrared recording of hot water vs cold water being cooled? Then we don't have to keep measuring the temperature of water at specific points with a thermocouple and making measurement errors like this.