Thanks my friend. And thanks for commenting about the upcoming thermistor video. I wasn't sure if there'd be any interest. I sure found it useful! The video should be out in 2 weeks.
Thank you so much! This actually helped me understand the concept of how colder temperatures in the ocean result in lower salinity, due to less evaporation. I appreciate and respect the time and effort you put into these videos, and hope I can see more in the future!
The word fast corresponds to speed. Speed is progress / time (/ as in divided by). The word boil doesn't represent progress, rather it represents goal. It doesn't make sense to say how fast you get to a point. It will only make sense to say how fast you move to get to a point. It will only make sense to say how fast water heats up. What we should actually use is the word quick instead, since in this case (boil) it's the time that we care about and not "speed".
Myth busting and science combined this week. Many think cold water boils faster than hot water. Here I do experiments to test that and then explain some of science behind heat transfer that may explain why the myth exists.
@@godschild5587 You're probably brainless in two ways. And you don't even see the quotation marks on my comment. It's a reference from a different video idiot.
@@purpleapple4052 they lie to decieve the simple minded people that the erth is created by random accident aka big bang and there is no creator and we are hybrid monkey living on a spinning space ball, but in reality earth is stationary plane not a planet with a firmament aka dome above us, the firmament is a firm ceiling of earth, outer space does not exist, Bible and science verify the stationary plane earth with a firmament above us, we all must repent our sins in order to go heaven, if you enjoy sins and don't repent then you will be in hell fire for eternity torment, this is what the world leader aka shadow government doesn't want you to know because they are working for satan.
I'm with you on that, but I've heard it a number of times over the years. One possible explanation I came up with was the one I gave in the video, the greater temperature difference between cold water and the heating element causes faster heat transfer, and maybe some people misunderstand that to mean it'll boil sooner, which it doesn't because the heat transfer rate decreases as the water gets hotter.
I'am not shure for "why the variation speed slows down" : your heat source is red glowing, it's around 750°C. So the difference between the water and the resistor temperature is piratically constant during heating. The main explanation is the fact that water is approaching it's vaporizing point, so the saturated vapor pressure is increasing. An increasing fraction of the water is converted to vapor the reach this pressure under the liquid water. This required a huge amont of energy that will not be used to increase the temperature of the liquid water. At 100°C the vapor pressure is more than the atmospheric pressure so 100% of the energy is used to vaporise the water (and because the room is open the pressure will never increase so it you boil as long as there is water is the pan). The temperature is blocked to 100°C :) If the pan was airthigh (and a little bit insulated), the speed will be constant (but the specific capacity of water alose moves, life is complicated ^^). Great videos !!
I agree with that you're saying. As the water temperature approached 100C, more of the energy is going into converting the water into steam and so there is less heating. And thanks! I'm glad you're enjoying my videos. I look forward to more of your videos too.
My old roommate who took way too many post secondary classes, one being a physics class or 3, somehow led her to believe that cold water boils faster. She explained to me a few years ago how which I cannot remember. Can’t wait to send this excellent video to her.
I came across the same question when I was looking into boiling side of things. I didn't look into it though. Maybe in another video? I glad you enjoyed the science class. Thanks.
Excellent analogy! It's too bad I can't go back in time and put it in. Just one minor clarification, though it's for others since clearly know it, "... but the cold did actually drive faster while it was still cold." Unfortunately "cold" can be taken to mean "the one that started cold" or "a cold temperature".
Good question. If I'd filled the pot, then it would have taken longer to boil. That would have given more time and space for heat loss out the sides. That heat loss would have added variables to the experiment and I wouldn't have been able to subtract those variables from the graph. I know this only because I did try a soda can with the top removed so that I could use the thermometer. It took 13 minutes to boil, for the same volume of water, i.e. huge heat losses! I experimented a lot. :)
I would expect just the opposite. If the water was taken from the same place then they contain the same thing, so one isn't any dirtier than the other. The only difference is in temperature. But heating water kills any bacteria that may be in the water. That's why water is sometimes boiled in order to sterilize it. So in that sense, if both started out with bacteria, the water that was boiled will be cleaner.
Thanks. And there wouldn't be a need to show the experiment if there wasn't the misconception. Plus the resulting graph allowed me to point out how dissimilar heat transfer rates result from different temperature differences. That, and watching science in action is fun. :)
Glad to hear Grant's sending people this way! What's funny is that the Steam Vacuum video I mention at the end points right back at Grant! Can you tell we like each other's videos? :)
It would have taken a long time to boil and during that time there would have been a lot of heat losses out the top and sides. Those losses would have contributed to the results, making them less meaningful. I figured the amount of water I boiled was a good compromise.
So while "faster" would normally be taken to mean "takes less time", the average heat transfer per second is actually greater for the cold water. If it had been a race between two cars, the hot car would have finished first due to a head start, but the cold did actually drive faster.
Interesting video. It makes me wonder about how this applies to Stirling engine heat transfer. Keeping the engine in the colder range might be a good idea.
I've heard this one but about freezing - people saying that hot water freezes faster than cold water (which is just silly, IMO). I think both of these are from people mis-remembering that if you put hot water in an ice cube tray, the ice will (supposedly) be more clear than if you start with cold water.
But you do take advantage of this in Stirling engines. You keep one side of the cylinder hot and the other cold. The colder the cold side is with respect to the hot air inside the cylinder, the faster that hot air is cooled so that you can repeat the whole cycle quickly again.
Nice experiment but I think it is wrong to assume that water instantly vaporizes when it reaches 100°C. What about latent heat of vaporization? A quick google search says that it takes 100 calories to heat 1 gram of water from 0 to 100 deg, but it takes 540 calories to take that 100 deg water to boil due to the latent heat of vaporization. Wouldn't this process dominate and bring both total times much closer together?
The thing to note is that while hot water will come to a boil faster, it's not good for you to drink the water from your water heater - especially as the heater ages. Over time, all water heaters will collect sediments and other particulates from the water that goes through it. This is especially true for people who have well water, or for people who have hard water where they live. Using water from the cold water heater for cooking and drinking isn't good for you. In some cases, depending on your overall water quality and the age of your cold water heater, it can even give you medical issues like kidney stones. Your best bet is to use water from the cold water tap and deal with the extra minute or so that it takes for the water to reach a boil.
Why didn't you just add more water to the pot so that the thermometer was submerged sufficiently? Also, I use cold water for drinking and cooking because I heard using warm or hot water picks up more undesirables from the pipes, but I don't actually know if this is true.
I didn't add more water because I didn't want heat losses from the rest of the pot to affect things. Regarding using cold water instead of warm or hot, I wonder about the same thing, especially first thing in the morning.
Ah, but the rate of energy transfer isn't the same. It depends on the temperature difference, which changes as the water heats up. While the water is still cold, the energy transfer is faster. I think that's what makes people think cold water boils faster. And thanks. I'm glad you like my experiment.
I've been asked to do a TEA laser and just explaining lasers has been on the todo list for a while. I'll see about bumping it up. It's hard when you have many items all at the top of the list! :)
Air pressure decreases the higher you go up. And the lower the pressure, the lower the boiling temperature/time. So yes, water in Denver would boil faster than water at sea level.
Thanks for the tip. A lot of people have suggested doing the freezing experiment but I haven't looked into the feasibility of doing a proper one yet so I'm not certain if I'll be able to. We'll see. BTW I'm Steve. Grant's at King of Random. :)
My hot plate will automatically turn off after a certain time. It's usually before I can boil the water. Once off it will remain off until the burner falls low enough temp. Sadly it turns off before I can bring my water to boil. Offset this I have been putting my water in the microwave for a few minutes before I poor it into the pot to boil. My concern was since hot water heats at a slower rate than cool water then my efforts made no difference. I'm glad to learn that it does. The best analogy I can think of is if I raced Usain bolt in the 100 meter dash. Only I'm allowed an 80 meter head start. He's cold I'm hot. Bolt may be faster but I will reach the finish sooner bc I'm closer to begin with. Glad to know my efforts are not in vein
Another answer is also because the water does heat up uniformly. The water at the bottom of the vessel reaches boiling temperature sooner than water near the top
It would have taken longer to boil and during that time there would have been more losses out the sides and top. Those losses would have affected the test results too much.
Thanks Grant. Good explanation. It reminds me of a supposed science nomer passed around years ago having people believe that room temperature water does not freeze faster then boiling water. What they did is put samples of both in a freezer and time them.
Great video but here's what I think you might have missed. Most people who think cold water boils faster are actually the one who have subconsciously heard/know about the Mpemba effect: where hot water sometimes freezes faster than cold water. So they assume the vice versa is also true!
So is this curve a reflection of heat loss , rather than heat gain . As the temperature increases it sheds into the surroundings , and as it temperature notably outstrips the exterior there is dispassionately more convection & radiation leading to a curve . If this system was lagged ie an electrical element in the water & a well lagged / insulated cylinder & little air to convect the heat away , would it be closer to a straight line ?
The curve is a reflection of heat transfer, a heat loss from the water and a heat gain to the surrounding room. Strictly speaking the curve isn't due to convection. It's just a property of how heat is transferred by conduction from one medium to another medium. As the temperature difference increases the heat transfer happens faster. I have a webpage all about it on my website, including a handy calculator so you can play with different temperatures but the formula's there too: rimstar.org/renewnrg/heat_transfer_loss_calculations.htm
I heard that hot water freezes faster. Is that the same thing or will hot water turn into ice cubes sooner than cold water. My parents held opposite views and in my first science class at college the instructor said hot water freezes faster but did not do the in depth experiment that you presented for boiling water. Thank you for the lovely science class.
The reason many people believe it's better to use cold water is because many water heaters are too cold to kill much of the bacteria in tap water, in fact, if your water heater is too cold (below 120°F) bacteria can thrive. 120°F is about normal for a water heater, but to kill 99% of the bacteria you need your water heater at at least 140°F, just be sure to have a temperature regulator valve before the water reaches the taps, as it would be easy to accidentally get burned.
Cold water does not boil faster than hot water. The rate of heating of a liquid depends on the magnitude of the temperature difference between the liquid and its surroundings (the flame on the stove, for instance). As a result, cold water will be absorbing heat faster while it is still cold; once it gets up to the temperature of hot water, the heating rate slows down and from there it takes just as long to bring it to a boil as the water that was hot to begin with. Because it takes cold water some time to reach the temperature of hot water, cold water clearly takes longer to boil than hot water does. There may be some psychological effect at play; cold water starts boiling sooner than one might expect because of the aforementioned greater heat absorption rate when water is colder.
How does it work in relation with more water For example would 80litars of warm water(vs 80L of cold water) boil faster or slower Than 1 litar of warm water vs 1l of cold water
How about water that had previously been frozen and then returned to room temperature. would that water boil faster than water that had not been frozen?
No, it wouldn't boil faster. From any given temperature, the remaining time to boil is the same. You can see this in charts in the video. Once the temperatures overlap on the chart, they keep overlapping.
Isn't the interesting question how long does it take to boil cold or hot water starting from a room temperature stove (basic, not induction). I don't want to test it since hypotheticals are more exciting then answers, but I'd say the difference is negligeable.
The confusion is not in the situation but in the semantics. Cold water does not boil at all. Assuming that the term "boils" in "Does cold or hot water boils faster?" means reach its boiling point faster, we are left with the ambiguity of what exactly "faster" means. "Fast" is often used to describe any event that happens in a short period of time regardless of any rate function. So even a slower racer who's close enough to the finish line might finish faster than a racer whose speed's greater.
@@EnjoyTheSilenc3 Under our definition of the Mpemba effect, akin to the definition in the 'original' paper by Mpemba & Osborne8 (in which they documented “the time for water to start freezing”) we are forced to conclude that the 'Mpemba effect' is not a genuine physical effect and is a scientific fallacy.Nov 24, 2016. Nature publication.
Sorry to be that guy, but shouldnt both of the times for the hot and cold start from 0? Why does the hot start at 53 seconds? Im pretty sure you goofed the chart up... like if that were to be graded id have to give you like 50 percent
In answer to your question, the chart shows two test runs done at different times as shown in the video and then drawn on the same chart. The length of the runs took different amounts of time because the hot water started at a hotter temperature -- there is no data before that temperature. I overlapped them by finding the same temperature in the cold data (well, 55 for the cold and 56 for the hot). That way they had the same starting point.
@@RimstarOrg yes that is all fine and well. But the x axis represents the amout of time you heated the water, in order for it to boil. I dont mind really, it just erks me that you didnt plot the time data correctly, ie, starting from right when you began heating, the time that it has been heated should be zero. Correct? Other than that thank you for the video it answered my question well.
You have to use more water than that. With that amount of water it doesn't mattter if you put hot or cold in there is hardly any volume so of course its going to absorb the heat from the pot right away. Add 3 cups and retest 8 years later.
Oh and also, poorly maintained water heaters build up a lot of sediment and other junk at the base of the tank, which can contaminate the water. It is recommended to fully drain your tank twice a year.
#2 What they did not take into consideration is that because both were put in the same space simultaneously, the freezer must cool the space as a whole and the hot one warms the space . so both will freeze roughly at the same time. But if the experiment was conducted in two separate freezers the outcome would be be different.
I don't think that's the reason people think that. If you throw cold water at a frying pan you hear a noticeable noise, if you throw hot water at it you hear nothing. Or am I wrong?
There is some good buys on lesser but adequate dig thermometers on E bay though you need to weed through the mess, just search for " K type thermometer" and narrow by buy now. I bought a duel probe w high and low memory for less then $15 a few months back Unfortunately I think those ones sold out but there are some other decent ones out there.
People referencing the Gordon Ramsay video, and I'm over here remembering the small town I came from where many people genuinely, unironically, whole-heartedly believed cold water boiled faster.
Gordon Ramsay: w h o t
@@TheGrayton2000 i saw her first
Sanctuary Guardian intensifies
@@elkeh1073 .
@@VanWolf lol
@@gillsnotlora oh shee wrong video lol my bad
Thanks for giving the answer at the beginning of your video.
😂 😂 😂 the sarcasm here hurts
@@dopeknowsnathaniel It isn't sarcasm, the answer is in the beginning
@@CaseyFrazAnimations yes, i know, but Justin said it in a sarcastic manner. My reply was to his post not the video. 😕😕
@Ascended Master can't you ? if you can't then you clearly aren't on my level of expertise 😕
@@dopeknowsnathaniel there is no sarcasm
That one chef from Hell’s Kitchen didn’t watch this video
So... You too, huh? XD
@@VarunGupta3009 Me too.
_" W h a t ? "_
- Gordon Ramsay
@@VarunGupta3009 yep me too
Me too
Lmao here from that video as well
"I though cold water was supposed to boil faster that hot water"
*"w h o t ?"*
And you probably believe yes believe that earth is a spinning space ball.
@@godschild5587 w h o t
@@godschild5587 w h o t
@@LoneCat2137 w h o t
@@godschild5587 what?
Myth Busted! Nice job Steve :)
The King of Random rip grant.
@@KhoiTTA why are you here?
Rip my nigga
Rest in peace, friend.
@@ptr2307 lmao
That was a great demonstration
2:09
_With the stove element nice and hot_
_I poured the water into the pot._
Dr.Suess
@@alucardbunche4197 too late are we?
Hahaha I came from the video with Gordon Ramsay.
Me too 😂😂
Thanks my friend. And thanks for commenting about the upcoming thermistor video. I wasn't sure if there'd be any interest. I sure found it useful! The video should be out in 2 weeks.
Thank you so much! This actually helped me understand the concept of how colder temperatures in the ocean result in lower salinity, due to less evaporation. I appreciate and respect the time and effort you put into these videos, and hope I can see more in the future!
The word fast corresponds to speed. Speed is progress / time (/ as in divided by).
The word boil doesn't represent progress, rather it represents goal.
It doesn't make sense to say how fast you get to a point. It will only make sense to say how fast you move to get to a point.
It will only make sense to say how fast water heats up.
What we should actually use is the word quick instead, since in this case (boil) it's the time that we care about and not "speed".
Most people won't understand what you've said. But, I think the fight for proper English is important and that you've make a good point.
I love how we actual need a video like this to prove that colder water takes more time to reach 100 degrees than hot water
Well, hot water does freeze faster than cold water. Soo.....
@@alexz4427 well he is actually right ruclips.net/video/oS8jHfbcme8/видео.html
@@Hugolaste a
@@Hugolaste well he actually isn’t, and neither are you ruclips.net/video/SkH2iX0rx8U/видео.html
@@alexanderenfloristijburg8211 actually you're both wrong ruclips.net/video/dQw4w9WgXcQ/видео.html
Anyone else here because of Gordon Ramsey?
Im here from Gordon's confusion on that one video
same lmao
You sound like the narrator from “Grandma Got Run Over By A Reindeer” and it’s mad comforting ngl. No homo
Myth busting and science combined this week. Many think cold water boils faster than hot water. Here I do experiments to test that and then explain some of science behind heat transfer that may explain why the myth exists.
"I thought cold water was supposed to boil faster than hot water!"
Whaaaat?
You probably believe the earth is a spinning space ball.
@@godschild5587 You're probably brainless in two ways. And you don't even see the quotation marks on my comment. It's a reference from a different video idiot.
@@godschild5587 why would nasa and/or the other space agencies all over the world lie that the Earth is round?
@@purpleapple4052 they lie to decieve the simple minded people that the erth is created by random accident aka big bang and there is no creator and we are hybrid monkey living on a spinning space ball, but in reality earth is stationary plane not a planet with a firmament aka dome above us, the firmament is a firm ceiling of earth, outer space does not exist, Bible and science verify the stationary plane earth with a firmament above us, we all must repent our sins in order to go heaven, if you enjoy sins and don't repent then you will be in hell fire for eternity torment, this is what the world leader aka shadow government doesn't want you to know because they are working for satan.
I'm with you on that, but I've heard it a number of times over the years. One possible explanation I came up with was the one I gave in the video, the greater temperature difference between cold water and the heating element causes faster heat transfer, and maybe some people misunderstand that to mean it'll boil sooner, which it doesn't because the heat transfer rate decreases as the water gets hotter.
I'am not shure for "why the variation speed slows down" : your heat source is red glowing, it's around 750°C. So the difference between the water and the resistor temperature is piratically constant during heating. The main explanation is the fact that water is approaching it's vaporizing point, so the saturated vapor pressure is increasing. An increasing fraction of the water is converted to vapor the reach this pressure under the liquid water. This required a huge amont of energy that will not be used to increase the temperature of the liquid water. At 100°C the vapor pressure is more than the atmospheric pressure so 100% of the energy is used to vaporise the water (and because the room is open the pressure will never increase so it you boil as long as there is water is the pan). The temperature is blocked to 100°C :)
If the pan was airthigh (and a little bit insulated), the speed will be constant (but the specific capacity of water alose moves, life is complicated ^^).
Great videos !!
I agree with that you're saying. As the water temperature approached 100C, more of the energy is going into converting the water into steam and so there is less heating.
And thanks! I'm glad you're enjoying my videos. I look forward to more of your videos too.
My old roommate who took way too many post secondary classes, one being a physics class or 3, somehow led her to believe that cold water boils faster.
She explained to me a few years ago how which I cannot remember. Can’t wait to send this excellent video to her.
I came across the same question when I was looking into boiling side of things. I didn't look into it though. Maybe in another video? I glad you enjoyed the science class. Thanks.
The scientific method rocks! Glad you like it.
Excellent analogy! It's too bad I can't go back in time and put it in. Just one minor clarification, though it's for others since clearly know it, "... but the cold did actually drive faster while it was still cold." Unfortunately "cold" can be taken to mean "the one that started cold" or "a cold temperature".
Good question. If I'd filled the pot, then it would have taken longer to boil. That would have given more time and space for heat loss out the sides. That heat loss would have added variables to the experiment and I wouldn't have been able to subtract those variables from the graph. I know this only because I did try a soda can with the top removed so that I could use the thermometer. It took 13 minutes to boil, for the same volume of water, i.e. huge heat losses! I experimented a lot. :)
I would expect just the opposite. If the water was taken from the same place then they contain the same thing, so one isn't any dirtier than the other. The only difference is in temperature. But heating water kills any bacteria that may be in the water. That's why water is sometimes boiled in order to sterilize it. So in that sense, if both started out with bacteria, the water that was boiled will be cleaner.
Thanks. Looks like they have a nice wide temperature range too.
Its a blast from the past seeing someone reply to another comment without being able to do threads.
Thanks. And there wouldn't be a need to show the experiment if there wasn't the misconception. Plus the resulting graph allowed me to point out how dissimilar heat transfer rates result from different temperature differences. That, and watching science in action is fun. :)
Glad to hear Grant's sending people this way! What's funny is that the Steam Vacuum video I mention at the end points right back at Grant! Can you tell we like each other's videos? :)
Bruh
It would have taken a long time to boil and during that time there would have been a lot of heat losses out the top and sides. Those losses would have contributed to the results, making them less meaningful. I figured the amount of water I boiled was a good compromise.
I'll have to look into the freezing question. I didn't know about it until I was doing research for this video. Thanks for asking.
Thanks. I think I've heard of it before too, though I made the video because someone recently asked about it in a comment.
So while "faster" would normally be taken to mean "takes less time", the average heat transfer per second is actually greater for the cold water. If it had been a race between two cars, the hot car would have finished first due to a head start, but the cold did actually drive faster.
Ofcourse! Cold water molecules are oscillating on low frequency that means it will consume more energy to reach the boiling point temperature
Interesting video. It makes me wonder about how this applies to Stirling engine heat transfer. Keeping the engine in the colder range might be a good idea.
I have never heard of this myth that cold water boils faster than hot water. But I like the way you went about testing it. The data doesn't lie!
Thanks Rick. Good job on that tall fire tornado of yours.
RimstarOrg Thanks! As fun as that was I still kind of want to make a bigger one...
I've heard this one but about freezing - people saying that hot water freezes faster than cold water (which is just silly, IMO).
I think both of these are from people mis-remembering that if you put hot water in an ice cube tray, the ice will (supposedly) be more clear than if you start with cold water.
I suspect that if we were to test the freezing myth the graphs would look similar to what was show in in this video, only in reverse.
Dave Durant
Oh! That's a new one for me. I don't make ice cubes often but I'll have to try that and see.
But you do take advantage of this in Stirling engines. You keep one side of the cylinder hot and the other cold. The colder the cold side is with respect to the hot air inside the cylinder, the faster that hot air is cooled so that you can repeat the whole cycle quickly again.
Nice experiment but I think it is wrong to assume that water instantly vaporizes when it reaches 100°C. What about latent heat of vaporization? A quick google search says that it takes 100 calories to heat 1 gram of water from 0 to 100 deg, but it takes 540 calories to take that 100 deg water to boil due to the latent heat of vaporization. Wouldn't this process dominate and bring both total times much closer together?
Thanks. And yup, it wants to get to hotter but it just throws it all away!
The thing to note is that while hot water will come to a boil faster, it's not good for you to drink the water from your water heater - especially as the heater ages. Over time, all water heaters will collect sediments and other particulates from the water that goes through it. This is especially true for people who have well water, or for people who have hard water where they live. Using water from the cold water heater for cooking and drinking isn't good for you. In some cases, depending on your overall water quality and the age of your cold water heater, it can even give you medical issues like kidney stones. Your best bet is to use water from the cold water tap and deal with the extra minute or so that it takes for the water to reach a boil.
Thats why i think its weird for Gordon a chef to complain about cold water in his resturant.
Why didn't you just add more water to the pot so that the thermometer was submerged sufficiently?
Also, I use cold water for drinking and cooking because I heard using warm or hot water picks up more undesirables from the pipes, but I don't actually know if this is true.
I didn't add more water because I didn't want heat losses from the rest of the pot to affect things.
Regarding using cold water instead of warm or hot, I wonder about the same thing, especially first thing in the morning.
that’s the explanation of the woman from gordon ramsay. now i get it
but how much time did you spend waiting for the faucet water to get hot before you could use it that is extra time not needed when using cold water
Oh, really? I'd only heard of the freezing one recently, so that logic hadn't even occurred to me. Thanks for clarifying.
Ha! I didn't even think of it as myth busting! Nice twist, Grant. I should have thought of that. :)
when you compare the time to temperature (2mins = 55 degrees for example) they actually boil at the same speed
Gordon Ramsay vs flat girl bring me here
Ah, but the rate of energy transfer isn't the same. It depends on the temperature difference, which changes as the water heats up. While the water is still cold, the energy transfer is faster. I think that's what makes people think cold water boils faster. And thanks. I'm glad you like my experiment.
I've been asked to do a TEA laser and just explaining lasers has been on the todo list for a while. I'll see about bumping it up. It's hard when you have many items all at the top of the list! :)
Does elevation affect the boiling time? I live in Denver and have never had water boil in under two minutes
Air pressure decreases the higher you go up. And the lower the pressure, the lower the boiling temperature/time. So yes, water in Denver would boil faster than water at sea level.
This myth never made any sense to me because at some point while the cold water heats up it has to reach the temperature the hot water starts at..
Thanks for the tip. A lot of people have suggested doing the freezing experiment but I haven't looked into the feasibility of doing a proper one yet so I'm not certain if I'll be able to. We'll see. BTW I'm Steve. Grant's at King of Random. :)
My hot plate will automatically turn off after a certain time. It's usually before I can boil the water. Once off it will remain off until the burner falls low enough temp. Sadly it turns off before I can bring my water to boil.
Offset this I have been putting my water in the microwave for a few minutes before I poor it into the pot to boil.
My concern was since hot water heats at a slower rate than cool water then my efforts made no difference. I'm glad to learn that it does.
The best analogy I can think of is if I raced Usain bolt in the 100 meter dash. Only I'm allowed an 80 meter head start. He's cold I'm hot. Bolt may be faster but I will reach the finish sooner bc I'm closer to begin with. Glad to know my efforts are not in vein
Another answer is also because the water does heat up uniformly. The water at the bottom of the vessel reaches boiling temperature sooner than water near the top
It would have taken longer to boil and during that time there would have been more losses out the sides and top. Those losses would have affected the test results too much.
Thanks Grant. Good explanation. It reminds me of a supposed science nomer passed around years ago having people believe that room temperature water does not freeze faster then boiling water. What they did is put samples of both in a freezer and time them.
Thanks. And welcome!
0:04 probably because this is taught in common core.
Great video but here's what I think you might have missed. Most people who think cold water boils faster are actually the one who have subconsciously heard/know about the Mpemba effect: where hot water sometimes freezes faster than cold water. So they assume the vice versa is also true!
You forgot something. The amount of time it takes for the tap water to get hot.
So is this curve a reflection of heat loss , rather than heat gain . As the temperature increases it sheds into the surroundings , and as it temperature notably outstrips the exterior there is dispassionately more convection & radiation leading to a curve . If this system was lagged ie an electrical element in the water & a well lagged / insulated cylinder & little air to convect the heat away , would it be closer to a straight line ?
The curve is a reflection of heat transfer, a heat loss from the water and a heat gain to the surrounding room. Strictly speaking the curve isn't due to convection. It's just a property of how heat is transferred by conduction from one medium to another medium. As the temperature difference increases the heat transfer happens faster. I have a webpage all about it on my website, including a handy calculator so you can play with different temperatures but the formula's there too: rimstar.org/renewnrg/heat_transfer_loss_calculations.htm
I don't know why it's not obvious. But to some it isn't, hence the need to show the experiment.
i came for the “why do people believe this?” part, so thank you for including it
Now of course you have to factor in the time it takes for your tap to get to the hot water.
how about filling the pan with water and using the same heat under the pan. That hot iron you have under the pans gets hotter and then stops
I heard that hot water freezes faster. Is that the same thing or will hot water turn into ice cubes sooner than cold water. My parents held opposite views and in my first science class at college the instructor said hot water freezes faster but did not do the in depth experiment that you presented for boiling water. Thank you for the lovely science class.
Just because hot water freezes faster than cold water, doesnt mean the opposite is true
Thanks for going thru all that for the information. Much appreciated! Now I can explain why next time someone says this.
The reason many people believe it's better to use cold water is because many water heaters are too cold to kill much of the bacteria in tap water, in fact, if your water heater is too cold (below 120°F) bacteria can thrive. 120°F is about normal for a water heater, but to kill 99% of the bacteria you need your water heater at at least 140°F, just be sure to have a temperature regulator valve before the water reaches the taps, as it would be easy to accidentally get burned.
Why did i get this recommendation 7 years later 🤔
Cool vid. Where it gets really interesting is the latent heat of state change during that last degree rise, before steam :)
Because of kitchen from hell by gordon ramsey meme, i come to this video, thank you for break the myth and thank you for the answer👍👍👍
On the contrary, hot water freezes faster than cold water. It's called Mpemba effect
wouldn't the curve be explained by partial evaporative cooling?
Have you tried to test the Mpemba effect too?
No, I haven't.
Cold water does not boil faster than hot water. The rate of heating of a liquid depends on the magnitude of the temperature difference between the liquid and its surroundings (the flame on the stove, for instance). As a result, cold water will be absorbing heat faster while it is still cold; once it gets up to the temperature of hot water, the heating rate slows down and from there it takes just as long to bring it to a boil as the water that was hot to begin with. Because it takes cold water some time to reach the temperature of hot water, cold water clearly takes longer to boil than hot water does. There may be some psychological effect at play; cold water starts boiling sooner than one might expect because of the aforementioned greater heat absorption rate when water is colder.
How does it work in relation with more water
For example would 80litars of warm water(vs 80L of cold water) boil faster or slower
Than 1 litar of warm water vs 1l of cold water
How about water that had previously been frozen and then returned to room temperature. would that water boil faster than water that had not been frozen?
No, it wouldn't boil faster. From any given temperature, the remaining time to boil is the same. You can see this in charts in the video. Once the temperatures overlap on the chart, they keep overlapping.
Isn't the interesting question how long does it take to boil cold or hot water starting from a room temperature stove (basic, not induction). I don't want to test it since hypotheticals are more exciting then answers, but I'd say the difference is negligeable.
The confusion is not in the situation but in the semantics.
Cold water does not boil at all.
Assuming that the term "boils" in "Does cold or hot water boils faster?" means reach its boiling point faster, we are left with the ambiguity of what exactly "faster" means. "Fast" is often used to describe any event that happens in a short period of time regardless of any rate function. So even a slower racer who's close enough to the finish line might finish faster than a racer whose speed's greater.
Obviously warm water boils faster since it starts out warmer?
Nocure92 Yup, but for some reasons there's this urban myth that cold water boils sooner.
So explain why hot water freezes faster than cold water by your logic?
Is that a question or statement.
Casey Reynolds a command
@@EnjoyTheSilenc3
Under our definition of the Mpemba effect, akin to the definition in the 'original' paper by Mpemba & Osborne8 (in which they documented “the time for water to start freezing”) we are forced to conclude that the 'Mpemba effect' is not a genuine physical effect and is a scientific fallacy.Nov 24, 2016. Nature publication.
How come you didn't just use more water with the kitchen thermometer?
I was concerned that if I put too much water then there would be more surface area for heat loss to the metal pot.
Sorry to be that guy, but shouldnt both of the times for the hot and cold start from 0? Why does the hot start at 53 seconds? Im pretty sure you goofed the chart up... like if that were to be graded id have to give you like 50 percent
In answer to your question, the chart shows two test runs done at different times as shown in the video and then drawn on the same chart. The length of the runs took different amounts of time because the hot water started at a hotter temperature -- there is no data before that temperature. I overlapped them by finding the same temperature in the cold data (well, 55 for the cold and 56 for the hot). That way they had the same starting point.
@@RimstarOrg yes that is all fine and well. But the x axis represents the amout of time you heated the water, in order for it to boil. I dont mind really, it just erks me that you didnt plot the time data correctly, ie, starting from right when you began heating, the time that it has been heated should be zero. Correct? Other than that thank you for the video it answered my question well.
We all know why we’re here.
I thought cold water was to supposed to boil faster then hot water
You have to use more water than that. With that amount of water it doesn't mattter if you put hot or cold in there is hardly any volume so of course its going to absorb the heat from the pot right away. Add 3 cups and retest 8 years later.
What?
Awesome man . Looking forward to the video about the termistor stuff.
Oh and also, poorly maintained water heaters build up a lot of sediment and other junk at the base of the tank, which can contaminate the water. It is recommended to fully drain your tank twice a year.
Looks like wendy liu from hell's kitchen didn't get the message
#2 What they did not take into consideration is that because both were put in the same space simultaneously, the freezer must cool the space as a whole and the hot one warms the space . so both will freeze roughly at the same time. But if the experiment was conducted in two separate freezers the outcome would be be different.
Assuming sea level pressure, cold water does not boil at all. You have to heat it to get it to boil.
Why didnt you just fill up the saucepan so you could use the regular thermometer
I was concerned that there would be more heat loss through the sides of the pot, messing with my measurements.
I don't think that's the reason people think that. If you throw cold water at a frying pan you hear a noticeable noise, if you throw hot water at it you hear nothing. Or am I wrong?
You could just say that you wanted to use a sensor. Because you could also put more water...
There is some good buys on lesser but adequate dig thermometers on E bay though you need to weed through the mess, just search for " K type thermometer" and narrow by buy now. I bought a duel probe w high and low memory for less then $15 a few months back Unfortunately I think those ones sold out but there are some other decent ones out there.
The girl from Kitchen Nightmares bought me here
Looks like Wendy didn't watch this video beforehand.
the misconception comes from the fact that hot water freezes faster then cold
it doesn't.
It actually does. Look up the mpenda effect.
It really doesn’t. There’s nothing in Thermodynamics that backs this myth.
yakapoe it does
@@yakapoe it does, stop being dumb and just look it up.
4 seconds into the video: the answer is no
Me: understandable have a good day
People referencing the Gordon Ramsay video, and I'm over here remembering the small town I came from where many people genuinely, unironically, whole-heartedly believed cold water boiled faster.