Hi, i would just like to tell you that you made a mistake when you labeled boiling and evaporation at the same place. its quite a common error, but boiling and evaporation are actually two different things. Evaporation takes place at a very large range of temperature compared to boiling that only takes place when the temperature reaches the boiling point. For example if it were to rain at about 6pm, in countries like where i am (Kenya) where the temperature is not too low (around 20C at night), then in the morning we would find the water to have vaporized, how if it wasn't 100c? this happens because the water molecules at the surface tend to jump out of the liquid surface due to the kinetic energy. Here we can say: Evaporation only takes place at the surface of the liquid at a large temperature range where as boiling takes place at any area of the liquid (reason for bubbles) and at only a certain temperature (boiling point) depending on the liquid. Therefore during evaporation the temperature of the liquid can change but not in boiling.
Hi 1 year ago I was doing my AS and ur videos helped me get an A and a year later, here I am studying similar things are referring to the same amazing videos of yours. Many thanks Doc !!
Heat is thermal energy. I am adding heat but not changing the temperature. Distinguishing heat from temperature is sometimes a tricky process, but it's SO important to understand.
Just saw this now. Evaporation and boiling are two separate things. We're studying these differences in our curriculum, I suggest you annotate a correction, cuz we don't want others viewing this to get confused. Great video tho! :)
+Doc Schuster Oops. sorry for so many replies. there was a glitch on my iPad, it kept saying error. but seriously, I love the way you explain, and I can see that ur passionate. also you respond. Thank you so much!
Disclaimer: It's 1/14/20 and I haven't reviewed all 152 existing comments. The bottom or 'x' axis should be re-labeled 'Time.' That is, the authors stated the heat input was a constant value. So you're simply graphing the temperature of the water over time. You're welcome. Significantly, this demo nicely illustrates why the "Blue Ocean Event"-- when most Arctic ice has melted-- will be game over for most life on earth. Humans included. You're not welcome.
actually, farmerguy, boiling has a specific temperature at where the state change happens, whereas evaporation can happen at a large range of temperatures
Melting called Heat of Fusion, the amount of head absorbed by the system to go from solid to liquid. The video indicated the fusion goes from liquid to solid and that's incorrect.
actually latent heat of fusion is the amount of energy for a solid to undergo a phase change hence it is basically the energy needed for a solid to completely melt so general his statement was correct
This was great! I just wish some of the implications of condensing a lot of water vapor -- with the associated return of the **2.26 x10^6 J/kg of heat** -- had been woven into it. For example, the creation of an average-size cumulus cloud (made of liquid droplets from condensing of vapor onto nucleation aerosols) = the release of how much heat? A: A well-known meteorology textbook has this at about 1 Hiroshima-sized nuclear detonation. For just one cloud. At any rate, a _lot_of heat. I wonder what would happen if we gave our atmosphere more water vapor, say, by heating it up somehow? Oh wait, we don't have to wonder, it turns out we have been doing this very experiment for sometime now. More water vapor (in absolute, not relative terms) means more latent heat available to storms (oh, and more moisture too).
You have written "fusion" and "solidification" in the same direction. But actually they both are opposite of each other . Fusion is change of solid into liquid however solidification is the change of liquid into solid.
fusion and melting is the same. and also evaporation is not the same is boiling. boiling occurs in the temperature where the vapor pressure is equal to external pressure (stove), and once the external pressure overcomes the vapor pressure the molecules of water will evaporate.
Although we see massive ice melt in the arctic and antarctic as icebergs the size of Delaware are breaking off the continental ice sheet, the latent heat of fusion is the reason that we don't see dramatic changes in global temperature. The ice can only absorb so much heat energy. As it melts, the temperature buffering capacity of the global ice sheets decreases, leading to exponential rise in the change in global temperature. Yes, global mean temperature is rising, faster and faster. Thermodynamics never lie.
Labeling the RHS as steam is wrong. Steam is still visible water. Should have been labelled as water vapour, which cannot be seen, but which surrounds us in various quantities in every day life. Other than that, I like it.
Liquid gains heat in order to change to gas, which means that Q is positive (in Q=mL) What is the sign of Q when gas changes back to liquid? Is it negative since heat is lost?
In my text book it given 3.36 X 100000000. When I Google it says 3.34 X 100000000. In ur video it says 3.35 X 100000000. Which 1 is the correct latent heat measure for ice of 1kg.
Darsh Mehta Well, you could perform an experiment, but I'm sure your error would be at least one percent. So it doesn't actually matter. The values you've given are all less than 1% from one another.
I have a ski jacket that claims to harness transition and the latent heat capacity of some undisclosed molecule to regulate the heat of the wearer to around comfortable temperatures. Experientially it's a great ski jacket and I never get too hot or cold but I'd be interested to understand what molecule would be at the transition between liquid and solid and capable of being contained within some other layer such that the wearer didn't feel any change in the jacket. The material is documeted here: www.schoeller-textiles.com/en/technologies/schoeller-pcm.html Is this a lot of nonsense or is it using the principles described in your video?
what happens when i starts from the zero degree?.........does the graph also starts horizontally for a while like this...........and thanks in advance.
Mohamed Madbouly If you start at zero celsius, you have either hot ice, cold water, or some ice water. The fraction that is ice will determine how long it spends at 0 C before beginning to warm (all ice needs to melt first).
Doc Schuster.i am a university student studying engineering and you explained this part better than my doctor did...really you are a great man.....many thanks for these videos...and merry Christmas
Doc Schuster I think evaporation happens all the time, while boiling only happens when the fluid is at its boiling point. But i guess in this case you can use evaporation as well... anyway thanks for the informative vid.
will rubio What is actually annoying is that you (and I) were raised in a backward culture that refuses to use a system that is objectively superior and in use in literally every other country in the world. I'm so sorry.
