@Lachieh923 True, but then you're not really "boiling" the liquid you're trying to freeze. (I could have also just put the water in the freezer, but where's the fun in that?) :)
This video is good preparation for undergraduate thermodynamics courses where the first question asked must be, "What is my system?" This usually involves drawing a cartoon of the process and putting a dashed line around the particular thing that you're interested in. Different "sub-plots" emerge if an open system is defined (for example, all the flask contents or the liquid acetone in the flask) or if a closed system is defined (for example, all the acetone regardless of its location or state).
Don't make it complicated. Evaporation is a cooling process. If something evaporates quick enough it freezes. Since it overcomes the amount of heat being absorbed
@tangnatalaga True, and point taken. However, rarely will you see something evaporate fast enough to freeze itself... (perhaps since solids typically sublime much slower than liquids evaporate...)
Boiling point is defined as the point in which the vapor pressure of the liquid is equal to the surrounding air pressure. Vapor pressure is higher at higher temperatures, therefore at a relatively low temperature (~25 C), water and acetone will have low vapor pressures, with acetone's higher than water's(difference in intermolecular forces). Reducing pressure(vacuum) causes acetone to boil first; boiling(breaking bonds) requires energy input, which is taken from the water, causing it to freeze.
Why did you need acetone? With a good enough vacuum pump you should have been able to make plain water boil and carry away enough heat to freeze the remainder. Was your pump simply not able to drop the pressure quickly enough? In that case you could exhaust a large tank first and then open a valve between it and the bell jar to drop the pressure to near vacuum almost instantly.
@ApolloWasReal I saw this experiment successfully completed using plain water in a college chemistry class 25+ years ago. I don't remember all of the details, but I believe we had some type of material (possibly desiccant) in the bell jar also. As I recall this was to further reduce the vapor pressure. The basis of the experiment was to show that boiling is a cooling process (the liquid gives up heat) and that the vapor pressure around the liquid is what controls the boiling point temp.
@vaheedh Not really. Being a vacuum, outer space has no temperature. But if you were to open up a bottle of water in space, it would instantly start boiling and that would carry away so much heat so quickly that it would freeze the remainder. The Apollo astronauts used exactly this method to stay cool on the moon, though it was practical for them only because they were there only a short time. Water is otherwise far too precious on the moon to let it just boil away!
@sciencetheater so let me see if i got this right, so you're boiling it by , instead of increasing the pressure of air in the liquid( by raising it's temperature) you decrease the pressure outside the liquid, which causes the liquid to boild, which under the lack of air pressure in the acetone the acetone absorbs heat from the water
if i understand that correctly i'm quite amazed, and i thank you for teaching me this
@kionay Sounds like you got it. Acetone boils due to low air pressure, cooling it off (perhaps think of evaporation rather than boiling), which reduces the temperature of the liquid, so the water in the liquid turns to ice.
@anmluvr91 I don't think it actually turned black, it just looked that way to the camera because the ice and liquid droplets covered the inside and scattered the light passing through it.
@IanGamil I bleach my hair (leaving the bleach in longer than I should), then rinse and immediately put in my haircolor. I use "Directions" which I get from over in the UK. I leave that in a long time, too, then rinse. The color lasts about a week, and fades almost away in two weeks. Seems to do a bit better if I use conditioner right after coloring...
@EcoDimension They're little rocks made out of marble, not marbles. They're there to try to prevent explosive boiling (when the liquid just blows up all at once... the chips provide a spot for the bubbles to form when the liquid degasses and boils.) The demo should work with pure water but I suspect using acetone makes it easier/more reliable.
I wouldn't call it supersaturating.. I mix acetone and water, reduce the air pressure to let the acetone boil off. That removes heat from the system and makes the water freeze.
by reducing the pressure, you reduce the amount of energy the liquid requires to break free from itself because there is less pressure holding it together.
acetone boils at a lower temperature than water at normal pressure, and the same goes for when the vacuum is applied. when the acetone boils, its higher energy molecules are flying away, leaving the colder ones behind. as this continues, more and more high energy molecules leave, hence the cooling. eventually it freezes
Hey! I was trying to recreate your experiment in the school last week but didn't quite succeed.
We reached the temperature of -3 or -4 degrees Celsius, but it didn't freeze. We were measuring the volumes and it seemed like some of the acetone remained in the mixture, therefore lowering the melting point. We were using the water vacuum pump (based on Venturi effect).
Could it be, that this pump was not creating enough vacuum? What pump are you using.
acetone to water ratio is important... try reducing the amount of acetone. My vacuum wasn't that great so I had to be careful about it as well. Make sure there is as little thermal conduction into the beaker from the base as possible. (try putting it on a piece of cork or something...
Not sure of my ratio, try a search online. It was ballpark 50/50 but maybe a tad less acetone. I tried it twice before filming...
If you could keep the liquid from touching the sides of the container, then it would stay cold a long time. (Convection and conduction wouldn't add any heat...)
You'd also need to keep it in the dark, to keep radiation (another source of heat energy) from warming it up...
Where can I get a vacuum pump and a bell jar like that? Or better yet, where can I get a kit to where I can make water freeze in a vacuum...thanks...I imagine it's expensive
There's an equation that expresses the energy (heat) given off when a solid is formed...
You could use the heat of formation of ice and the heat of vaporization of alcohol to talk about the cooling of the liquids. That is simply: Q = mC where m is the mass and "C" would be the heat of vaporization or cooling of the respective liquid.
You need a vacuum pump (not a high end one, but it would still be hundreds of dollars I suspect.) A large bell jar (to hold the "vacuum" in) would also be hundreds I would think...
Is there no danger of atmospheric pressure crushing the glass jar? Seems like if the jar were to break you would get a clap like thunder, and that would be bad in your classroom. How much pressure is the jar able to withstand? How much pressure is being exerted onto the jar?
The jar is a very thick glass bell jar (curved on top to help withstand pressure...)
When the vacuum pump has been running for a little bit there is a difference of 1 atmosphere of pressure on the jar... :)
This is because there is no pressure on the inside, and the standard air pressure on the outside. I have no idea how much pressure the jar could handle, but I could wildly guess it would be 10's of atmospheres at least.
The acetone is really boiling. Some of the initial bubbling is removing dissolved gasses, however that wouldn't reduce the temperature of the acetone/water mixture very much.
Most of the bubbling (after the initial second or so) is actually the Acetone boiling off under low pressure. (Its boiling point is very low due to the reduced pressure.)
is the acetone really boiling or is the vacuum just removing the O2 from the acetone causing it to bubble and look like its boiling? either way very cool video!
i love your video!! And your hair is just amazing!!
nyannyandoll101 1 week ago
He is The Riddler thats why his hair is green
gunmanscotland 1 month ago
why is his hair so green?
skatedude74 4 months ago 4
@skatedude74 I like green.
sciencetheater 2 months ago
@skatedude74did he mess while playing with chemicals in his theatre ?? xD :O
alexandra19160 1 month ago
you can do this way easier buy spraying butane from a lighter refiller onto water
Lachieh923 5 months ago
@Lachieh923 True, but then you're not really "boiling" the liquid you're trying to freeze. (I could have also just put the water in the freezer, but where's the fun in that?) :)
sciencetheater 2 months ago
This video is good preparation for undergraduate thermodynamics courses where the first question asked must be, "What is my system?" This usually involves drawing a cartoon of the process and putting a dashed line around the particular thing that you're interested in. Different "sub-plots" emerge if an open system is defined (for example, all the flask contents or the liquid acetone in the flask) or if a closed system is defined (for example, all the acetone regardless of its location or state).
flyingjazz 7 months ago
Love the color of your hair.
ajitheman5 7 months ago 5
Love your videos, definitely subscribed.
Fallingangel100 7 months ago
Don't make it complicated. Evaporation is a cooling process. If something evaporates quick enough it freezes. Since it overcomes the amount of heat being absorbed
tangnatalaga 8 months ago
@tangnatalaga True, and point taken. However, rarely will you see something evaporate fast enough to freeze itself... (perhaps since solids typically sublime much slower than liquids evaporate...)
sciencetheater 8 months ago
Good video!
Dimeblack 9 months ago
Boiling point is defined as the point in which the vapor pressure of the liquid is equal to the surrounding air pressure. Vapor pressure is higher at higher temperatures, therefore at a relatively low temperature (~25 C), water and acetone will have low vapor pressures, with acetone's higher than water's(difference in intermolecular forces). Reducing pressure(vacuum) causes acetone to boil first; boiling(breaking bonds) requires energy input, which is taken from the water, causing it to freeze.
Hellamund 9 months ago
@Hellamund excellent summary, although I'm trying to avoid too many new vocabulary words with my explanation. (Yours seems more precise...)
sciencetheater 9 months ago
best hair
qwertyismypass 9 months ago
Why did you need acetone? With a good enough vacuum pump you should have been able to make plain water boil and carry away enough heat to freeze the remainder. Was your pump simply not able to drop the pressure quickly enough? In that case you could exhaust a large tank first and then open a valve between it and the bell jar to drop the pressure to near vacuum almost instantly.
ApolloWasReal 11 months ago
@ApolloWasReal Yes, I suppose that might work. Acetone just makes it all easier since it is easier to boil.
sciencetheater 11 months ago
@ApolloWasReal SCREW THE ACETONE HE HAS GREEN HAIR
Dtavs 10 months ago
@ApolloWasReal I saw this experiment successfully completed using plain water in a college chemistry class 25+ years ago. I don't remember all of the details, but I believe we had some type of material (possibly desiccant) in the bell jar also. As I recall this was to further reduce the vapor pressure. The basis of the experiment was to show that boiling is a cooling process (the liquid gives up heat) and that the vapor pressure around the liquid is what controls the boiling point temp.
wholelottahoopin 9 months ago
do u play golf on that head?
kalab00kas 11 months ago
did I see a guy with green hair?
MrTorque777 1 year ago
so thats why outer space is cold, the cold comes from water
maybe outer space is an oceon filled with water
lol lol this is something homer simpson would say
vaheedh 1 year ago
@vaheedh Not really. Being a vacuum, outer space has no temperature. But if you were to open up a bottle of water in space, it would instantly start boiling and that would carry away so much heat so quickly that it would freeze the remainder. The Apollo astronauts used exactly this method to stay cool on the moon, though it was practical for them only because they were there only a short time. Water is otherwise far too precious on the moon to let it just boil away!
ApolloWasReal 11 months ago
Title is a bit misleading.
TheCombatFetus 1 year ago
@TheCombatFetus Possibly, but you do freeze the water due to the boiling of the alcohol, so it literally IS "freezing by boiling"...
sciencetheater 1 year ago
@sciencetheater so let me see if i got this right, so you're boiling it by , instead of increasing the pressure of air in the liquid( by raising it's temperature) you decrease the pressure outside the liquid, which causes the liquid to boild, which under the lack of air pressure in the acetone the acetone absorbs heat from the water
if i understand that correctly i'm quite amazed, and i thank you for teaching me this
if i don't, please correct me
kionay 8 months ago
@kionay Sounds like you got it. Acetone boils due to low air pressure, cooling it off (perhaps think of evaporation rather than boiling), which reduces the temperature of the liquid, so the water in the liquid turns to ice.
sciencetheater 8 months ago
what caused the beaker to turn black?
anmluvr91 1 year ago
@anmluvr91 I don't think it actually turned black, it just looked that way to the camera because the ice and liquid droplets covered the inside and scattered the light passing through it.
ApolloWasReal 11 months ago
can u make an instructable video on how to dye your hair. . . im serious
IanGamil 1 year ago
@IanGamil I bleach my hair (leaving the bleach in longer than I should), then rinse and immediately put in my haircolor. I use "Directions" which I get from over in the UK. I leave that in a long time, too, then rinse. The color lasts about a week, and fades almost away in two weeks. Seems to do a bit better if I use conditioner right after coloring...
sciencetheater 1 year ago
you dont need acetone or marbles for this experiment. i tried this with just water and it works fine.
EcoDimension 1 year ago
@EcoDimension They're little rocks made out of marble, not marbles. They're there to try to prevent explosive boiling (when the liquid just blows up all at once... the chips provide a spot for the bubbles to form when the liquid degasses and boils.) The demo should work with pure water but I suspect using acetone makes it easier/more reliable.
sciencetheater 1 year ago
i LOVE ur hair
BassJokerMadness11 1 year ago
are you simply supersaturating the solution?
=. = i might be wrong. i didn't listen to the audio... i just read acetone...
jamyupsuhsuh 2 years ago
I wouldn't call it supersaturating.. I mix acetone and water, reduce the air pressure to let the acetone boil off. That removes heat from the system and makes the water freeze.
sciencetheater 2 years ago
@jamyupsuhsuh
by reducing the pressure, you reduce the amount of energy the liquid requires to break free from itself because there is less pressure holding it together.
acetone boils at a lower temperature than water at normal pressure, and the same goes for when the vacuum is applied. when the acetone boils, its higher energy molecules are flying away, leaving the colder ones behind. as this continues, more and more high energy molecules leave, hence the cooling. eventually it freezes
YellowCakeKid 1 year ago
you alchemist with your potion bottles, you! ;)
krononomikon 2 years ago
This has been flagged as spam show
Hi, good video, thats the nice thing about YouTube, people upload educational videos (under-represented on ordinary TV).
Couple of points: You said at (4.00) - You have to put heat into water to boil it. To get the Acetone to boil you have to put heat into it.
But isnt it possible to boil something by evacuating the air without adding heat?
(4.36) - You see the warm air melts the sides pretty quick.
As increasing pressure causes temperature increase, could that have caused the melting?
Zeopheus 2 years ago
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Zeopheus 2 years ago
Comment removed
Zeopheus 2 years ago
Hey! I was trying to recreate your experiment in the school last week but didn't quite succeed.
We reached the temperature of -3 or -4 degrees Celsius, but it didn't freeze. We were measuring the volumes and it seemed like some of the acetone remained in the mixture, therefore lowering the melting point. We were using the water vacuum pump (based on Venturi effect).
Could it be, that this pump was not creating enough vacuum? What pump are you using.
What is your acetone/water ratio? Thanks.
Smiks84 2 years ago
acetone to water ratio is important... try reducing the amount of acetone. My vacuum wasn't that great so I had to be careful about it as well. Make sure there is as little thermal conduction into the beaker from the base as possible. (try putting it on a piece of cork or something...
Not sure of my ratio, try a search online. It was ballpark 50/50 but maybe a tad less acetone. I tried it twice before filming...
sciencetheater 2 years ago
if you maintained the vacuum by sealing it will the vacuum keep the liquid cold forever?
onthecuttingedge2005 2 years ago
If you could keep the liquid from touching the sides of the container, then it would stay cold a long time. (Convection and conduction wouldn't add any heat...)
You'd also need to keep it in the dark, to keep radiation (another source of heat energy) from warming it up...
Bottom line, it wouldn't be practical.
sciencetheater 2 years ago
Its pretty much like pouring liquid nitrogen in water. When the Nitrogen boils, it will freeze some of the water.
anorwood84 2 years ago
Mostly, but here I'm changing the temperature at which something boils by changing the pressure. (Essentially the same, though.)
sciencetheater 2 years ago
wow never knew that was possible :D
jenna158 2 years ago
Comment removed
sekky123 2 years ago
love the hair :D
av0ka 2 years ago
So uuh, the acetone, that evaporates even easier than alcohol required temperature to boil, so it drained it all out of the water.
As same as that chill that we feel when acetone touches our body. but powered by the vacuum pump.
Nicee! 5/5
Draxis32 2 years ago
Can those kind of ice sink underwater?
deaftodd 2 years ago
I believe that was normal water ice. Which would float.
sciencetheater 2 years ago
Thanks for the comments, Alienfac32! (But please keep language PG if possible, I like to keep my video pages clean for the young'ins...)
sciencetheater 2 years ago
Nice hair... and great explanations xD
YepYepYepNo 2 years ago
Where can I get a vacuum pump and a bell jar like that? Or better yet, where can I get a kit to where I can make water freeze in a vacuum...thanks...I imagine it's expensive
saltydog78 3 years ago
Science supply places can probably hook you up with that. It is moderately pricey (hundreds of dollars) but not tremendously expensive (thousands).
sciencetheater 3 years ago
That's really interesting!
lex91793 3 years ago
Hey what's the equation for this please?
saltydog78 3 years ago
There's an equation that expresses the energy (heat) given off when a solid is formed...
You could use the heat of formation of ice and the heat of vaporization of alcohol to talk about the cooling of the liquids. That is simply: Q = mC where m is the mass and "C" would be the heat of vaporization or cooling of the respective liquid.
sciencetheater 3 years ago
im sry but the guy looks sooooo much like matthew perry
ashmaan96 3 years ago
hey I'm thinking about buying a vacuum chamber, how much does all the stuff u need cost
BigPark33 3 years ago
I'm sorry, but I'm not sure.
You need a vacuum pump (not a high end one, but it would still be hundreds of dollars I suspect.) A large bell jar (to hold the "vacuum" in) would also be hundreds I would think...
-Dr. C.
sciencetheater 3 years ago
they're good for making meruingues...i cant spell that word haha
LordTeaOfBiscuits 3 years ago
m-e-r-i-n-g-u-e-s
pronunced as mereng-ge
pazteur2007 3 years ago
Actually, it's pronounced muh-rang. Two syllables.
daichi2097 3 years ago
I would love to have you as a science teacher youre cool!
nevermindthisshit 3 years ago
Is there no danger of atmospheric pressure crushing the glass jar? Seems like if the jar were to break you would get a clap like thunder, and that would be bad in your classroom. How much pressure is the jar able to withstand? How much pressure is being exerted onto the jar?
mca0824 3 years ago
The jar is a very thick glass bell jar (curved on top to help withstand pressure...)
When the vacuum pump has been running for a little bit there is a difference of 1 atmosphere of pressure on the jar... :)
This is because there is no pressure on the inside, and the standard air pressure on the outside. I have no idea how much pressure the jar could handle, but I could wildly guess it would be 10's of atmospheres at least.
sciencetheater 3 years ago
green hair
merlilith 3 years ago
Hey, Green is awesome... it's the color of spring!
sciencetheater 3 years ago
its my favourite colour green =)
merlilith 3 years ago
The acetone is really boiling. Some of the initial bubbling is removing dissolved gasses, however that wouldn't reduce the temperature of the acetone/water mixture very much.
Most of the bubbling (after the initial second or so) is actually the Acetone boiling off under low pressure. (Its boiling point is very low due to the reduced pressure.)
sciencetheater 3 years ago
is the acetone really boiling or is the vacuum just removing the O2 from the acetone causing it to bubble and look like its boiling? either way very cool video!
leprachaun69 3 years ago
it is boiling
alwinovich 3 years ago
Nice video. Green hair day?
th55 4 years ago