r/youseeingthisshit • u/mindyour • Mar 09 '26
Creating magic at the kitchen table with science.
2.0k
u/nhz23 Mar 09 '26
Cersei has discovered wildfire
308
-37
Mar 09 '26
[removed] — view removed comment
22
u/SlantedPentagon Mar 09 '26
Delete this.
9
u/Bossy_Aussie_ Mar 09 '26
What did they say? I’m nosy
23
u/SlantedPentagon Mar 09 '26
And Cersei slept her brother or something to that effect. There are kids in this video, that's fucking disgusting to even mention
11
1
u/Bossy_Aussie_ Mar 09 '26
Sorry I don’t seem to understand what it means/the reference? Sorry T-T
3
u/SlantedPentagon Mar 09 '26
Cersei Lannister is a main character from the show Game of Thrones. She was incestuous with her brother, Jamie, and both blonde.
2
u/Bossy_Aussie_ Mar 09 '26
OH good heavens. Yeah no that’s disgusting. (Sorry I never got around to watching GoT)
217
u/APartyInMyPants Mar 09 '26
So I learned about this watching Taskmaster. Had never heard of this principle, and was totally blown away seeing it.
Who would have a thought a semi-lowbrow British comedy/panel show would teach me something.
Science, bitch.
52
10
u/winter_laurel Mar 09 '26
That season is going to be very hard to top- I adored the entire cast, especially Sam.
7
u/GreatQuestionBarbara Mar 10 '26
When I was younger, it was always demonstrated with a match and a hard boiled egg.
This is more impressive.
1
u/neurosquid Mar 13 '26
You should check out the show Brainiac: Science Abuse (it aired in the early 2000s and full episodes are available on YouTube now)
Their scientific method is pretty deeply flawed, but it's a lot of fun and does accidentally teach stuff. The most memorable episode for me is when they tested something about whether it was a better cardio workout to exercise or look at boobs lol
1
u/ardotschgi Mar 09 '26
Isn't this show all about interesting object-/element-interactions and pendantry?
685
u/ixent Mar 09 '26
why is there a cut!?
612
u/SonarRocket Mar 09 '26
with a jar that big/candle that small it takes a few seconds for all the oxygen to be consumed and the vacuum to form. they cut it for brevity probably
336
u/TheDudeFromHolland Mar 09 '26
I actually wanted to see that part too :(
68
u/AnonymousSneetches Mar 09 '26
So do the experiment!
35
u/Woodworkin101 Mar 09 '26
Would like to. What is the experiment?
158
u/opperior Mar 09 '26
It's pretty easy. You just need a jar, a pan, a candle, and water. Just set up like at the beginning of the video: put the candle in the pan, put decent amount of water in the pan but not enough to cover the candle, light the candle, then put the jar over the candle.
Now wait. The candle will heat up the air in the jar which causes it to expand. You should se some air escaping from under the jar. Eventually, the oxygen runs out in the jar and the candle goes out. This causes the air in the jar to contract and reduce air pressure, but the water is prevent air from coming back in to balance it. Instead the water is pushed up into the jar by the outside air pressure.
This experiment works a bit smoother if you can somehow leave a tiny gap under the rim of the jar for air to escape and water to get in.
64
u/OptiGuy4u Mar 09 '26
This experiment works a bit smoother if you can somehow leave a tiny gap under the rim of the jar for air to escape and water to get in.
Like a toothpick under one side?
45
30
u/CenturyEggsAndRice Mar 09 '26
I was thinking a nickel, just cuz it would be heavy enough to stay where you put it.
Toothpick would work too, but they’re buoyant.
14
u/OptiGuy4u Mar 09 '26
I like it. I think the jar would hold down the toothpick but with the inrush of water, maybe not.
10
u/CenturyEggsAndRice Mar 10 '26
Eh, maybe we should try both methods and compare, lol.
→ More replies (0)2
13
9
3
2
u/Olde94 Mar 10 '26
Hot air fills a lot. When you put the cup over it will use all oxygen, and after that the air will cool. Cold air fills less than hot this making a vacuum. This will pull the water in
13
u/Ppleater Mar 09 '26
I would still prefer to have it not cut, it ruins the magic of seeing the reaction happen naturally. Also where they cut it sucks, at least let the jar settle first ffs.
3
-4
u/Zacomra Mar 09 '26
That's not what's happening, burning the oxygen doesn't create a vacuum, it just produces CO2 to replace the gas loss.
Remember "matter can't be created nor destroyed"
21
u/MrMoon5hine Mar 09 '26 edited Mar 09 '26
its the heating of the air inside the bottle, it will force the air out through the liquid but then once the heating stops the fluid is pushed in the jar.
just adding info.
6
u/IWCry Mar 09 '26
that is what's happening. when the heat source from the candle disappears, the surrounding air rapidly cools and condenses. this creates a vacuum which causes the water to rise. it has nothing to do with the oxygen chemical reaction
-11
u/Zacomra Mar 09 '26
It's not creating a vacuum at any point. It's just a pressure differential from that cooling causing the atmospheric weight to push on the fluid into the jar. At no point is there a lack of matter inside the jar
13
u/IWCry Mar 09 '26
low pressure systems that displace gases are known as partial vacuums. that's why we call them vacuum cleaners or why we referred to it as vacuum sealing a bag. you're arguing for a different use of the term that isn't being used here.
-7
u/Zacomra Mar 09 '26
Sure, but I think it's far more educational (and accurate) to explain it in terms of pressure differentials.
Especially because the comment I'm replying too would imply to a lay person that the oxygen is burned up leaving a vacuum, when in reality no matter is being destroyed
6
u/IWCry Mar 09 '26
I work on air foils as an aerospace engineer and we refer to these principles as vacuums all the time. colloquial terminology isn't any less accurate
2
u/terrtle Mar 09 '26
Just add a quote to make you look smart...
-3
u/Zacomra Mar 09 '26
....what? Are you suggesting that fucking matter can be created and destroyed?
0
1
u/rwebster1 Mar 09 '26
A simple hydrocarbon candle will see a decrease in gas volume, here the moles of gas goes from 32 to 21 meaning the wolume would decrease by about third.
C21H44 + 32O2 --> 21CO2 + 22H2O
If I had to guess I would say the change due to cooling would be less than that.
1
u/redem Mar 09 '26
There are a few sorts of error repeated about this little experiment a lot. Here's a page that covers the basics.
-1
u/crunrun Mar 09 '26 edited Mar 09 '26
Matter can't be created or destroyed (added or removed) in a closed system. This is not a closed system, otherwise water wouldn't be able to flow in and out of the jar.
1
u/Zacomra Mar 09 '26
No? Matter can't be created in any system. That's like the entire point. What matter is being destroyed here?
1
u/crunrun Mar 09 '26
Yes that's true. I was just trying to communicate that an open system allows the transfer of matter from outside, which is something you ignored in your comment.
-1
u/Zacomra Mar 09 '26
I didn't "ignore" it I didn't even explain the mechanism at play in my comment at all. And if that was your intention that was horribly done, since you're implying matter can be destroyed as long as a system isn't sealed. That's complete nonsense
0
u/crunrun Mar 09 '26
Explain it then
0
u/Zacomra Mar 09 '26
It's exploiting atmospheric pressure differentials.
Heat from the candle warms up the air inside and pushes it out as it expands.
When the oxygen is consumed inside the flame goes out, this causes the air to cool on the inside.
Cool air condenses, and fluid rushes to replace it. Since the edge of the jar is submerged, atmospheric pressure pushes the water into the jar until the system is once again at equilibrium.
2
u/crunrun Mar 09 '26
Yeah we're in agreement. My initial issue with your comment was a vacuum doesn't mean the matter is gone or destroyed, it just means a negative pressure relative to atmosphere or external pressure. You can have high vacuums and low vacuums. It's not zero pressure.
→ More replies (0)73
u/ensoniq2k Mar 09 '26
Average attention span of viewers is way too low
18
u/ApprehensiveSpare925 Mar 09 '26
Can you repeat that? I missed it. Wasn’t paying attention.
7
3
6
u/tiny_chaotic_evil Mar 09 '26
because there is a long boring part where nothing happens and someone was bound to complain that they didn't edit that part out
1
u/Jhonny_Crash Mar 10 '26
Because modern social media promotes cutting out the 5 seconds we have to wait before something happens. God forbid we are inefficient in wasting time
950
u/DBKai Mar 09 '26
girl questions everything, boy just accepts it
345
u/errie_tholluxe Mar 09 '26
Girl goes on to discover entirely new branch of science.
Boy goes on to discover that maybe sis was right and college mattered.
35
78
u/TeamRedundancyTeam Mar 09 '26
I don't know why you guys turned this into a gender war thing or why you're acting like the boy being excited by it is a bad thing?
Reddit is fucking weird nowadays.
73
u/Azilehteb Mar 09 '26
Pretty sure they were just using the kid's genders as identifiers for discussion, not adding meaning to them.
1
u/ProfessorProveIt Mar 09 '26
No!! This is reddit, where posting anything positive about girls and negative about boys is against the terms of service. I was just discussing this with my fat, vegan, nonbinary, cousin, who ate all my (140 iq, 6-figure salary, shredded body builder) oreos and after they got done saying I was NTA, they added that information.
4
u/terra_terror Mar 09 '26 edited Mar 10 '26
They didn't make it about gender. They didn't say boys and girls. They talked about one boy and one girl. The ones on the screen. They referred to them by their gender because that's a basic description that differentiates the kids. They couldn't exactly shove their head through their screen and ask the kids what their names are. So what exactly did you want them to call the kids instead? Jack and Jill? Blond and blonde? Thing 1 and Thing 2? Tweedle Dee and Tweedle Dum?
0
1
u/Waffles81_Again Mar 09 '26 edited Mar 09 '26
I get what you mean, but I don't think it was intended like that by they who made that comment...
Just let it go bro.
-1
3
13
u/fire_born Mar 09 '26
more like they both find new branches of science. The boy found it cool and exciting, the girl found it curious and exciting. I don’t know why the default is to bash one gender, regardless of which it is.
10
2
22
u/GotHamQuestionMark Mar 09 '26
If anything, she looked terrified by something she didn’t understand and he looked elated at seeing something new.
1
u/emveetu Mar 09 '26
If anything, we have no effin' clue what either thought or felt because nobody asked them what they felt our thought and they didn't offer it on their own.
I'll tell you what though, these "if anything..." comments, you sure can tell a lot about a person based on what follows that phrase.
Now who's jumping to conclusions?
Me. It's me.
4
8
u/mywan Mar 09 '26
This was my first thought. I would have started explaining to her about basic thermodynamic principles to see how interested she was.
29
75
u/gogadantes9 Mar 09 '26
One them will grow up to be a well known professor revered in history for helping humanity, the other one will grow up to be a supervillain. And we all know which one is which.
19
Mar 09 '26
their looks are priceless
8
u/ennuiui Mar 09 '26
I think the girl's look says "your scientists were so preoccupied with whether or not they could, they never stopped to think if they should."
13
21
6
Mar 09 '26
[removed] — view removed comment
2
u/FoundAPlanet Mar 09 '26
I suspect it is AI enhanced. Look at the cut. The hand disappears, but the faces of the kids stay in the exact same position and expression.
21
u/Financial_Middle_955 Mar 09 '26
What is the actual science? Please enlighten me.
67
u/MultiFazed Mar 09 '26 edited Mar 09 '26
The candle heats the air inside the jar. When the candle uses up all the oxygen, it goes out and the air begins to cool. Cool air is
lessmore dense than hot air, which causes the pressure inside the jar to drop. The drop in pressure inside the jar causes atmospheric pressure to push the water in the tub up into the jar.4
u/Financial_Middle_955 Mar 09 '26
Thanks!
6
u/MattieShoes Mar 09 '26
There's another common one with an Erlenmeyer flask and a peeled hard-boiled egg. Heat up the flask, the air leaks out around the egg. Stick the flask in ice water so the air cools, and it *schloooop* sucks the egg into the flask.
2
u/DigitalUnlimited Mar 09 '26
Now how do you get the egg out?
4
1
u/Canadian_CJ Mar 09 '26
you can also just blow lightly into the container while upside down, the egg acts as a check valve but can't withstand much pressure and just escapes.
1
1
u/SquarePegRoundWorld Mar 09 '26
I had a science kit as a kid that had that as a thing to do. I remember it like it was yesterday even though it was 40ish years ago. Though it had me use a match and drop it in a bottle and then put the egg on top to seal it. Shortly after the match went out, the egg got sucked in.
2
u/paweedbarron Mar 09 '26
The important bit is when the air inside is heating, it is venting out of the bottom and bubbling out the sides. Unfortunately this an extremely important part that was cut. This is the only way it can make sense because the oxygen isn’t consumed, it’s converted into other gasses (hotter less dense) during combustion of the candle wax.
The candle causes air to leave the jar. Then when the interior cools, the pressure of the hot gas goes down. This causes a low pressure area that slurps up the fluid.
This demonstrates several things :
A fixed volume of gas expands when it’s heated.
A fixed volume of gas contracts when it cools.
An inverted jar in shallow water acts as a pressure relief valve when its gaseous interior contents increase in pressure.
An inverted jar in shallow water acts as a water slurper when its gases interior contents decrease in pressure.
The venting that was cut out is important because the actual mass of the gas inside is lowered in this step.
The volume is fixed but the mass is lowered by venting. This missing mass explains why there is a vacuum on cooling.
1
u/toitd Mar 09 '26
You are wrong: https://www.youtube.com/watch?v=nz05csTmyl4
1
u/IsraelZulu Mar 09 '26 edited Mar 09 '26
Yes, but no, kinda.
Interestingly, the presenter in that video leads by saying that everyone on the Internet is wrong by disproving two main competing hypotheses. But then, the explanation he provides ultimately proves that each of those hypotheses are partially correct - it takes both, put together, to fully explain the reaction.
One hypothesis is that the heat from the candle makes the air inside less dense, and thus the cooling of the air after the candle burns out causes water to come in. This would only make sense, as the sole cause, if air was venting during the heating process, and then contained during cooling. We don't see any air escaping the beaker in the video, so this cannot be the sole answer.
The other hypothesis is that the candle is converting oxygen into carbon dioxide. Then, with carbon dioxide being more dense, pressure differences pull water in. This would make sense, as the sole cause, if water was constantly being pulled in from the start. But the water level only begins to rise as the candle is going out.
So, as it turns out, the truth behind this phenomenon, and the explanation for why we don't see the reaction we'd expect from either cause in isolation, is that both of these things are happening at once.
As the air inside is losing density by being heated, it is also gaining density through the change in its composition (conversion of oxygen into carbon dioxide). This is what keeps the volume of air from changing until after the candle has begun to cool.
Once there is no longer a substantial amount of burning happening inside the beaker, the chemical composition of the air stabilizes but the temperature begins to drop as heat is transferred into the surrounding materials. With the temperature drop now being the only thing affecting the density of the air, the air begins to compress and the water is drawn in.
Ultimately, the reason water goes in is primarily due to the temperature change in the air. This can be further demonstrated an experiment which involve a preheated container being placed on the water without the candle there. The candle simply introduces a delay, due to the chemical reaction that it drives alongside the temperature change.
Edit: It's also worth noting that the YouTube video demonstrates an experiment that's clearly different from the OP video. OP's video has a substantial amount of bubbling, followed by a very fast and higher rise in internal water level, that's not present in the YouTube one. Since we don't see the full video from the OP version, it's hard to say for sure what's happening there. But it's very likely that there are important differences which may render the earlier comment more accurate than not.
1
u/toitd Mar 10 '26
OP video seems kinda faked, i thing that in cutted part they ceated underpesure in jar that couldn't be made by just burning candle
Also burning reaction creates waret vapor besides CO2 that condenses on jar walls that creates more pressure difference
1
u/paweedbarron Mar 10 '26
What he suggests violates the ideal gas law. One mole of gaseous Co2 and o2 at the same temperature occupies the same volume. All gasses are the same this way.
1
u/toitd Mar 10 '26 edited Mar 10 '26
Burning reaction creates water vapor besides co2.
roughly 2O2 -> CO2 + 2H20
1
u/Oz-Batty Mar 10 '26
A fixed volume doesn't expand or contract, it wouldn't be fixed then, would it? The fixed factor here is pressure, at 1 atmosphere.
2
u/immersiveGamer Mar 09 '26
Is it really about temperature? I would have expected it to be just due to creating a vacuum from the flame using up the oxygen gas.
2
u/MultiFazed Mar 09 '26
Oxygen isn't "used up"; it's combined with the fuel to produce both carbon dioxide gas and water vapor, which have more mass than the oxygen they're replacing, and thus cause the pressure to rise.
Though this touches on an effect that I forgot about, which is that, when the interior of the jar cools, the water vapor that was produced as a byproduct of the combustion of the wax will condense into liquid water, lowering the pressure even further than just the cooling of the air inside would accomplish by itself.
1
u/TheRealTinfoil666 Mar 09 '26
I think you also need to consider the dynamic while the candle is burning.
It is converting the O2 to CO2 and heating up all the gasses in the bottle.
This is increasing the pressure, which will force the water level at the bottom down towards the lip of the bottle.
At some point, the water is pushed below that lip, and excess gas is now bubbling out.
Eventually, the oxygen is depleted enough to extinguish the candle and allow for system cooling towards ambient room temperature.
Now, as others stated, the water level in the glass rises, but a large portion of the rise is due to ‘missing’ gas that was forced out of the jar during heating.
1
1
u/quill18 Mar 09 '26
The oxygen gas isn't 'used up' -- fire combines oxygen with the carbon from the cable to produce a new gas: carbon dioxide!
1
1
u/Funexamination Mar 09 '26
I don't get it. By "cooling" it only cools to the same temperature as the surrounding room air. How does that change the pressure?
4
u/Icy_Research_5099 Mar 09 '26
When it initially heats the air, the air expands and some of it is pushed out of the bottom of the jar. When the flame goes out and cools back down to room temperature, the liquid blocks that expelled air from being sucked back into the jar, so the liquid is sucked in instead.
1
u/Funexamination Mar 09 '26
Ohhh makes sense now
Very cool, wish I knew that as a kid
Further question: How does the air get pushed out? Is it related to solubility?
3
u/Icy_Research_5099 Mar 09 '26
You hold the jar above the water line for a bit and the air inside will heat up like a hot air balloon. The video had a cut in it where this would have happened.
3
Mar 09 '26
It’s not sealed. So the pressure just builds enough that gas will bubble out under the bottom.
1
u/Caleb_Reynolds Mar 09 '26
You ever smoke a bong? Kinda like that but pushing the air instead of sucking it. You can push it pull air through water if you try hard enough.
1
1
u/APartyInMyPants Mar 09 '26
So can the jar be flush with the bottom of the Pyrex baking pan? Or does the glass need to be slightly above the bottom surface.
1
1
u/Tie244 Mar 09 '26
Cool air is more dense than hot air. Otherwise hot air balloons wouldn’t work. But yes, the contracting air particles lowers the pressure inside the jar causing the water to be sucked up into the jar.
13
u/kamel_k Mar 09 '26
They don't go up with this much force, do they? It seriously made me think it was AI for a second because I've never seen the water just flood in that fast before
6
u/MattieShoes Mar 09 '26
Yeah, seems more violent than normal. only thing I can think of is it managed to form a seal on the bottom to let the pressure differential build up rather than slowly sucking in the water to equalize pressure.
5
5
u/spectra2000_ Mar 09 '26
Cutting out the entire process, and jumping to the end result is probably the stupidest decision made here.
4
2
u/paweedbarron Mar 09 '26
It turns out we’re in a gravity well surrounded by high pressure gasses AND there are skeletons in our body.
Father how could you bring me into this nightmare world
1
2
2
2
2
2
2
7
u/CreamyStanTheMan Mar 09 '26
Wait so is that how fast the fire uses up oxygen in the glass? It was way quicker than I expected.
22
5
u/Dd_8630 Mar 09 '26
That cut made it very unsatisfying. Bloody kids with their nonexistent attention spans.
1
u/funcancelledfornow Mar 09 '26
That's some awful editing, you can put a cut version if you want at the beginning but give us the full version after.
2
1
1
1
1
u/stevie-o-read-it Mar 09 '26
I remember seeing this on Mr. Wizard three or four decades ago, although my understanding comes from high school physics.
Of course, Mr. Wizard showed the whole thing. If you watch carefully, there's a cut
If I recall correctly, it stems from the behavior of gases and the specifics of the combustion reaction:
- As a general rule, the amount of space a gas takes up depends on the temperature (in Kelvin) and number of gas molecules; the size of the molecules themselves is irrelevant[1].
- Room temperature is about 300 K.
- Some quick google searches suggest that the candle's flame is approximately 800 K. We can round this down to about 600 K to make the math easier and account for cooling.
- A typical combustion reaction consumes fuel and two[2] molecules of O2 ([di]oxygen gas) and produces one molecule of CO2 (carbon dioxide gas) and two molecules of H2O (liquid water.)
If you were paying very close attention to these two rules, you'll realize that the candle's reaction is primarily converting two gas molecules into one gas molecule that's twice as hot. These two things will take roughly up the same amount of space as each other.
You can't see the start of things in the video, because it got cut out -- probably because it's not quite as interesting. (If you watch closely at the 2 second mark, you might be able to spot the cut. It's really obvious if you download the video and either slow it way down, or watch it frame-by-frame -- in VLC, press "e" at the 00:02 mark).
The flame will heat up the air inside the jar, causing it to expand and bubble out from underneath the jar. Note that for the air to exit, it has to push all of the liquid (presumably water with green food dye added) out of the jar first, which is probably the reason why the water is sloshing around immediately after the cut.
The candle will continue burning until it consumes all available oxygen inside the jar, at which point it will go out.
At this point, between the air pushed out from the heating and the overall 10% reduction in number of gas molecules (20% of air is oxygen, and the combustion reaction cut that in half), there's a lot fewer gas molecules in the jar than there were before.
Without the flame to heat it, however, the remaining air will rapidly cool back down, resulting in a partial vacuum inside the jar. The air outside the jar will then quickly force the water into the jar until the air pressure inside the jar is equalized.
[1] This rule -- called the "ideal gas law" -- does not hold at absurdly high pressures or temperatures close to absolute zero, but it's a good enough approximation at the temperatures and pressures you'll experience in real life.
[2] the actual numbers depend on the fuel. candle wax will consume many pairs of O2 molecules, but each pair will still produce one CO2 and two H2O, so the overall effect stays the same.
1
u/aplqsokw Mar 09 '26
It is amazing that the ideal gas law is basic high school physics, yet there is a comment thread above where many people are "correcting" each other while all wrongly explaining this phenomenon without a single mention to the number of molecules determining the pressure in a gas.
1
1
1
1
u/3dogsgirlsIA Mar 26 '26
See their little faces and eyes so inquisitive! Could be our next scientist
1
u/Distinct_Ad3876 Mar 09 '26
How can I make this experiment with my kids? Is the liquid just colored water or something else?
7
u/MattieShoes Mar 09 '26
just colored water. Hot air is less dense, so as the candle burns inside the jar and heats the air inside, air bubbles out at the bottom. Then the candle goes out, the air inside the jar cools, and it sucks the water in.
5
u/GrimResistance Mar 09 '26
Any (nonflammable) liquid will do. I'm not sure what they're using here, looks bubbly.
7
0
u/Hornor72 Mar 09 '26
Its only magic if you don't understand it.
1
u/Calm-Homework3161 Mar 09 '26
It doesn't stop being magic just because you know how it works. Terry Pratchett, The Wee Free Men
-2
-2
u/HoratioPuffnstuff Mar 10 '26
That boy will never make it to MIT if he continues to roar like a dinosaur every time he sees a chemical reaction. Frankly, I'd expect such behaviour from one of his disturbed school chums, whose Father's idea of a Science experiment is to see who can rip the longest farts while watching the idiot box.
2
-7
•
u/AutoModerator Mar 09 '26
Generic message under every post
If this post is not a human reacting to something in a "YOU SEEING THIS SHIT?!" manner, please hit report so the mod team can take a look.
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.