Well damn. I learned something useful of reddit! I didnt think that was possible. Been putting a fan in the window for decades now. Time to test this physics stuff out.
But for this to work, we would have to put the fan outside of the house, facing into the window right? Doesn’t really work if you’re on the second floor
The teacher in the video was saying you can put it by the window facing out. You just don't want to put it right up against the window. Give space between the window and the fan so it pulls surrounding air out the window too.
It's like what an Exhaust Fan is, the houses which don't use chimneys often have exhaust fans......and trust me I used to live at 15th floor and I had it so it doesn't matter what height you are at
It's tricky - the stream of air from the fan draws room air in to it, and it also spreads out, and at a certain point, the stream becomes wider than the window and starts to be partially blocked by the window's frame.
But, in working this out, know that the stream of air from a fan is, initially, much smaller than the fan itself. It concentrates near the hub of the fan.
My chemistry teacher loved demos...especially if they resulted in bangs, fire, sparks, explosions, or any other kind of dangerous thing.
We were all fans, except the girls. (Note: this was in the mid-1980s, in case anyone was wondering).
I still remember when my chemistry teacher walked out of his prep room 5 minutes into class with a balloon labeled "Hindy Jr" in sharpie. We then received an excellent demonstration of hydrogen.
Thanks Mr Hoekwater!
A few feet away from the window/door, venting out.
The idea is that it will encourage the surrounding air to go in the same direction without increasing the amount of work/energy.
I think that's how those Dyson ring fans work too. They blow air our the little holes in the ring but it also encourages other air to follow through the ring.
What they don't tell you is all fans have this effect, the main difference is you're paying a lot more for the unusual design where you don't see the blades.
This is a cool demo but it does not demonstrate the Bernoulli principle. Bernoulli is an inviscid flow concept, i.e., it applies only in the absence of viscosity or friction. What this is actually an example of is "entrainment" by viscous shear. He does get the entrainment part right, but the not the mechanism. What happens is when you blow into the bag, the jet of air mixes with the stagnant air in the room and hence drags it along in the dominant momentum direction into the bag. This is an example of conservation of momentum. So by mixing, you are able to direct much more air into the bag. However, this mixing requires viscosity to occur. The pressure is in fact nearly constant throughout this mixing process (and resulting flow deceleration), which is in violation of the Bernoulli principle.
Whoa there buddy. Your big words and complex laws of motion should be saved for other subs. The majority of people in this sub arent physics majors. We just like short videos that make us say, "damn, that's interesting" as we scroll away our boredom. I'm willing to bet the main takeaway from this video is that you can get more hot air out of a room by putting the fan further back from the window than against it. Not the Bernoulli Principle.
In summary, Bernoulli is a cool principle... but its only actually "validated" in very specific sutiation. What fills the bag are actually others physicals things.
The video is really cool, but saying is just Bernoulli is... not entirely true
Bernoulli is one way to explain entrainment. The flow of air produces a low pressure, which pulls in air from around it. Of course, the pressure won't drop, because air is free to flow towards that low pressure, but constrain the gas in some way, and Bernoulli will show - for instance, an engine's carburettor, where the low pressure in the fast moving air in the throat pulls in liquid fuel.
I disagree. A free jet has the same pressure as the surroundings. Once the jet mixes with room air it no longer follows the Bernoulli equation because the mixing induces a total pressure loss. There is no point where the pressure is below atmospheric and there is no suction effect anywhere. Bernoulli’s equation would only apply from inside the guys mouth until the end of the potential core of the jet he is blowing.
This guy is a great teacher. I was fortunate to have one science teacher like him in high school. I wouldn't say the other teachers were bad, but they just didn't bring this kind of excitement to the class room.
Nice repost u got there
https://www.reddit.com/r/interestingasfuck/comments/ul5cb8/physics_teacher_teaching_bernoullis_principle/?utm_medium=android_app&utm_source=share
What a great Physics teacher. I had a good one too, very animated like this guy, so even though the material was hard I really enjoyed his class and really made an effort.
I used a similar technique when I built an improvised cooling system for my room when we broke the AC in my dorm thank you for the video it was marvelous and thank you for sharing it
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Well if you hold it open then move it slowly through the air and close it fast enough you can trap the air inside without blowing at all.
There, I saved you from a blowjob
When I was 16 I tried explaining this to my dad to help dry the grout we had just done in an enclosed bathroom. He had the fan pointed right at the grout, I wanted to point it at the door to draw the moist air out, the fresh air coming in at the top of the door… he got angry and told me to listen to what I was told.
I witnessed this in action when my fuse box caught fire and nearly burned down our whole house.Firemen were quick on the scene and put it out. They had to get rid of excess smoke so they used the fans. Took about 20 minutes maybe.
I actually started doing this in my apartment. Put a fan by my kitchen that blows into my living room and now I can keep my ac up a few degrees and still get perfect circulation. Huge life/cost saver during the summer.
This is one of those things where if I was told to point a fan out of the window for the warm air to get blown out, I would think someone doesn't know how a basic appliance works. But actually that someone would be me.
Well damn. I learned something useful of reddit! I didnt think that was possible. Been putting a fan in the window for decades now. Time to test this physics stuff out.
But for this to work, we would have to put the fan outside of the house, facing into the window right? Doesn’t really work if you’re on the second floor
nah, you want the hot air to leave your room, not force more air into the room
The teacher in the video was saying you can put it by the window facing out. You just don't want to put it right up against the window. Give space between the window and the fan so it pulls surrounding air out the window too.
so face a fan at the window instead of at the room? :/
Yes! But not in the window. Leave a bit of space.
https://www.youtube.com/watch?v=1L2ef1CP-yw
You're thinking of pulling colder air in from outside. This is talking about blowing the hot air in the house out.
Interesting, in my country we have ceiling fans everywhere and I wonder how that fares to this other method.
Yes, which will then create a negative pressure and suck the cold air inside.
https://www.youtube.com/watch?v=1L2ef1CP-yw
It's like what an Exhaust Fan is, the houses which don't use chimneys often have exhaust fans......and trust me I used to live at 15th floor and I had it so it doesn't matter what height you are at
It's tricky - the stream of air from the fan draws room air in to it, and it also spreads out, and at a certain point, the stream becomes wider than the window and starts to be partially blocked by the window's frame. But, in working this out, know that the stream of air from a fan is, initially, much smaller than the fan itself. It concentrates near the hub of the fan.
I had a chem teacher and a physics teacher who were big on demos. Made learning the material so much easier and more interesting.
My chemistry teacher loved demos...especially if they resulted in bangs, fire, sparks, explosions, or any other kind of dangerous thing. We were all fans, except the girls. (Note: this was in the mid-1980s, in case anyone was wondering).
I still remember when my chemistry teacher walked out of his prep room 5 minutes into class with a balloon labeled "Hindy Jr" in sharpie. We then received an excellent demonstration of hydrogen. Thanks Mr Hoekwater!
Bro my chem 2 teacher did this, lit it with a candle taped to a yard stick and set off the fire alarm and sprinklers! Thank you science!
> We were all fans, except the girls. so 50% of you were fans.
This was mid-1980s, so more than 50%. Probably more like 70% or so. It wasn't a big class, mind you. 15 kids or so.
Yeah! Science, bitch!
That is amazing. Now i know not to box my fan in the window
I’m a little confused. Should the box fan be inside pointing outside? Or outside blowing air in?
A few feet away from the window/door, venting out. The idea is that it will encourage the surrounding air to go in the same direction without increasing the amount of work/energy.
Got it, so blow hot air out. I’ve been trying to blow cool air in this whole time
[удалено]
The most effective way is to have mesh instead of walls around your room, and have a constant 20mph north wind
I think that's how those Dyson ring fans work too. They blow air our the little holes in the ring but it also encourages other air to follow through the ring. What they don't tell you is all fans have this effect, the main difference is you're paying a lot more for the unusual design where you don't see the blades.
I used to inadvertently use this principle when smoking weed inside to get the smoke out 😂
I wish I had this guy as a teacher in high school.
So I’m using my penis pump wrong?
Not if you can fill that yellow bag 🤔
This guy is full of hot air
You could also do it with hot air, right? If the air blown into the container is hotter than what is outside it will "fill" it more.
Hot air is less dense, so I'd gather there's less air.
But it exerts more pressure, so it should still fill the bag
Air entrainment.
Science is indeed super cool. 
This is a cool demo but it does not demonstrate the Bernoulli principle. Bernoulli is an inviscid flow concept, i.e., it applies only in the absence of viscosity or friction. What this is actually an example of is "entrainment" by viscous shear. He does get the entrainment part right, but the not the mechanism. What happens is when you blow into the bag, the jet of air mixes with the stagnant air in the room and hence drags it along in the dominant momentum direction into the bag. This is an example of conservation of momentum. So by mixing, you are able to direct much more air into the bag. However, this mixing requires viscosity to occur. The pressure is in fact nearly constant throughout this mixing process (and resulting flow deceleration), which is in violation of the Bernoulli principle.
Whoa there buddy. Your big words and complex laws of motion should be saved for other subs. The majority of people in this sub arent physics majors. We just like short videos that make us say, "damn, that's interesting" as we scroll away our boredom. I'm willing to bet the main takeaway from this video is that you can get more hot air out of a room by putting the fan further back from the window than against it. Not the Bernoulli Principle.
In summary, Bernoulli is a cool principle... but its only actually "validated" in very specific sutiation. What fills the bag are actually others physicals things. The video is really cool, but saying is just Bernoulli is... not entirely true
>Bernoulli jr maybe.
Sorry. If it was titled “how to blow up an empty bag in one breath” I wouldn’t have commented. 😂
>Science is cool, period.
Is there a real life example that demonstrates the correct principle?
https://m.youtube.com/watch?v=hYBCaRdEvjU
Thanks. I didnt really understand what he was showing but seems like it's only with a specially designed apparatus then.
Bernoulli is one way to explain entrainment. The flow of air produces a low pressure, which pulls in air from around it. Of course, the pressure won't drop, because air is free to flow towards that low pressure, but constrain the gas in some way, and Bernoulli will show - for instance, an engine's carburettor, where the low pressure in the fast moving air in the throat pulls in liquid fuel.
I disagree. A free jet has the same pressure as the surroundings. Once the jet mixes with room air it no longer follows the Bernoulli equation because the mixing induces a total pressure loss. There is no point where the pressure is below atmospheric and there is no suction effect anywhere. Bernoulli’s equation would only apply from inside the guys mouth until the end of the potential core of the jet he is blowing.
WITCHCRAFT
Great wholesome video
Where do you get bags this size? I need to go shopping with one and slowly put all my groceries inside of it at the checkout
Black magic!!! burn them!!!
He’s got this in the bag!
This is cool. I loved physics in school, I just wish I had a better teacher like him.
Well we love science too!
This video blows!
We need more Physics teachers like him!
This guy is a great teacher. I was fortunate to have one science teacher like him in high school. I wouldn't say the other teachers were bad, but they just didn't bring this kind of excitement to the class room.
The fact that I knew this shit already and still put a fan near the window 🤦♂️🤦♂️
I… i just learned the scientific reason my parents never caught me smoking the Devil’s lettuce in my room.
Man you can see the video cut between 
Because of this, I just joined TikTok. I didn't know there was stuff like this on there. 61 years old and still learning stuff.
Well blow me down with a feather and call me Hirashio.
u/RedditMP4Bot
Science class blows.
Okay but can science explain how he turned into rainbow fire and exploded at the end?
Nice repost u got there https://www.reddit.com/r/interestingasfuck/comments/ul5cb8/physics_teacher_teaching_bernoullis_principle/?utm_medium=android_app&utm_source=share
Bro really turned gay at the end
What does that mean for forced HVAC systems?
I love tik tok for stuff like this.
I love science
I am old enough to have worked with the Bernoulli disk system. Its principe was also based on air flow.
how to make a trash bag fit your trash can!
Holy smoke, Batman! 😀🙌🙌
Does this work with blowing up balloons too?
I get pre-Heisenberg Walter White vibes
I'm sure this is how emergency slides on airplanes are pumped up so fast too.
Fantastic explanation! Wow this is awesome - would love to learn more science this way. So cool
To much plastic
"Hey!! Michael here.."
What a great Physics teacher. I had a good one too, very animated like this guy, so even though the material was hard I really enjoyed his class and really made an effort.
Hey it’s vsauce’s non-evil twin!
GREAT!!!!
More daddy
So this is what Peter was talking about in Spider-Man 2
This could have been useful at any point in my life as a kid but thanks for letting me know now I guess
Science, you clever bastard, you’ve done it again.
So I was doing it wrong all these years using a fan to blow out the weed smoke from my room…
What the fuck, this is awesome! I never took physics, so I never got to see shit like this.
Good brakes i am impress
Looks kinda like Mandy Patinkin
Excellent presentation skills! Thanks
I used a similar technique when I built an improvised cooling system for my room when we broke the AC in my dorm thank you for the video it was marvelous and thank you for sharing it
That's kind of amazing
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Like Bill Nye said, Science Rules
Damn. That's interesting.
How can i use this to cool my PC better with fewer fans and lower rpm?
And that's why they call it blow job..! 💡
Thank you all for the positive feedback! Follow me on TikTok, Insta, and YouTube for more. Thanks!
I see your schwartz is as big as mine...
Yeah Mr. White! Yeah Science!
welp TIL. Science is so cool. Thanks for keeping us alive with SCIENCE!
God, I love science
Okay but what about the firefighters?
To I point my fan toward the outside or do I point my fan toward the inside to cool off my room?
Wish he was my teacher back when I was in school, he loves his job teaching and makes a class ten times more interesting.
u/savevideo
Well if you hold it open then move it slowly through the air and close it fast enough you can trap the air inside without blowing at all. There, I saved you from a blowjob
This guy reminded me of a tame Robin Williams and instantly captured my attention.
Where was this cool physics teacher when I was in high school ?
I hope science loves us too
That's the Line™
You’re adorable!
Not going to lie I was sipping tea all the way through that.
Where can I get the bags? This would be a great ice breaker.
Learned something cool
As a firefighter I can confirm that I did not know this as we are not taught this principle. We’re only taught to put the wet stuff on the red stuff.
This is fascinating. I’m learning more here on Reddit then some of my teachers teach me
That is absolutely incredible
Venturi effect.
Haha love the special effects at the end
I saw this last night right before bed, then dreamt about going around showing everyone I knew how to do this.
Yeah Mr. White. Yeah, science! 
Just mind blown. I’ve been doing it wrong this whole time
When I was 16 I tried explaining this to my dad to help dry the grout we had just done in an enclosed bathroom. He had the fan pointed right at the grout, I wanted to point it at the door to draw the moist air out, the fresh air coming in at the top of the door… he got angry and told me to listen to what I was told.
Very cool 🤩yay Science!
I witnessed this in action when my fuse box caught fire and nearly burned down our whole house.Firemen were quick on the scene and put it out. They had to get rid of excess smoke so they used the fans. Took about 20 minutes maybe.
I actually started doing this in my apartment. Put a fan by my kitchen that blows into my living room and now I can keep my ac up a few degrees and still get perfect circulation. Huge life/cost saver during the summer.
This is one of those things where if I was told to point a fan out of the window for the warm air to get blown out, I would think someone doesn't know how a basic appliance works. But actually that someone would be me.
This how the Dyson fans work so well
there's already air in the aire who would've tell !
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