The Venturi effect

[@MaxSebastianMayer]

My dude here from explaining the venturi effect to building a flamethrower

[@robindunn7248]

I am really grateful for this video. I am taking a course that just said, "make a venturi". So I googled it, wiki'ed it, and was still lost. A video is worth a trillion words. Well demonstrated. Thank you.

[@thomhong]

I have never seen this topic explained like this before. The visuals you create are VERY clear and informative.

[@KeenPeachy12]

What a great video. I'm studying for the MCAT and having all these visual examples so much more effective than reading about in a text book.

[@musicrocksfu]

lol cam here after CP FL2

[@monav2686]

@@musicrocksfu same tho

[@charlizard5901]

musicrocksfu woah holy shit same

[@JAGV845]

@@musicrocksfu same lmaoo

[@reenanwa]

Fl2 question 25?

[@matthiaswandel]

Actually, I filmed this during the drought. I hosed down the grass and the trees around before doing the flame experiments.

[@adamtain7627]

So basically does this Venturi effect help fan out for example fuel to help spread it out more easily if it’s either for liquid or gas fuels?

[@GarageWoodworks]

The principle is also used in old chemistry labs to provide vacuum for rotary evaporators. An adapter is connected to a faucet to create the vacuum. Wastes a good deal of water in the process.

[@matthiaswandel]

The opening on the metal tube is about 1.5 mm in diameter. The numbers I quoted were to illustrate, I have no idea what the actual speed was.

[@killer-of-mufasa9246]

Should have used this on the wasps

[@AzureOnyxscore]

or spiders...

[@genmasaotome3503]

That's what I was about to say...

[@CorinGatwood]

what have the spiders done?

[@stupidsmartmonkey]

+LemonSpy_ we are used to them. Everyone that visits has a heart attack

[@nou4898]

369 likes

[@mebezaccraft]

I never knew woodworkers could be this badass

[@thedge7]

Adding fire is always good.

[@pocket83]

A sandblaster might have been worth mentioning. That was the first thing that came to mind for me.

[@hardwirecars]

jet engin for me its how the after burner works if im not mistaken.

[@schwuzi]

For me it's a carburetor

[@matthiaswandel]

It's specifically much more the venturi effect than the bernuli principle. The bernulli effect is about energy conservation, whereas this is about mixing of air streams. That's why a vernturi pump is a venturi pump, not a bernulli pump.

[@SamHaugen]

Excellent visual display of the Venturi effect. Just what I needed!

[@matthiaswandel]

The Bernoulli equation is based on conservation of energy, and energy is not conserved when fluids of different speeds mix.

[@Johny40Se7en]

You know the bucket of water with the hose pipe experiment you demonstrated, if you swapped the hose pipe with an airline like you used for the saw dust, I'm guessing that's what you're explaining? Water's way more dense than air, so the energy will dissipate and not push the water out as quick as water to water would... makes sense.

[@1islam1]

@@Johny40Se7en ⚠️ God has said in the Quran: 🔵 { O mankind, worship your Lord, who created you and those before you, that you may become righteous - ( 2:21 ) 🔴 [He] who made for you the earth a bed [spread out] and the sky a ceiling and sent down from the sky, rain and brought forth thereby fruits as provision for you. So do not attribute to Allah equals while you know [that there is nothing similar to Him]. ( 2:22 ) 🔵 And if you are in doubt about what We have sent down upon Our Servant [Muhammad], then produce a surah the like thereof and call upon your witnesses other than Allah, if you should be truthful. ( 2:23 ) 🔴 But if you do not - and you will never be able to - then fear the Fire, whose fuel is men and stones, prepared for the disbelievers.( 2:24 ) 🔵 And give good tidings to those who believe and do righteous deeds that they will have gardens [in Paradise] beneath which rivers flow. Whenever they are provided with a provision of fruit therefrom, they will say, "This is what we were provided with before." And it is given to them in likeness. And they will have therein purified spouses, and they will abide therein eternally. ( 2:25 ) ⚠️ Quran

[@matthiaswandel]

Pelikan, with the regular blue Pelikan ink. Pelikan makes the best fountain pens. Plain, simple and relatively inexpensive, but they write way better than expensive Parker pens.

[@ercost60]

You sir, are an artist and genius. I thoroughly enjoy your channel. Every video is a fascinating gem. Thank you for sharing your many varied creations.

[@nsideoutn8439]

This video is great. I think I’ll check out more of his.

[@matthiaswandel]

A Pelican fountain pen. Bought it in Germany Nice no nonsense fountain pens, work way better than the parker fountain pens (which are mostly for status)

[@DarkSparkCannabis]

This is a fantastic video. I learn best with examples, and when learning a new concept, displaying several examples really paints the picture. Thank you.

[@BYSMA4th]

Have been looking around for a good explanation of the Venturi effect since I've heard sports cars use it...this has been the most intuitive explanation I've found so far. Thanks! :)

[@AkiraKeiKyo]

Thank you good sir for demonstrating the venturi effect and giving a thorough explanation. It make a lot of sense now with what I am learning in the lab :)

[@LividLeon]

The best explanation out of all the videos I saw. I like how your video is simple and to the point.

[@jrcahoon]

Great video! Mattias, you have a talent at clearly explaining concepts. I would love more physics videos.

[@matthiaswandel]

For ceramic glazing, you wouldn't want to use a real spray gun. That stuff is thick and abrasive, so the straw is an excellent idea.

[@matthiaswandel]

I wanted to try it with sawdust, but it's really hard to ignite. I think if I had a bonfire to spray it into, it might work.

[@snowsurfr]

This is awesome! Love the thorough explanations, diagrams, and most of all the demonstrations. Subbed.

[@edwaggonersr.7446]

Your curiosity about just about everything is refreshing.

[@sayedpritom]

This is the best video I have found on the Venturi effect

[@EliotTruelove]

I know this is an old video, but could the exhaust port of a vacuum be hooked up to the intake port of a vacuum to increase the suction effect using the Venturi effect? Or is there diminishing returns?

[@kck-kck879]

No

[@matthiaswandel]

Thanks! People know about bernoulli, and think it applies to all flow situations. It doesn't.

[@ndxs]

Damn, I was wondering about the same. Could you please explain more

[@mecosecos]

How does Bernoulli's principle not apply here?

[@caleb_helm]

I think that's how carburetors work. The engine pulls in air by the vacuum created from the piston on the intake stroke, and then the flow of air causes the fuel to come up to be mixed with the air (like your spray gun example). :)

[@gerardkiers5794]

The fact that you explain how ik works makes it even more fun to watch!!!!!!!!!!!!

[@grieske]

The explanation of what happens is accurate. This name of the effect is, however, turbulent mixing, not the Venturi effect. The Venturi effect is the decrease in pressure at a restriction according to Bernoulli's law. This can also be used to create a low pressure, but it does not require turbulence nor viscosity. Thanks for the demonstration.

[@SugarFreeEngineering]

Excellent work; I'm going to use a clip of the first example with the paper tube for part of a presentation as an example of the venturi effect and how it relates to my research. Thank you!

[@Traqr]

IIRC the Bernoulli equation relates the speed of a fluid to it's drop in pressure, assuming density and temperature are unchanged. The Venturi effect is when you constrict a fluid stream, causing the fluid speed to increase so the pressure drops. A jet of air is using entrainment to transfer momentum to the ambient air mass, and may be higher or lower pressure than ambient depending on the nozzle orifice. Basically, this video is showing a whole bunch of physical effects!

[@steveyknoxville]

Fantastically clear and precise explanation. Thanks Matthias

[@SeraphimKnight]

That hose-in-the-bucket thing blew my mind! Really cool effect.

[@weaver2109]

If you lower the pressure on that makeshift sprayer, you could probably sustain the flame without using the torch (though it would still have to be high enough pressure to make the fluid flow through the straw, so I'm not sure if that would work.)

[@lezenfilms]

0:10 *Cocaine Snorting 101*

[@zakkyummms]

That comment was so very insightful. Please, I hope you continue.

[@lezenfilms]

zakkyummms No need to be sarcastic, but then again you didn't say much either, I was making fun, and if you don't like it don't click that reply button.

[@CurtyCruise]

Thats joke

[@aomimezura11]

Watch "the most important meal of the day" by the minor prophets

[@Simon-oy7kf]

r/woooosh@@zakkyummms

[@TheClobbersaurus]

Thanks for the fantastic quick explanations and demonstrations. I wish more more informative videos on youtube were of this quality

[@dumanator1]

You refreshed a memory of a modified Preval sprayer someone showed me how to make in my 1st yrs. of work. Same premise as the airhose mod., just attach tube to a screw on replaceable glass lidded container. When your broke, they work awesome. You gave me some good ideas for paint sprayers though, with your excellent drawings. I have to see stuff happen or you might as well talk Wookie? Thanks.

[@matthiaswandel]

"don't try this at home" has no impact on people trying it, and even if you try it and hurt yourself, it's your problem, not mine, regardless.

[@DrDAC-go7hs]

Thanks for the great explanation. 10 years in the making

[@markcalabretta5457]

In the sawdust (injection) pump, the compressed air pushes air out of the top section of the cylinder thereby reducing the pressure in the lower section, as you describe. It operates on the principle of induced current, not the Venturi effect (there is no Venturi tube). Likewise for the hose in the bucket. The flame thrower is an atomizer nozzle. While some atomizers use a Venturi tube, this one doesn't and relies solely on the Bernoulli effect.

[@matthiaswandel]

By your reasoning, the direction that I blow the air wouldn't matter Bernoulli's principle is about conservation of energy in one flow, whereas this is about mixing of streams of fluid. Try thinking a bit more and parroting a bit less.

[@aliasronin5661]

The Venturi effect is shown here. You have to have a high moving air stream for the Venturi effect to even take place hence the air compressor. Take the paper towel roll in the first part of video as the restriction or the narrow part in a closed tube system and the surrounding air around it as the larger tube that you described. The same principle is applied here.

[@williematney713]

What you would have to do is downsize the size of the suction hose going to the insulation to create more vacuum force. You could make a venturi out of PVC pipe, and try the air from reversing a large vacuum, but I think you would most likely need compressed air to do it correctly.

[@pheenix42]

Sir, that last bit was also a perfect demonstration of how an 'afterburner' in a jet engine works...spray fuel into the hot gas stream, and *WOOSH*!

[@lasserpientes77]

I found no better explanation than this example, thanks. I'm from Colombia!

[@zanick2]

it doesnt create a negative pressure, it creates a low pressure zone in the fast moving air.. the ambient pressure in the straw is what pushes out to meet the lower pressure zone

[@matthiaswandel]

sorry, couldn't be bothered to make a version for pedantic types.

[@zanick2]

just trying to help you keep it real. you created a lower pressure zone. vacuum does nothing, pressure does the work. dont you remember this from school?? in physics its good to get the terminology correct.

[@ImBarryScottCSS]

It's not pedantry to say your video is factually inaccurate. It might not seem important once you understand the principle but for kids or beginners coming into fluid dynamics the wrong terminology can really set them back in understanding the basics. They need to realise that it isn't 'negative' pressure, it is merely a lower pressure than the surrounding fluid.

[@videodistro]

Pedantic? No. Accurate, yes.

[@luckygeo1650]

zanick2 ]

[@Sohave]

That is also how a steam injector works for getting water pumped into a pressurized boiler (eg on a powerplant or a steam locomotive) and how a Giesl ejector creates a draft in the boiler of a steam locomotive. Airbrushes and many paint guns uses this to propel the paint.

[@GalacticSparrow]

The missing key is a narrowing tube. Without that it is not utilizing the Venturi Effect. However, I can see how one could consider the outside as an infinitely large tube. In any case, the Venturi tube is specialized application of Bernoulli's principle.

[@mightyfinejonboy]

hi, what a great video !! very interesting effect that a few people in the diy gas turbine forums are looking at, to use as a argumentation for there gas turbine engines. either running dry or using a afterburner.i was talking to someone in regards for using this to help the thrust on there jet powered gokarts .i really liked the way you explained it, and made it very clear. regards jon

[@robertfrench80]

Scott, This is better known as Bernoulli's principle which your teacher might recognize. It's the principle that makes aircraft fly (heavier than air craft anyway) cauburetors work, and atomizers such as the "Flame Thrower" that Mr. Wandel demonstrated very well. Also deep water wells with a surface pump use the same principle. N

[@winnshak]

Great job explaining in such a simplistic format!

[@Observ45er]

But wrong.

[@matteomatwallace]

Since your spray gun hose (straw) is placed in front of the compressed air nozzle, I would argue that the drop in pressure is caused by the Bernoulli Effect - fluids in an area moving faster than the the surrounding area possess less pressure. Since the air moving across the top of the straw is moving so quickly, the pressure drops and causes suction through the straw. Granted, I was a music major and my knowledge of the Bernoulli Effect is limited to its effect on vocal folds! Also granted, I had never heard of the Venturi Effect until just now. Thanks for learning me so good!

[@matthiaswandel]

Matt Wallace Well, since all the air around me isn't moving either, I should then experience a tremendous vacuum from all the air that is not moving, according to your explanation.

[@prowler1992]

Matthias Wandel Matt Wallace The Venturi effect is a subset/example of the Bernoulli Principal. Either can be explained by particle replacement or the pressure/speed-of-flow relationship. Matthias, going off of Matt's explanation, we do experience pressure (not vacumm) from the air that is not moving ~1 atm of pressure. That applied pressure is actually quite important for biological functions! Some people can actually feel pressure differences caused by storm systems because the pressure inside their body is not equalized properly and then the pressure differential is then felt as a force on their joints, for example.

[@Wren6991]

Matthias Wandel Bernoulli's equation is a relation between speed and pressure along a single streamline, that is, a path taken by particles through the fluid. It's not valid in this case because Andrew is trying to compare different streamlines, and because the flow is unsteady. (In fact, the pressure in the jet is more or less atmospheric!) The suction is (as you stated) due to the deceleration of the jet due to turbulence, which causes a rising pressure gradient. Since the air at the far end of the tube is atmospheric, the air at the jet end is must be below atmospheric pressure, hence suction. Your friendly neighbourhood engineering student

[@CoolRiffz]

+Matt Wallace Bernoulli: Fluid pressure is inverse to velocity. Venturi: Fluid pressure in a pipe reduces in a constriction. Since we are talking in very oversimplified terms (compared to actually modeling this with CFD and being realistic about what is happening here), the process would be: #1. The ID of the pipe is expanded when it exits the nozzle into the paper towel roll - most directly relevant to the Venturi principle which relates fluid pressure to pipe ID. #2. The high velocity fluid pushes out the air inside the paper towel roll, and this high velocity compared to the static atmospheric air creates a pocket of low pressure (Bernoulli- ish), which creates a pressure differential that moves air up to fill behind it. That relationship is also the result of the conservation of mass (mass flux in needs to equal mass flux out, the high velocity air going out x the cross sectional area needs to be equal to the velocity of the air entering x the same cross section). It is probably best to phrase this system in the context of the conservation of mass because applying Bernoullis has a lot of requirements, which they would not discuss in music. For example, Bernoullis only applies to inviscid flow, but all fluid is viscous so it will have viscous forces along the inner walls of the paper towel (in the boundary layer). So Bernoullis could only apply outside the boundary layer, and in a pipe this small the boundary layer is significant. Source: Fluid mechanics is a subset of mech engr, I have BSME, MSME

[@fitty77]

+CoolRiffz Not sure if i understand (english is not my native language...), but Bernoulli principle can be related with limitations in flow, derived from pressure drop (that comes from viscous limitations) and pressure gains (inputs, pumps, for example). So you can apply in every system, taking in account the real limitations on a system.

[@saiganeshnangunoori8018]

Crystal clear explanation 😃. It cleared all of my doubts.

[@bigchris4168]

Kind of new to your channel but love your work...Keep doing what your doing man!

[@einsteiner900]

FYI, this application of the Venturi effect is known as an injector, there is a neat Wikipedia article on such devices. They used to be used to pump water into the boilers of steam locomotives using high pressure steam from the boiler.

[@jamest.5001]

When you thought you knew how things work! I love looking at things with great detail, you often learn it's much more interesting than you thought!

[@Observ45er]

But the explanation is incorrect. It is NOT the "venturi effect", but *entrainment* .

[@jimmywaller9376]

Dude you are so smart I don't even know how you have made it this far... WOW. You are amazing!

[@CombraStudios]

Sir Wandel this is my correction, Venturi effect describes drop of static pressure in fluid entering a narrower tube from a wider tube, Coanda effect describes a drop of pressure in ambient fluid around a jet of fast moving fluid I'm a big fan

[@NikLyons]

I love this guy! So many great tutorials! Spreading the knowledge! Thanks!

[@homemadejobee]

I love how you are mixing things up. I love the vids

[@nsideoutn8439]

Great video. Thanks. I saw a comment mentioning all your videos are very informative and good like this so I will be checking out more.

[@superdau]

Hmm... from what I remember from school/uni, the Venturi Effect is the drop of pressure in a constricted part of a tube. It can be used to suck fluids, too, but I don't think what you've shown is the same. But hey any excuse to play with a flamethrower is valid!

[@javonf1]

Hello, awesome video. I am trying to calculate the air intake flow rate related to the pressure drop. Should I just calculate the pressure drop inside the blower and then relate the pressure from the vena contracta with the atm pressure to calculate the intake? Thank you

[@dnsmithnc]

I get the venturi effect now. I've heard of it in a number of contexts all my life but, really did not know what it was exactly. What I see happening is that you're creating a relative low pressure zone in the top of the straw which creates a vacuum which draws up the liquid or gas. Very cool.

[@snowsurfr]

This is awesome! Love the thorough explanations. Subbed.

[@RollingEasy]

I'm about to make up a new exhaust system for the car and I wondered if the angle of the very end of the tube, plays much of a part in better moving the exhaust gasses? Ie. a 45 degree angle (or less), coming out on one side with sliced section facing the 'wind' or with it facing away from the 'wind'. Just curious about how each might affect things. 2:10

[@carlosmanuelromero]

Very Cool, I have a question what software have you used to processing your video ?

[@br-bk1lq]

Also, bernoulli's principle. Fast moving air has less pressure than slower moving air, so the air in the straw is pushed out to replace the difference in pressure due to the difference in velocity.

[@ib9rt]

I noticed you using a fountain pen there. On a different geeky subject, what model of pen was it and what ink? That looked like a nice blue.

[@AirshipNorway]

I really liked they way you explained it. Seen so many and was hard to grasp- you put it very easy. With fire -and math too :)

[@saminsiddiquee2059]

I love this guy. Everyone needs a neighbor like that

[@GalacticSparrow]

Ronin, the Venturi effect describes how fluid accelerates when traveling from a larger area to a smaller one via conservation of matter. The Bernoulli effect describes the pressure difference between fluids with different speeds. Therefore, it is the Bernoulli effect that is drawing in the surrounding air, not the Venturi.

[@martyjoseph9507]

A question for you if I may. I'm wondering if you're riding a small carbureted vehicle up a hill that it cannot accelerate on, is it counter productive to hold the throttle wide open versus just open enough that the engine can fully use? I've always wondered if the airflow would draw the correct amount of gasoline naturally or if it's better to have the jet needle slightly blocking the main jet and restricting gasoline so the mixture is not too rich. I'm talking about the point where the throttle is equal to engine output versus wide open where you can definitely hear the vacuum. My understanding of the theory is the fuel will correctly mix with air based on air speed alone regardless of throttle position above current engine demand. Hopefully I'm clear enough. The furnace seems to support my thoughts though it's a bit reversed.

[@matthiaswandel]

carboureator not working right or fuel filter clogged

[@randomsmile9064]

Man I wish I was as smart as Matthias ... I could do fun crazy things like this without either burning myself, or burning the house down... I love watching you fun videos like this

[@Observ45er]

But the explanation is incorrect. It is NOT the "venturi effect", but *entrainment* .

[@tedro7870]

Thanks! It helped me understand how air compressor can suck. It blew my mind.

[@Observ45er]

It is called entrainment. He describes the effect correctly, BUT *It has nothing to do with the venturi.* sigh. *It is ENTRAINMENT*

[@rwhope]

Your neighbors must love you! Great explanation of the Venturi effect. Thank you

[@MrMDavisson]

Matthias: I need to move about 18 inches of blow-in insulation from one part of my attic (approx 400 sqft) to another, and doing it by lifting & carrying would not work (the spaces are separated). Do you think I could aim a hose attached to the outlet side of my shop vac into the side of a larger hose (4"?) then suck the insulation from the "back" end of the 4" hose and blow it out the "front" end in the new location? Or a leaf blower instead of shop vac?

[@IsaiahStJohn]

As Matt Wallace pointed out, you have confounded Bernoulli's principle with the Venturi effect. Bernoulli's principle is that pressure decreases when velocity of a fluid increases. The Venturi effect is a consequence of Bernoulli's principle in the special case of a fluid flowing through a constricted pipe. It states that a fluid that does not compress will lose fluid pressure at the constriction. It results because the fluid must move faster in a narrow pipe than a wide pipe to move an equivalent volume which leads to a lower pressure by Bernoulli's principle. You provided some very neat demonstrations of Bernoulli's principle, and a couple of them may incidentally also involve the Venturi effect, but Matt Wallace is correct, this video should be titled "Bernoulli's Principle."

[@Woodman721]

What was the flammable liquid you sprayed? Awesome video. 😄

[@FlightHours]

Thanks for this - studying for a pilot’s license and this helped to (finally) conceptualize this. Got a video for aerodynamic lift / Bernoulli’s Principle?

[@Observ45er]

This looks like a bot reply... The video is bad science.

[@SabreCycles]

This is exactly what I was looking for! Now I won't need to experiment as much. TY

[@Johny40Se7en]

Lovely demonstrations. Cheers. That is a cool effect! 😄😊

[@intocoasters]

This is great! I have a fog effect that is more effective is there is a gap between the nozzle and pipe I use for routing. Thank you for sharing.

[@coriscotupi]

There are airplanes that have pumps with no moving parts called ejector pumps (or eductor pumps, or jet pumps) that operate on the principle shown in the video. Some fuel is diverted from the engine-driven high pressure pump, plumbed all the way to the tank where a small volume is ejected inside the tank through a narrow nozzle at high speed. A larger volume of fuel is drawn out of the tank and taken back to the engine - where it ends up going through the engine pump again. Any given parcel of fuel may actually circulate a few times around this loop before finally being pumped into the engine.

[@wafflethug]

You should do a video on how vortex coolers work. Compressed air in - separated cool air and hot air out. No moving parts.

[@williamcox4764]

Your a really smart and inspiring guy when I graduate from high school in gonna go for a degree in things like this thank you for all your knowledge and your videos are inspireing keep up the great work I hope to be like you someday p.s. your dad must have been very proud of the great work you do and all your accomplishments....take care and make a wooden fidget spinner plzzz i started a business making these things....

[@Da9eI]

This is the same method used in those diesel "cannon" style space heaters, there is no high pressure fuel pump - at least for the cheap ones. Just a small air pump, sucking up fuel from the tank by ventury effect and mixing it with air. Just recently found this out after servicing one...

[@monetweldon8672]

Very interesting concept and neat applications. Thank you for making this video with these interesting explanations.

[@Observ45er]

This is wrong. The Venturi Effect has a varying cross section pipe. You have none. This is a false explanation. If you're going to explain something P L E A S E understand it well FIRST This is a fundamental fluid dynamics phenomenon caused by viscosity and called ENTRAINMENT NOT venturi. . ... As pointed out 5 years ago by donepearce and 3 years ago by me,​ this is predominantly entrainment (viscosity causing inter-layer 'friction'). When you Say turbulent mixing, you are the closest to the real science. .. The powder is "sucked" into the tube by the atmospheric pressure accelerating the air into the lower pressure in the tube. That lower pressure is caused by the entrained air moving out lowering the pressure upstream from the high speed nozzle. It is precisely the same thing used in ejector pumps. sigh...

[@monetweldon8672]

@@Observ45er ...ok. My comment still stands, the video is neat. But go off I guess.

[@ABLACKX]

I've always wondered and asked me doctors how the suction cup in the plc training lab worked when there is only compressed air inlet ? don't know why i haven't googled this . Thanx alot man

[@Larenzoid]

A very good explanation, Matt. Thanks for sharing it. I'd heard of the Venturi effect and had a basic idea of it but your demonstrations really make it clear. Be careful with that flame thrower, though. ;-) Larry

[@Beamentch]

Thank you Matthias for such a simple presentation of a complex scientific phenomena. Do you know if the Dyson bladeless fan, which is using the Venturi effect, is more efficient by thrust to power?

[@matthiaswandel]

actually, the venturi effect is very inefficient. And the bladeless fan has a blower inside, which * surprise* has blades!

[@remige2006]

A real venturi action is helped a lot by a narrowing passage.. like all the carburators have. The tube narrows and when it enlarges again there is a drop of air pressure and an increase of air speed.. The Homelite Shop Service Manual says: "Carburator design is based on the venturi principle which is that a gas or a liquid flowing through a neckde-down section ( venturi) in a passage undergoes an increased in speed and a decrease in pressure as compared to its speed and pressure in the full section of the passage. "

[@themightywartit]

Thank you thank you thank you. I always enjoy your lessons they are very well explained

[@catalin23456]

I like your demonstration and your old style pen

[@chocoboy02]

The Video recorder auto-adjusts for the brightness of the flame to prevent the recording from becoming damaged.

[@RonRonnard]

Excellent demonstrations and very clear explanations.

[@BryanCoombes]

It doesn't surprise me you like that Lamy Safari. Love your videos!

[@matthiaswandel]

It's a Pelikan pen, not a lamy