Bernoulli's principle

The narrower the pipe section, the lower the pressure in the liquid or gas flowing through this section. This paradoxical fact, following from the law of conservation of energy, is called the Bernoulli principle or law.

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[Cristoforo]

This principle humbled me as a young scientist and student pilot. I thought I knew everything, that I had an intuitive grasp of basic physics. It took me a long time to wrap my head around this one principle.

[jamesstuart]

Same thing happens when high-pressure information passes through my low-pressure brain

[HenrikMyrhaug]

This phenomenon is one of the most mind- fucking results in all physics to me. The fact that blowing air with high pressure through a tube with a restriction causes the air to decrease in pressure at the restricted part is so counterintuitive. My brain just will not understand how increasing the space in which a fluid can flow causes the pressure of the fluid to increase and vice versa.

[alexistarr]

I've just finished reading James Burke's superb book Connections, which I would recommend to anyone interested in the history of scientific ideas. In this book he explains how this principle was used to create carburettors, making possible the internal combustion engine and jet engines, and how the principle it could be used to measure the flow of a gas through a pipe. However, limited space only allowed him to give a brief overview of these things. The excellent demonstrations in your video make it easy to get my head around these concepts.

[marymccluer]

Great demonstrations of Bernoulli's principle! Seeing the effect in action helps to understand it.

[bobmoandfriend]

demonstrating college level fluid dynamic physics with plastic and a cheap blower. I applaud your ability to demonstrate what so many professors rely on overly complicated texts and complex mathematics to explain. BRAVO!

[xdragonk]

The interesting part is that if you close the system, when you blow, pressure increases. However, when you open so that the air can flow, the pressure decrease the faster it goes.

[sudeeptagorai]

Best explanation of Bernoulli's principle I came across on internet. Thank you so much!!

[sandrorodriguez]

One of the clearest explanations of Bernoulli's Principle that I have seen. Everything very well explained, and many examples showing how everything works. Thank you very much!

[johnroberts]

What a superb video lesson. Very clear and engaging. Many thanks.
😊

[fzpspuf]

This video is awesome! It explains teh principle in a simple way, as well as showing *how* it works and demonstration of the use

[strumpeteer]

So... the two balls were "sucked" towards each other because the two balls created a small channel for air or water to pass, thus creating lower pressure compared surrounding space (atmospheric pressure). This lower pressure in this smaller channel creates a vaccum, pulling the balls together.

[walkabout]

In realms of air where wings take flight,
A dance of forces, pure and bright.
Bernoulli whispered secrets old,
In currents swift, a tale unfolds.

Above, below, a magic play,
In skies where dreams find their own way.
A symphony of pressure and speed,
A waltz unseen, the laws decreed.

As air flows, it weaves a song,
A melody where forces throng.
Upon the wings of birds in flight,
Bernoulli's dance, a graceful height.

At curves and bends, in fluid grace,
The air, a partner in this chase.
Velocity and pressure dance,
In every move, a sweet romance.

From wings that lift to planes that soar,
A principle forevermore.
In tubes, in winds, in rivers wide,
Bernoulli's truth, an endless guide.

A theorem sung in skies so blue,
In clouds and dreams, forever true.
A whispered secret, nature's rhyme,
Bernoulli's principle, through space and time.

[Arsenic]

The first demonstration (with the 2 balls) perfectly explains porpoising in Formula 1.

[gog]

The correct term is to say `Bernoulli's' Integral', since it is just an integral of the Euler's equations of motion for a particular case of steady, inviscid and potential flow. The term `principle' is related to something very fundamental, like The Principle of Least Action etc.

[bernardfoot]

Fascinating video. However, I am not sure that the ball hanging in the water coming from a tap is really demonstrating the Bernoulli principle.

Firstly, the water is not being constrained to flow through a narrower channel - it is free to flow over the surface of the ball and so the cross section of the flow is probably not reduced.

Secondly, if you look at the flow of water coming off the bottom of the ball, it is deflected to the right after it has flowed over the surface of the ball. Changing the direction of the water flow to the right causes a reactive force on the ball towards the left, and this is probably what makes the ball appear to cling to the water - the ball comes to a rest where this leftward force is balanced by the rightward force of the downward water flow pushing on the ball.

[gospelrwanda]

The pressure reduction is due to the expanding exit and not the narrow part of the system. The width of the entry may not be important but the exit, the wide exit creates a sudden increased volume hence the reduced pressure. I would like to see the same experiment be done without the expanding exit and see if there will be any differences

[libertyvilleguy]

An excellent learning aide. Very well done.

[selfunderstanding]

Very simplified demonstration of the basic principle of Bernoulli .I wish some body could have explained me in my school level in such a lucid language.

[tareknasr]

You made my echocardiogram studies easier, thank you