# Does the Torricelli Vacuum Experiment Prove the Strength of Vacuum Forces?

• B
• Rotating Wave
In summary: The pressure inside the tube would be higher than the pressure outside, so the speed would be higher than if there was no pressure.
BvU said:
G is not the magnitude of gravity. It is the magnitude of the gravitational force.

##G_k## is the gravitational constant. It is NOT the equivalent of ##a## in ##F = ma##.
The dimension of ##G_k## is length3 x mass-2 x time-2, units Nm2/kg2.
The dimension of 'a' is length x time-2, units m/s2 .

And 'm' is a mass, in kilogram, NOT the product of two masses divide by the square of their distance: the latter has a dimension kg2/m2, which is incomparable.
Ok. I see! Thank you. I guess I have more studying to do.

BvU said:
In a textbook you can find the equivalent you are seeking:

If we use the mass and radius of the earth, we can write $$g = {G_k\, m_{\text earth} \over r_{\text earth}^2}$$ and THEN ##g## is an acceleration and ##mg## is a force.

https://en.wikipedia.org/wiki/Gravitational_constant#Definition

##\ ##
Yeah, I need to study more. It makes sense. I appear to have concepts mixed up. I didn't realize G_k had a different dimensional property though, now I can see how I should have known from reverse engineering the math.
Ok. So it looks like I'll be hitting the basics again to solidify the concepts.

BvU
BvU said:
Actually there is a very low pressure water vapour. So low that it's a vacuum for our perception.
I disagree. A vacuum contains all the laws of the universe. It may be in the form of fields such as the Higgs field. That's a lot more than nothing.

StandardsGuy said:
A vacuum contains all the laws of the universe
Don't forget dreams, hope and charity.

I wholeheartedly disagree, but you are entitled to your opinion. Any experimental evidence ?

BvU said:
Don't forget dreams, hope and charity.

I wholeheartedly disagree, but you are entitled to your opinion. Any experimental evidence ?
I think I get what Standards guy is saying. Space is a vacuum and holds all of the laws of the universe (because it basically IS the universe), so any artificial vacuum - like Torricelli's - would have those same traits, including fields.
In that case, space is the experimental evidence of a vacuum having all the laws of physics.
I think that's what they were saying...

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