easiest proof

Do you have any thoughts of your own, or are you just capable of parroting crap other people have said?

What f_ _ _ _ _ _ original thoughts have you wrote here, you _ _ _ _ _ _ _ disingenuous m _ _ _ _ _ _ a _ _ _ _ _ _ _?

All iron exhibits magnetism, especially when spinning.

Go ahead, explain your own pure bullshit as to how or why these iron balls would overcome the force of Earth's gravity and attract toward each other ... "The experiment measured the faint gravitational attraction between the small balls and the larger ones..." and yet cannot hold water to their surfaces in a proportional amount, via gravity...

totallackey, the balls in the Cavendish experiment were lead.

The forces in the Cavendish experiment were assumed to be proportional in the sense required by Newton's law of gravitation. A check if the validity of the assumption can only be made by asking whether the resulting average density of the Earth (about 5 times that of water) Cavendish calculated is reasonable or accurate.

Scaling things down in the appropriate way has to be done with care. Suppose a material has an ultimate tensile strength S and a density rho. Now suppose we want to hang a bar of it with square cross-section and length so that the ratio of its dimensions are 1:1:100. Then if we let x be the side of the square the tensile stress at the top of the hanging bar is rho*10x*g (with g being the gravitational field), so the bar will snap under its own weight at x=S/(rho*10*g).

In fact, checking the math more carefully, we can see that it snaps at a vertical length of S/(rho*g) regardless of the cross section, so a scale model just isn't going to have the same behavior.

In principle you can make it scale better by adjusting factors like the gravitational field or the ultimate tensile strength of the material, but those things do not easily scale, and you need to think carefully about how to scale them appropriately.

Also, sometimes figures like the Planck length appear in a formula, an those cases the phenomena just doesn't scale along the corresponding dimension.

totallackey, the balls in the Cavendish experiment were lead.

The forces in the Cavendish experiment were assumed to be proportional in the sense required by Newton's law of gravitation. A check if the validity of the assumption can only be made by asking whether the resulting average density of the Earth (about 5 times that of water) Cavendish calculated is reasonable or accurate.

Scaling things down in the appropriate way has to be done with care. Suppose a material has an ultimate tensile strength S and a density rho. Now suppose we want to hang a bar of it with square cross-section and length so that the ratio of its dimensions are 1:1:100. Then if we let x be the side of the square the tensile stress at the top of the hanging bar is rho*10x*g (with g being the gravitational field), so the bar will snap under its own weight at x=S/(rho*10*g).

In fact, checking the math more carefully, we can see that it snaps at a vertical length of S/(rho*g) regardless of the cross section, so a scale model just isn't going to have the same behavior.

In principle you can make it scale better by adjusting factors like the gravitational field or the ultimate tensile strength of the material, but those things do not easily scale, and you need to think carefully about how to scale them appropriately.

Also, sometimes figures like the Planck length appear in a formula, an those cases the phenomena just doesn't scale along the corresponding dimension.

Thank you for correcting my error concerning the material of construction.

I appreciate it.

My primary point of contention still remains.

The Cavendish Experiment measured the attraction of the larger balls to the smaller balls.

If the larger balls were able to overcome the strength of gravitational attraction of the Earth relative to the smaller balls, then by default the larger balls and the smaller balls would overcome that same force and be able to attract water to their surfaces.

The larger balls did not overcome the strength of the gravitational attraction of the Earth. The net force on the smaller balls continued to be almost straight down, the gravitational effect of the larger balls caused the net force on the smaller balls to perturbed sideways by such a tiny amount that incredibly sensitive equipment was needed to measure it.

The larger balls did not overcome the strength of the gravitational attraction of the Earth. The net force on the smaller balls continued to be almost straight down, the gravitational effect of the larger balls caused the net force on the smaller balls to perturbed sideways by such a tiny amount that incredibly sensitive equipment was needed to measure it.

Did the larger balls exert gravitational force on the smaller balls to an extent it could measured?

Yes or no?

Quote from: itsatorus on March 05, 2017, 10:30:56 AM

The larger balls did not overcome the strength of the gravitational attraction of the Earth. The net force on the smaller balls continued to be almost straight down, the gravitational effect of the larger balls caused the net force on the smaller balls to perturbed sideways by such a tiny amount that incredibly sensitive equipment was needed to measure it.

Did the larger balls exert gravitational force on the smaller balls to an extent it could measured?

Yes or no?

Yes.

Quote from: totallackey on March 05, 2017, 10:38:21 AM

Quote from: itsatorus on March 05, 2017, 10:30:56 AM

The larger balls did not overcome the strength of the gravitational attraction of the Earth. The net force on the smaller balls continued to be almost straight down, the gravitational effect of the larger balls caused the net force on the smaller balls to perturbed sideways by such a tiny amount that incredibly sensitive equipment was needed to measure it.

Did the larger balls exert gravitational force on the smaller balls to an extent it could measured?

Yes or no?

Yes.

Okay.

Then the gravity of the larger balls would also be able to attract and hold water right in front of my eyes.

Quote from: itsatorus on March 05, 2017, 10:40:02 AM

Quote from: totallackey on March 05, 2017, 10:38:21 AM

Quote from: itsatorus on March 05, 2017, 10:30:56 AM

The larger balls did not overcome the strength of the gravitational attraction of the Earth. The net force on the smaller balls continued to be almost straight down, the gravitational effect of the larger balls caused the net force on the smaller balls to perturbed sideways by such a tiny amount that incredibly sensitive equipment was needed to measure it.

Did the larger balls exert gravitational force on the smaller balls to an extent it could measured?

Yes or no?

Yes.

Okay.

Then the gravity of the larger balls would also be able to attract and hold water right in front of my eyes.

In principle, you could replace the small balls with buckets of water and see the attraction in the form of the rotation of the torsion bar, but the larger balls would not "hold" water to their surface, if what you mean by that is that the force at their surface would exceed the gravitational force of Earth so that water would fall up when directly underneath the ball.

If the large balls were point masses, it would be possible to calculate the distance at which their gravitational fields exceeded the local field of the earth, but that distance is much shorter than their actual radii.

Quote from: itsatorus on March 05, 2017, 10:40:02 AM

Quote from: totallackey on March 05, 2017, 10:38:21 AM

Quote from: itsatorus on March 05, 2017, 10:30:56 AM

The larger balls did not overcome the strength of the gravitational attraction of the Earth. The net force on the smaller balls continued to be almost straight down, the gravitational effect of the larger balls caused the net force on the smaller balls to perturbed sideways by such a tiny amount that incredibly sensitive equipment was needed to measure it.

Did the larger balls exert gravitational force on the smaller balls to an extent it could measured?

Yes or no?

Yes.

Okay.

Then the gravity of the larger balls would also be able to attract and hold water right in front of my eyes.

Why does being able to be measured mean it should attract water enough as to overcome the Earth's gravitational pull on the water? 
He said a very tiny attraction measured be very sensative equipment.  Do you think your eyes are very sensative devices capable of measuring amounts that tiny?

Also do you know why he used lead instead of iron?  It is of some importance.  I already do know why, I am asking totallackey though.

Now, the Cavendish experiment has been widely criticized by the scientific community because never in over two centuries since its creation has anyone been able to replicate it!

https://arxiv.org/pdf/1505.01774.pdf

The Cavendish experiment has been replicated many, many times. There are also a number of other experimental techniques (atom interferometry , using satellite data, etc.) that have been used to estimate the value of big G. The paper linked above contains a summary of over 20 big G measurements since 1980, including a nice little summary paragraph for about 10 of the experiments.

**Realize this was already addressed, but I wanted to post this paper in particular since it is a nice summary paper on the most accurate big G measurements since 1980. It also contains all the information you would need to track down the papers/research groups for each of the experiments.

What f_ _ _ _ _ _ original thoughts have you wrote here, you _ _ _ _ _ _ _ disingenuous m _ _ _ _ _ _ a _ _ _ _ _ _ _?

I have plenty. Where have I just copied and pasted crap or parroted crap like you have?

All iron exhibits magnetism, especially when spinning.

Are you sure about that? Or is that just another one of your parroted nonsense claims?
Are you sure you aren't thinking of spinning molten iron? The molten part is really important.

Anyway, that is irrelevant. The balls weren't iron, they were lead.

Go ahead, explain your own pure bullshit as to how or why these iron balls would overcome the force of Earth's gravity and attract toward each other ... "The experiment measured the faint gravitational attraction between the small balls and the larger ones..." and yet cannot hold water to their surfaces in a proportional amount, via gravity...

Again, you aren't listening.
They aren't overcoming Earth's gravity to hold the balls to one another.
At the surface of the balls, the gravitational attraction of Earth is still far stronger than the gravitational attraction of the balls. But they are in different directions.
This means the balls can move towards one another.

No one who honestly and rationally analyses the experiment will think they should be able to hold water because they can attract each other.

Then the gravity of the larger balls would also be able to attract and hold water right in front of my eyes.

Not in the presence of the gravitational field of Earth.

You are spouting pure bullshit.

Just because they experience a sideways force from each other doesn't mean they will be able to hold water to their surface.
Yes, they could attract water to their surface, similar to how the moon does with the tides, but that attraction would not be visible with the naked eye.

Like I said, if you want to claim such childish bullshit then do the math to prove it.

In principle, you could replace the small balls with buckets of water and see the attraction in the form of the rotation of the torsion bar, but the larger balls would not "hold" water to their surface, if what you mean by that is that the force at their surface would exceed the gravitational force of Earth so that water would fall up when directly underneath the ball.

If the large balls were point masses, it would be possible to calculate the distance at which their gravitational fields exceeded the local field of the earth, but that distance is much shorter than their actual radii.

In principle, the water would be falling to the center of the larger and balls, not down to earth.

Quote from: itsatorus on March 05, 2017, 11:07:27 AM

In principle, you could replace the small balls with buckets of water and see the attraction in the form of the rotation of the torsion bar, but the larger balls would not "hold" water to their surface, if what you mean by that is that the force at their surface would exceed the gravitational force of Earth so that water would fall up when directly underneath the ball.

If the large balls were point masses, it would be possible to calculate the distance at which their gravitational fields exceeded the local field of the earth, but that distance is much shorter than their actual radii.

In principle, the water would be falling to the center of the larger and balls, not down to earth.

Why?  What makes them cancel the gravitational field of the Earth while on the surface of the Earth?

Why does being able to be measured mean it should attract water enough as to overcome the Earth's gravitational pull on the water? 
He said a very tiny attraction measured be very sensative equipment.  Do you think your eyes are very sensative devices capable of measuring amounts that tiny?

Also do you know why he used lead instead of iron?  It is of some importance.  I already do know why, I am asking totallackey though.

Cavendish used his eyes.

Why?  What makes them cancel the gravitational field of the Earth while on the surface of the Earth?

What makes the Moon overcome the gravitational field of the Earth from a supposed quarter million miles away?

Quote from: itsatorus on March 05, 2017, 10:30:56 AM

The larger balls did not overcome the strength of the gravitational attraction of the Earth. The net force on the smaller balls continued to be almost straight down, the gravitational effect of the larger balls caused the net force on the smaller balls to perturbed sideways by such a tiny amount that incredibly sensitive equipment was needed to measure it.

Did the larger balls exert gravitational force on the smaller balls to an extent it could measured?

Yes or no?

There is this article with an explanation of the effect gravitation with a very simple set-up to demonstrate it: Bending Spacetime in the Basement.
There are four related videos, all are referenced in the arcticle:
" class="bbc_link" target="_blank" rel="noopener noreferrer">Bending Spacetime in the Basement: Video 2, John Walker
" class="bbc_link" target="_blank" rel="noopener noreferrer">Bending Spacetime in the Basement: Video 3, John Walker
" class="bbc_link" target="_blank" rel="noopener noreferrer">Bending Spacetime in the Basement: Video 4, John Walker

It is purely a demonstration. not attempt to measure G.

In principle, the water would be falling to the center of the larger and balls, not down to earth.

No.
In principle, the water would be falling in the much larger gravitational potential of Earth, down to Earth.

Like I said, do the math.

Quote from: Mikey T. on March 05, 2017, 12:25:35 PM

Why?  What makes them cancel the gravitational field of the Earth while on the surface of the Earth?

What makes the Moon overcome the gravitational field of the Earth from a supposed quarter million miles away?

It doesn't.
How often do you see water fly up towards the moon?
NEVER.
It stays on Earth.
Yes, it bulges slightly.
This is due to the approximately 6400 km difference between the centre and the point closest to the moon, as well as the moons much larger mass.

You wish to keep the gravitational acceleration of Earth the same, but have something with a gravitational attraction much much much much much much smaller than that of the moon, and still expect a similar effect with even greater magnitude.
That is just irrational garbage.
No one in their right mind would expect that.

Can you do the math to show what the gravitational attraction between water and the lead balls would be?

Quote from: itsatorus on March 05, 2017, 11:07:27 AM

In principle, you could replace the small balls with buckets of water and see the attraction in the form of the rotation of the torsion bar, but the larger balls would not "hold" water to their surface, if what you mean by that is that the force at their surface would exceed the gravitational force of Earth so that water would fall up when directly underneath the ball.

If the large balls were point masses, it would be possible to calculate the distance at which their gravitational fields exceeded the local field of the earth, but that distance is much shorter than their actual radii.

In principle, the water would be falling to the center of the larger and balls, not down to earth.

Only if the gravitational field of the lead ball was stronger than the gravitational field of the Earth, which it wasn't.

Here are some numbers to help you:
The large spheres had a radius of 0.15 m and a mass of 158 kg.
The small spheres had a radius of 0.0255 m and a mass of 0.73 kg.
Earth has a radius of ~6 371 000 m and a mass of roughly 5 972 370 000 000 000 000 000 000 kg.

The distance between (centre to centre) the balls was 0.225 m.

The formula used to determine the force between 2 objects due to gravity is:
F=GmM/r^2,
where F is the force, G is the universal gravitational constant, with a value of 6.67408 * 10^-11 m^3/(kg s^2),
m is the mass of one object (typically taken to be the smaller one),
M is the mass of the other object (typically taken to be the larger one), and
r is the distance between the objects (centre to centre).

You can also use the formula for gravitational acceleration of any generic mass by noting that F=ma, and thus a=F/m.
Thus the acceleration due to gravity of a small mass (m) to a larger, mass (M) is:
a=GM/r^2.

So can you use that to determine the force between the balls, and the acceleration of the water to the balls or to Earth?


Also, yes, he used his eyes, but not only his eyes. He used a vernier scale, something made to measure things too small to easily be measured by the human eye.

You can also do other things, like find the hypothetical non-rotating L1 point between the large ball and Earth.
You find this by using the gravitational acceleration formula for Earth and the large ball, and letting the distance vary, taking note that the total distance must be the distance between the ball and Earth.
However, due to Earth's much larger size, we can simplify and just use g for that.
Thus the L1 point (the point were the water would remain stationary between the ball and the Earth rather than falling to either) can be found as:
g=GM/r^2
r^2=GM/g
r=sqrt(GM/g)
=sqrt( (6.67408 * 10^-11 m^3/(kg s^2)) * 158 kg / (9.8 m/s^2))
=sqrt(1.076 * 10^-9 m^2)
=3.28 * 10^-5 m = 32.8 um.

So if the large balls were less than 32.8 um (yet still weighed the same), then water might stand a chance at sticking to its surface.
However, I think at that scale, tidal forces will still screw you over, so you still need to put it outside Earth's Roche limit.

Of course, surface tension would stick it there much sooner.

So no, on principle, the water should fall to Earth.

Only if the gravitational field of the lead ball was stronger than the gravitational field of the Earth, which it wasn't.

So the gravitational field of the lead ball is strong enough to exert influence on a smaller lead ball in excess of that of the Earth, but not strong enough to exert influence enough on a lighter element such as water...

Very interesting...

Not.

Quote from: itsatorus on March 05, 2017, 12:54:59 PM

Only if the gravitational field of the lead ball was stronger than the gravitational field of the Earth, which it wasn't.

So the gravitational field of the lead ball is strong enough to exert influence on a smaller lead ball in excess of that of the Earth, but not strong enough to exert influence enough on a lighter element such as water...

Very interesting...

Not.

No. It isn't in excess of that of the Earth, it is in a different direction to that of Earth which means it can be measured.

It is strong enough to do the same for water, and if you had a stream of water next to it you may be able to notice a very slight deflection of the stream, but I doubt it as you wont be able to use a vernier scale to measure it.

Regardless, as has been said many times, it isn't holding that lead ball up against gravity. It is moving it sideways slightly.

Quote from: itsatorus on March 05, 2017, 12:54:59 PM

Only if the gravitational field of the lead ball was stronger than the gravitational field of the Earth, which it wasn't.

So the gravitational field of the lead ball is strong enough to exert influence on a smaller lead ball in excess of that of the Earth, but not strong enough to exert influence enough on a lighter element such as water...

Very interesting...

Not.

No, the force exerted by the gravity of the large ball was much less than the force exerted on the small ball by the Earth's gravity.

No. It isn't in excess of that of the Earth, it is in a different direction to that of Earth which means it can be measured.

If all objects are falling to the center of the Earth because of gravity and the gravity of a lead ball is strong enough to alter the fall of a smaller ball to the center enough to be measured, then yes, I would call that excess.

Quote from: JackBlack on March 05, 2017, 01:17:58 PM

No. It isn't in excess of that of the Earth, it is in a different direction to that of Earth which means it can be measured.

If all objects are falling to the center of the Earth because of gravity and the gravity of a lead ball is strong enough to alter the fall of a smaller ball to the center enough to be measured, then yes, I would call that excess.

No. The large ball didn't alter the fall.
The rod it was suspended from did.
Don't worry, that rod is also quite capable of holding up water, just like it is capable of holding up the balls.

All the large ball did was tilt the ball slightly.

Quote from: JackBlack on March 05, 2017, 01:17:58 PM

No. It isn't in excess of that of the Earth, it is in a different direction to that of Earth which means it can be measured.

If all objects are falling to the center of the Earth because of gravity and the gravity of a lead ball is strong enough to alter the fall of a smaller ball to the center enough to be measured, then yes, I would call that excess.

Are you under the impression that the net force on an object is the maximum of the component forces, instead of the ordinary vector sum? So if, for example, you put two rockets at a 90 degree angle on a dolly designed to move freely in any direction, you think the dolly would move straight along the path of the stronger rocket, and not at an angle between them that depends on the relative sizes of their forces? Because otherwise it's hard to understand your argument.

Quote from: JackBlack on March 05, 2017, 01:17:58 PM

No. It isn't in excess of that of the Earth, it is in a different direction to that of Earth which means it can be measured.

If all objects are falling to the center of the Earth because of gravity and the gravity of a lead ball is strong enough to alter the fall of a smaller ball to the center enough to be measured, then yes, I would call that excess.

No, all objects do not fall "to the center of the Earth because of gravity",
they are attracted "to the center of the Earth because of gravity".

The small ball experiences its own weight pulling it down and a very slight force attracting it to the large ball.

Gravitation is precisely additive so the nett force on any object due to gravitation is the sum of those due to all objects. Most objects are too small and too far away to have a significant effect.

In the Cavendish type experiment, all relevant objects are fixed in place expect for the large and small balls.
Hence moving the large balls produces a very small nett force on the small balls towards the large ones.

You will note that in Cavendish's case, he observed the experiment from a distance through a telescope.
Failure to observe the correct precautions will lead to meaningless and very variable results,
but you will note that the results from that first set of experiments were within 1% of the current value.

Here are the results of the first four sets of experiments and the currently accepted value (as of 2004):
Experimenter        Date    Result   Deviation %
Cavendish H.         1798       6.74         0.986
Reich F.                   1838       6.63        -0.662
Baily F.                    1843       6.62        -0.812
Cornu A, Baille J.  1873       6.63        -0.662
PRESENT VALUE   2004       6.6742   ±0.0150

All within 1% of the current value

No. The large ball didn't alter the fall.
The rod it was suspended from did.
Don't worry, that rod is also quite capable of holding up water, just like it is capable of holding up the balls.

All the large ball did was tilt the ball slightly.

Quote from: totallackey on March 05, 2017, 10:38:21 AM

Did the larger balls exert gravitational force on the smaller balls to an extent it could measured?

Yes or no?

Yes.

Now its the rod and not the ball...

You guys cannot make up your own minds.

Quote from: JackBlack on March 05, 2017, 01:48:40 PM

No. The large ball didn't alter the fall.
The rod it was suspended from did.
Don't worry, that rod is also quite capable of holding up water, just like it is capable of holding up the balls.

All the large ball did was tilt the ball slightly.

Quote from: itsatorus on March 05, 2017, 10:40:02 AM

Quote from: totallackey on March 05, 2017, 10:38:21 AM

Did the larger balls exert gravitational force on the smaller balls to an extent it could measured?

Yes or no?

Yes.

Now its the rod and not the ball...

You guys cannot make up your own minds.

The large ball created a small sideways gravitational force on the small ball. If the ball had been in freefall, it would have fallen almost straight down with a very slight sideways motion resulting from the gravity of the large ball.

The reason the ball didn't fall down is because it was hanging from a rod, in a way not entirely dissimilar to how the toys on a child's mobile don't fall because they are hanging. A very gentle gust of wind could cause the mobile to turn, but it would be odd to say that this gust of wind "exceeded" the force of Earth's gravity.

Quote from: JackBlack on March 05, 2017, 01:48:40 PM

No. The large ball didn't alter the fall.
The rod it was suspended from did.
Don't worry, that rod is also quite capable of holding up water, just like it is capable of holding up the balls.

All the large ball did was tilt the ball slightly.

Quote from: itsatorus on March 05, 2017, 10:40:02 AM

Quote from: totallackey on March 05, 2017, 10:38:21 AM

Did the larger balls exert gravitational force on the smaller balls to an extent it could measured?

Yes or no?

Yes.

Now its the rod and not the ball...

You guys cannot make up your own minds.

No. It is still the ball.
The rod stopped the balls from falling to the ground.
The rod was what supported the weight of the ball.
But the rod was free to pivot.
The gravitational attraction between the balls caused the rod to pivot.
It didn't hold the balls up against Earth's gravity.

We can make up our minds, and we aren't changing anything.
You just seem incapable of having a thought which uses more than 1 thing.