1798 - Henry Cavendish

[Rolf Guthmann]

“In 1798 Henry Cavendish published a paper in Philosophical Transactions reporting the results of an experiment. This entailed measuring the attraction between two objects on an apparatus called a torsion balance. Cavendish discovered that when he heated one of the objects the attraction between the objects increased. For over two hundred years the physics establishment has either ignored, or tried to explain away, this result.”

I found the text above, but in that book it doesn't have details.
Does anybody of the forum know that experience??
Which is the best explanation for this phenomenon?

I thank the collaboration at once.

Rolf .... http://www.geocities.com/rolfguthmann/

[Tide]

I notice you didn't provide a citation for that quotation nor any substantive details.

[nightcleaner]

Heat is energy. Energy is mass. In theory, heating an object will increase its mass, so will increase the attraction. But the amount of increase is way too small to be measured by crude apparatus. This post doesn't pass the smell test. Surely, Rolf, you can make it sweeter?

Thanks,

nc

[p53ud0 dr34m5]

Cavendish discovered that "the arm moved backwards, in the same manner that it before move forward". Gravity is not supposed to involve repulsion. The second result was that after heating one of the weights "the effect was so much increased, that the arm was drawn 14 division aside, instead of about three". Heating one of the weights increased the attraction. I had no problem with this. The heating increased the emission of the weight and when this was absorbed by the other weight it increased the attraction. This is also against the physics law of gravity. Despite the fact that the Cavendish Experiment is seen as a great physics experiment the results are ignored. So what about this gravitational constant that Cavendish demonstrated was not constant? It's a measure of electrostatic attraction.

I found that. I don't know if it will be of any use.

Heat is energy. Energy is mass. In theory, heating an object will increase its mass, so will increase the attraction.

Yes, heat is energy. When adding heat it increases the kinetic energy of the molecules that compose that object. With the theory that mass increases with velocity, your explanation could be right. I've read that many physicists choose to ignore the theory of mass increase due to velocity, so I wouldn't find your explanation that valid.

If you guys want a source for the quoted information at the top, just PM me.

[Tide]

If you're referring to Cavendish's gravity experiments isn't it more likely that heating one of the masses would produce thermal convection of the air in the room? He didn't do the experiments in a vacuum. Also, heating in the confined quarters of his experimental chamber would surely have affected the torsional constants.

[p53ud0 dr34m5]

Whom are you questioning?

[Doc Al]

If you guys want a source for the quoted information at the top, just PM me.
Sounds like the rantings of Stephen Mooney. :yuck:

[Doc Al]

Here's an excerpt of an article on gravity from the 1911 edition of Encyclopedia Britannica (found online); it is describing Cavendish's torsion balance experiments:
undoubtedly very accurate for a pioneer experiment and has only really been improved upon within the last generation. Making various corrections of which it is not necessary to give a description, the result obtained (after correcting a mistake first pointed out by F. Baily) is ~ 5.448. In seeking the origin of the disturbed motion of the torsion rod Cavendish made a very important observation. He found that when the masses were left in one position for a time the attracted balls crept now in one direction, now in another, as if the attraction were varying. Ultimately he found that this was due to convection currents in the case containing the torsion rod, currents produced by temperature inequalities. When a large sphere was heated the ball near it tended to approach and when it was cooled the ball tended to recede. Convection currents constitute the chief disturbance and the chief source of error in all attempts to measure small forces in air at ordinary pressure.

(Reference: http://1911encyclopedia.org/G/GR/GRAVITATION.htm)

[p53ud0 dr34m5]

How observant Doc Al! Yea, that was from Stephen Mooney. I do have a question though: Why does the experiment involve repulsion? I was wanting to know if there was a site with his whole paper on his experiment, so I could digest it myself. I find it peculiar for an experiment to find a constant for attraction to yield data that involves repulsion. I want to see this for myself.