[Bored chemist]

If you want a bit more sensitivity it would be relatively simple to use a heavier test mass, but to offset most of its weight with a counterweight. That way the analytical balance only has to handle the difference between two masses.
If you choose to play that game you can also set up the rig so that the two masses are "far" from the balance itself so they won't perturb it.

At least part of the surface of the object has to be a well defined colour so that you can use an IR thermometer to measure the temperature without touching it. Black is the best choice.
Of course, just heating the copper to oxidise it until it's black would also work.

[alancalverd]

Indeed we can offset the mass with a counterweight. I have in mind about a gram each side of the balance.

The problem with paint or an oxide layer is outgassing when the target is heated. But if we shine a light through a small hole into a hollow sphere, we can assume that (A-a)/A of the incident energy is absorbed where A is the area of the sphere and a the area of the hole, so we can calculate the mean temperature rise of the target, which will be less than the surface temperature rise you would measure with an IR thermometer.

Once heated, the mass will remain lighter until it cools, and we can make it lighter still by adding a bit more heat. That will suffice for a qualitative demonstration even if the numbers look a bit rough.

[Bored chemist]

Calculating the temperature rise means knowing the laser power exactly.
That's not a very difficult thing to measure, but I'd rather not have to.
Measuring the temperature of the block directly seems to me like a better approach.
Either would work.
 If you shine the light in at a slight angle and assume the sphere isn't very well polished on the inside then you can assume the whole of the incident light is absorbed- the amount reflected out of the hole will be tiny.

It's just a thought, with a high power laser you could check the accuracy of the balance by using photon pressure as llong as you knew the beam power.
Out-gassing would be a real problem if we were talking about  a high vacuum, but in this case I think that taking say 99.9% of the air out will reduce the effects of convection by a thousandfold. If ( as I strongly suspect) the results for "mass loss" reported earlier are actually due to convection then they should fall by roughly the same fraction as the air pressure.

For a chamber at 1 mBar the out-gassing's going to be irrelevant.

There's a microbalance that doesn't get used much where I work; I wonder if they would "lend" it to me :-)

Checked eBay
https://www.ebay.co.uk/itm/CAHN-INSTRUMENTS-C-30-MICROBALANCE-10930-02F-MICRO-BALANCE/232585605861?hash=item36272eb2e5:g:ORIAAOSwk~ZaJVox

I think those blances have a capacity of over a gram and a best resolution of a microgram

[Yaniv (OP)]

The expenditure of £5 - 10,000 seems very reasonable if the result disproves all that we know about physics.Given the chance of a Nobel prize if he's right, Mr Yaniv should now put his money where his mouth is.  Happy to donate a week of my time at the Cavendish, Engineering or Chemistry labs near here, Leeds, Imperial, or wherever Yaniv can find a bench and some kit.

I am not employed at the University of Leeds and don't have access to a bench or a kit. But I am happy to pay you the above sum to conclude the experiment.

[Kryptid]

Now I'll calculate how much E=mc² predicts mass should increase with temperature. I'll consider a material will well-studied properties: silicon dioxide (silica). Solid silica has an average heat capacity of 1.165 J/g*K (averaged over the temperature range at which it is a solid). If we start at room temperature (273.15 Kelvins) and raise a block of solid silica up to its melting point (1,986 Kelvins), that is a temperature increase of 1,712.85 Kelvins. That represents an energy increase of 1,995.47 J/g in the silica block. In accordance with E=mc², 1 gram of mass is equivalent to 89,875,517,873,681,786 joules of energy (or alternatively, that 1 joule of energy is 1.1126501 x 10^-17 grams).  So that means 1 gram of silica heated from room temperature up to its melting point will gain 2.2202598 x 10^-14 grams of weight. For 1,000 metric tons of silica, that's a gain of 0.000022202598 grams. That's a very, very small amount.

[alancalverd]

Calculating the temperature rise means knowing the laser power exactly.
That's not a very difficult thing to measure, but I'd rather not have to.

No problem.I can borrow a laser power meter. In fact the best ones seem to be , would you believe, a hollow copper sphere with a small hole and a thermistor.

The Cahn balance is a null device, so you can calibrate it with milligram weights, IIRC.

At this stage we aren't too concerned about accuracy anyway. The question is one of orders of magnitude  between Kryptid's calculation from conventional relativity and Yaniv's proposal.

[Bored chemist]

The Cahn balance is a null device, so you can calibrate it with milligram weights, IIRC.

True, but f it's inside a vacuum chamber, that's a fiddly job- and if you happen to have a laser...

No problem.I can borrow a laser power meter.

Getting someone else to do the calibration's always an option, but I still prefer the direct approach.
Different folks...
Both options would work, which puts them one up on the actual experiment which won't work.
(You can I know that a negative result is still a result but I'm not sure it would satisfy this particular audience.)

[Yaniv (OP)]

@alancalverd @Bored chemist Did you do the experiment and do you have results ?

[alancalverd]

The expenditure of £5 - 10,000 seems very reasonable if the result disproves all that we know about physics.Given the chance of a Nobel prize if he's right, Mr Yaniv should now put his money where his mouth is. Happy to donate a week of my time at the Cavendish, Engineering or Chemistry labs near here, Leeds, Imperial, or wherever.

[Yaniv (OP)]

Quote from: alancalverd on 28/01/2018 11:28:45
The expenditure of £5 - 10,000 seems very reasonable if the result disproves all that we know about physics.Given the chance of a Nobel prize if he's right, Mr Yaniv should now put his money where his mouth is. Happy to donate a week of my time at the Cavendish, Engineering or Chemistry labs near here, Leeds, Imperial, or wherever.

I thought you agreed to do the experiment and I will pay you after the results are published on this thread or elsewhere in the scientific literature or on the internet. How do you want me to pay you right now ?

[Yaniv (OP)]

This is another paper measuring weight of heated metals decreases at increasing temperature.
http://www.enginsci.cn/ch/reader/create_pdf.aspx?file_no=20091215001&flag=&journal_id=chinaes

[Bored chemist]

Find me a set of instructions for a decent balance that doesn't explain that you shouldn't weigh hot things, because of convection currents.

[Yaniv (OP)]

Find me a set of instructions for a decent balance that doesn't explain that you shouldn't weigh hot things, because of convection currents.

In this paper metals were heated inside a thermal insulator to reduce convection currents. Weighing the apparatus in vacuum would eliminate heat convection all together. What happened to the laser method of heating ? I thought it was a cool experiment.

[syhprum]

Alan
"50 microgram is a heck of a lot, if converted to energy. 4500 joules"
I feel you have underated the value of c by a factor of 1000 also you have not taken into account the the specific heat of the sample and assumed it to be unity which is unlikely.
This of course shows that the suggestion put forth by Yaniv is even less likely to be true

[Yaniv (OP)]

Alan
"50 microgram is a heck of a lot, if converted to energy. 4500 joules"
I feel you have underated the value of c by a factor of 1000 also you have not taken into account the the specific heat of the sample and assumed it to be unity which is unlikely.
This of course shows that the suggestion put forth by Yaniv is even less likely to be true

What 50 micrograms are you talking about ?

[Yaniv (OP)]

The is another paper measuring weight of a heated thermal insulator decreases at increasing temperature.
http://intellectualarchive.com/getfile.php?file=ueSLj97NCAp&orig_file=A_Dmitriev__Weight.pdf

[Bored chemist]

The is another paper measuring weight of a heated thermal insulator decreases at increasing temperature.
http://intellectualarchive.com/getfile.php?file=ueSLj97NCAp&orig_file=A_Dmitriev__Weight.pdf

And a piss poor paper it is too.
It fails to mention  the words vacuum or convection- so it hasn't  dealt with the biggest problems involved in making such a measurement.
It also doesn't talk about how they addressed magnetic fields produced by the heating current.

It's a waste of bandwidth.

[Yaniv (OP)]

And a piss poor paper it is too.
It fails to mention  the words vacuum or convection- so it hasn't  dealt with the biggest problems involved in making such a measurement.
It also doesn't talk about how they addressed magnetic fields produced by the heating current.

It's a waste of bandwidth.

The outer vessels were specifically designed to reduce heat convection. You either didn't read or don't understand the paper. Weighing the apparatus in vacuum should completely eliminate heat convection.
The electric heater was switched on for 20 seconds and reduction in weight was recorded for several minutes so magnetic fields likely have a minimal effect on weight.

What happened to the laser method of heating ?

[Bored chemist]

Weighing the apparatus in vacuum should completely eliminate heat convection.

They didn't.
That's my point.

he outer vessels were specifically designed to reduce heat convection.

Reduce it to zero?

The electric heater was switched on for 20 seconds

And, when they switched it on the weight suddenly jumped down, even though any change in temperature would obviously be more gradual.
So...
Whatever the effect is, it's not temperature.

Nobody is going to bother doing an experiment they know will "fail" - even if it gives them an excuse to play with lasers.

[Yaniv (OP)]

Weighing the apparatus in vacuum should completely eliminate heat convection.
They didn't.
That's my point.

And my point is to conclude the experiment in vacuum to test a prediction of my theory against conservation of mass.

he outer vessels were specifically designed to reduce heat convection.
Reduce it to zero?

Almost zero. Repeating the experiment in vacuum will reduce heat convection to zero.

And, when they switched it on the weight suddenly jumped down, even though any change in temperature would obviously be more gradual.
So...
Whatever the effect is, it's not temperature.

What is your explanation for reduction in weight ?

Nobody is going to bother doing an experiment they know will "fail" - even if it gives them an excuse to play with lasers.

Even for £10K ?