I can foresee a problem here.

If we check

Kaye & Laby's Tables Of Physical & Chemical Constants with respect to the realisation of SI units, we learn that it is possible, with careful measurement, to determine a mass of the order of 1 kg to around 1 part in 10

9, which sounds fairly impressive. However, other SI units are determinable to one part in 10

12 or better. Part of the problem is that we still have to use weighing balances for mass determination, whilst the metre and the second are now defined in terms of extremely high-precision radiation at tightly defined frequencies, and stabilised lasers can push the determination of time and length, in precise work, to better than 1 part in 10

15. Achieving that level of precision with mass measurements is, at the moment, beyond our remit for macroscopic objects.

Now, if we impart to, say, a 1 kg block of pure metal, enough heat energy to raise the temperature by a given amount, then that heat energy is related to temperature by the following:

E = cmT

where E is the heat energy input into the material, c is the specific heat capacity by mass, m is the mass, and T is the change in temperature from the starting temperature. So, for example, we can work out how much heat energy is needed to raise the temperature of a 1 kg cube of copper by 100 Kelvins. We do this by feeding into the above equation:

c = 385 J kg

-1 K

-1m = 1 kg

T = 100 K

This gives us a value for the heat energy required of 38,500 J.

However, taking an elementary approach, we can then use E=mc

2 to work out what mass change is associated with this energy, by rearranging the equation to give:

m = E/c

2Here, c is the speed of light

in vacuo, which is 299,792,458 m s

-1. Therefore, the mass change associated with that energy input is:

m = 38,500 ÷ (299,792,458)

2 = 4.283 × 10

-13 kg

Determining that this mass change has occurred, whilst eliminating any other effects that might be present, is simply beyond the remit of current instruments.

This is before we take into account, that in

precise work, the specific heat capacity is not a fixed value, but is itself a function of temperature, though one that changes slowly in value therewith. For example, from

here, we see that the specific heat capacity for water, decreases slightly from 0°C through to around 48°C, then starts increasing again, though unless you plot the graph with a suitable scale, the curved shape of the function is not readily apparent.

Then there's the matter of desigining an experiment to perform measurement of this change, whilst simultaneously eliminating other effects,

even if the inherent mass measurement problem is solved. If it becomes possible to measure changes in mass to better than 1 part in 10

15 for macroscopic objects in the future, desigining an experiment to measure mass change arising from heat energy input, whilst eliminating effects such as convection in air, is going to be time consuming, expensive, and possibly require some ingenuity.

So it's hardly surprising that there have been no reports in the literature of experiments of this sort, because at the moment, they are

not possible. And that inherent mass measurement problem, is

also going to impact upon any hypothesis that contains a claim about the relationship between temperature and measured mass. Anyone claiming to measure a mass change to better than 1 part in 10

9 can be dismissed immediately, on the basis that this simply isn't possible.

Of course, as has already been presented here at least once, experiments involving changes in measured mass due to convective forces have already been conducted, but we already know that convective forces can exert considerable macroscopic effects. Just ask any glider pilot.

Quite simply, any hypothesis involving mass changes that are of the same order of magnitude as those arising from relativistic concerns, will be untestable, because the mass changes are too small to measure with current technology, and any hypothesis involving

measurable effects of this sort not arising from known effects such as convection, had better be subject to proper diligence on the experimental front, or else it'll be as discardable as creationism.