Is the Mass Defect in Heavy Nuclei Well Supported by Scientific Evidence?

[granpa]

how sure are we that heavy nuclei are less massive than the sum of their constituent particles? the masses of atoms are determined by sending their ions through magnetic fields and measuring how much they are deflected. how do we know that heavy nuclei don't simply produce, at any given velocity, slightly stronger magnetic fields than lighter nuclei?

 

[malawi_glenn]

The nuclei bend in Magnetic fields due to their own charge. The magnetic field is external, the only thing you are measuring of the nuclei is their charge vs. mass ratio.

So there is not a magnetic field beeing produced by the nucleus.. only electric charge, which electric field is additative.

There was a crackpot here almost a year ago who claimed that the other protons in the nuclei whould sheild the charge from the protons inside, hence resulting in a smaller net charge than the sum of the constituent protons... but as he didn't know, equal charges do not screen...