For conventional superconductors, changing the mass of one element in an otherwise similar system changes the superconducting temperature at the expected rate.

“hope effect. Like if you take the same system but just different weight for one of the elements, you can see the superconducting temperature drops at the rate you expect. So that one is conventional. But then higher temperature superconductors like cuprates, like the ones that are above seventy seven Kelvin like ninety three Kelvin turns out don't obey that physics. Or we don't know what physics they obey.”