Theories in physics that seemed to work but were wrong?

[Aidyan]

I'm trying to (re-)collect the physical theories that once were considered as a correct description of reality and worked to a certain degree, but were subsequently dismissed. I would say that the geocentric epicycle theory of Ptolemy could be considered an example. It correctly describes the path planets trace on the sky, but is obviously wrong since heliocentrism is true. Another example could be Bohr's atomic model. It furnishes the energy levels of the hydrogen atom. Later Sommerfeld extended it to electron elliptic orbits and was able to obtain further fine spectral lines of the H atom. And yet this model is no more than a historical curiosity. I suspect that there are many other examples of theories that seemed to 'save the appearances' but didn't work out. Can you tell of others?

 

[ZapperZ]

The Caloric theory.

Zz.

 

[anorlunda]

https://en.wikipedia.org/wiki/Germ_theory_of_disease#Miasma_theory

https://en.wikipedia.org/wiki/Superseded_scientific_theories
It is easy to underestimate the quantity of information available on Wikipedia.

 

[Vanadium 50]

Caloric.
Luminiferous ether.
Newtonian mechanics.

 

[fresh_42]

Ptolemy's planetary system.
Atomic models of Rutherford, Bohr.

 

[sophiecentaur]

Caloric.
Luminiferous ether.
Newtonian mechanics.

Why choose Newtonian Mechanics for the list? It's not even out of date for most practical purposes. In no way is it in the same category as Caloric.

 

[Vanadium 50]

Why choose Newtonian Mechanics for the list?

once were considered as a correct description of reality and worked to a certain degree

I think that's a fair description of what he asked for. Newtonian Mechanics works well in its domain, but fails spectacularly outside it - e.g. an electron in an atom.

 

[sophiecentaur]

I think that's a fair description of what he asked for. Newtonian Mechanics works well in its domain, but fails spectacularly outside it - e.g. an electron in an atom.

Oh yes - but caloric was complete rubbish even when it was current. Caloric even makes fifteen year old GCSE students giggle.

 

[Vanadium 50]

I don't know about "complete rubbish". Sadi Carnot developed the Carnot cycle using it.

 

[sophiecentaur]

I don't know about "complete rubbish". Sadi Carnot developed the Carnot cycle using it.

Perhaps I have interpreted the terms of the OP in the wrong way. Hindsight can be 100% accurate so perhaps that's where I'm wrong in applying it.
The Maths of a phenomenon can be arrived at by good or not so good models. Carnot spotted some variables that were future proof but his analogue / model of a 'substance' , although forgivable, was seriously adrift.

 

[MalcolmB]

The phlogiston theory.

 

[berkeman]

Hoyle's "continuous creation" or quasi-steady-state model of the Universe... https://en.wikipedia.org/wiki/Steady_state_model