M 26 - M 35.1 Physics
Classical physics
| M26 | General, philosophy and miscellaneous (see also M35) | |
| M27 | Experimental physics | |
| M28 | Mechanics (see also M37 and M34.1) | |
| M28.1 | Statics | |
| M28.2 | Dynamics | |
| M28.3 | Hydrostatics | |
| M28.4 | Hydrodynamics. Aerodynamics | |
| M29 | Properties of matter and kinetic theory of gases | |
| M29.1 | Properties of matter | |
| M29.2 | Kinetic theory of gases | |
| M30 | Wave motion and sound. Acoustics | |
| M31 | Optics. Light. | |
| M32 | Heat | |
| M32.1 | Thermodynamics (see also M38) | |
| M32.2 | Statistical mechanics. Statistical physics | |
| M33 | Electricity and electromagnetic theory | |
| M33.2 | Magnetism | |
| M33.3 | Radio engineering. Microwaves etc |
Modern physics
| M34 | General modern physics/ Atomic physics. Atomic spectra. Molecular physics. Nuclear physics. | |
| M34.1 | Wave mechanics. Quantum mechanics (see also M30) | |
| M35 | Theoretical physics. Mathematical physics | |
| M35.1 | Relativity |