Classical Physics:

1. Mechanics: Study of motion, forces, and energy.

2. Thermodynamics: Study of heat and its relation to other forms of energy.

3. Electromagnetism: Study of electric and magnetic phenomena.

4. Optics: Study of light and its properties.

5. Acoustics: Study of sound and its properties.

Modern Physics:

6. Quantum Mechanics: Study of the behavior of matter and energy at the atomic and subatomic levels.

7. Relativity: Study of gravity and the nature of space and time.

8. Nuclear Physics: Study of the structure and properties of atomic nuclei.

9. Particle Physics: Study of the fundamental particles that make up matter.

10. Astrophysics: Study of celestial objects and phenomena.

Other Fields:

11. Materials Science: Study of the properties and applications of materials.

12. Geophysics: Study of the Earth's physical properties and processes.

13. Atmospheric Science: Study of the Earth's atmosphere and its weather patterns.

14. Oceanography: Study of the oceans and their physical properties.

15. Biophysics: Study of the physical principles underlying biological systems.

This is not an exhaustive list, and there are many other specialized fields within physical science.