All 8 short questions of 9th Class Physics Chapter 9, Nature of Science, with exam-ready answers in the book's words. Punjab Board new syllabus.
Exam-ready answers. Learn the meaning, then write them in your own words.
The knowledge about natural phenomena, processes and events around us, gained by observation and experiment.
The fundamental science of the constituents of the universe (matter, energy, space and time) and their mutual relationships and interactions.
Branches: mechanics, heat and thermodynamics, acoustics, optics, electromagnetism, quantum mechanics, relativistic mechanics, nuclear physics, particle physics, astronomy, cosmology, solid state physics.
Fields formed by the integration and interaction of physics with other subjects, where the principles and methods of physics are applied to them.
Examples: biophysics, medical physics, astrophysics, geophysics, climate physics, computational physics.
A possible explanation or educated guess proposed on the basis of observations, which can be tested by experiment.
Example: shadows of opaque objects are formed because light travels in straight lines.
| Theory | Law |
|---|---|
| A hypothesis verified by careful experiments | A theory tested many times and generally accepted as true |
| A logical explanation of the causes and effects of an event | A statement of how nature behaves, explaining the past and predicting the future |
| Example: light travels in straight lines | Example: law of rectilinear propagation of light |
Laser technology is based on the principles of atomic physics. It is used in medical diagnosis and treatment, metallurgy, industry, telecommunication and space exploration.
A theory is scientific only if it makes claims and predictions that can be tested and could possibly be proved false.
Importance: it keeps science free of vague or untestable claims, and separates real scientific theories from beliefs that can never be checked by experiment.
