Unit 1: Physics and Human Society

Physics is a branch of natural science that explores the fundamental aspects of the universe to describe its basic mechanisms. This unit introduces the definition, nature, and various branches of physics while explaining its relationship to other scientific disciplines. It also highlights the historical contributions of prominent physicists whose revolutionary discoveries transitioned the field from classical to modern physics.

1.1 Definition and Nature of Physics

• Physics is a branch of natural science aimed at describing the fundamental aspects of our universe, including the properties of things and the processes they undergo.
• The word originates from the Greek word phusis, which means nature.
• It attempts to describe the basic mechanisms that make the universe behave the way it does.
• Physics is essential for understanding the working principles of modern technology such as computers, smartphones, airplanes, and space-rockets.
• A person who studies physics is called a physicist.
• Career opportunities for physicists include fields such as transportation, aviation, medicine, forensic science, military science, and meteorology.

1.2 Branches of Physics

• Mechanics: Deals with the motion of objects with or without the reference of force.
  • Classical mechanics: Deals with the laws of motion of forces and physical objects.
  • Quantum mechanics: Deals with the behavior of the smallest particles like neutrons, protons, and electrons.
• Acoustics: The study of sound, including its transmission, production, and effects.
• Optics: Deals with the behavior, propagation, and properties of light.
• Thermodynamics: Studies thermal energy and the transfer of heat.
• Electromagnetism: Deals with electromagnetic forces such as electric fields, magnetic fields, and light.
• Nuclear physics: Deals with the structure, properties, and reactions of the nuclei of atoms.
• Astrophysics: Employs physics principles to study astronomical objects and phenomena.

1.3 Related Fields to Physics

• Chemistry: Rooted in atomic and molecular physics to understand interactions between atoms and molecules.
• Engineering: Architecture uses physics for structural stability, acoustics, and lighting; other branches apply it to machine design.
• Geology: Relies on physics for radioactive dating, earthquake analysis, and heat transfer across the Earth.
• Biophysics: Applies physics methods to study biological organisms and systems.
• Geophysics: Applies physics principles to the study of the Earth.
• Medical Physics: Involves physics principles in diagnostics and therapy, such as X-rays, MRI, and ultrasonic measurements.

1.4 Historical Issues and Contributors

• Classical physics: The stage of physics development from the Renaissance to the end of the 19th century.
• Modern physics: The transformation of physics triggered by revolutionary discoveries at the beginning of the 20th century.
• Isaac Newton: Formulated the three laws of motion and the principle of universal gravitation, laying the foundation for classical mechanics.
• Michael Faraday: Invented the first electric generator and made major contributions to electromagnetism by producing mechanical motion from magnets.
• James Prescott Joule: Discovered the relationship between heat and mechanical work, leading to the law of conservation of energy.
• Marie Curie: Pioneered research in radioactivity and nuclear physics; she discovered the elements polonium and radium.
• Albert Einstein: Developed the theory of relativity and contributed significantly to quantum mechanics.

Process: Using Google Maps for Location and Direction

1. Open the Google Maps software application on an Android phone, tablet, or computer.
2. Search for a specific place or tap a location on the map.
3. Tap the “directions” icon located at the bottom right of the screen.
4. To add a destination, go to the top right, tap “more,” and then select “add a stop”.

Key Terminology

• Physics: A branch of natural science describing the basic mechanisms of the universe.
• Natural science: The broader category of science that includes biology, chemistry, and physics.
• Physicist: A person who studies physics.
• Mechanics: The branch of physics dealing with the motion of objects.
• Quantum mechanics: Physics dealing with the behavior of subatomic particles.
• Classical mechanics: Physics dealing with laws of motion and macroscopic objects.
• Acoustics: The study of sound and its properties.
• Optics: The study of light and its behavior.
• Thermodynamics: The study of thermal energy and heat transfer.
• Electromagnetism: The study of electric and magnetic fields.
• Nuclear physics: The study of the nuclei of atoms.
• Astrophysics: The study of astronomical objects using physics.
• Biophysics: The application of physics to biological systems.
• Geophysics: The application of physics to the study of the Earth.
• Medical Physics: The use of physics in medical diagnostics and therapy.
• Classical physics: Physics as it developed until the end of the 19th century.
• Modern physics: Physics characterized by 20th-century discoveries like relativity and quantum mechanics.