Classical Physics

1. Classical physics: Classical physics deals with things we can see and experience in everyday life. It covers how objects move, how heat works, electricity and magnetism, and how light behaves. This branch of physics was developed before we understood very small things (quantum mechanics) or very fast things (relativity). It assumes that time and space are fixed and unchanging, and that we can predict exactly how things will behave if we know all the forces acting on them.

2. Classical mechanics: Classical mechanics is the study of how objects move and why. It’s based on three important rules called Newton’s Laws:
   1. First Law: Objects don’t change their motion unless something pushes or pulls them. This is why things stay still or keep moving in a straight line unless a force acts on them.
   2. Second Law: The more force you apply to an object, the more it speeds up. Heavier objects need more force to speed up than lighter ones.
   3. Third Law: When you push on something, it pushes back on you just as hard. This is why when you jump, you push down on the ground, and the ground pushes you up.
3. Energy in classical mechanics: Energy comes in different forms:
   1. Kinetic energy: The energy an object has because it’s moving.
   2. Potential energy: Stored energy, like when you lift something up - it has the potential to fall.
   3. Mechanical energy: The total of kinetic and potential energy.

   A key idea is that energy can’t be created or destroyed, only changed from one form to another.

4. Thermodynamics: Thermodynamics is the study of heat and energy. It has three main rules:
   1. First Law: Energy can’t be created or destroyed, only changed from one form to another.
   2. Second Law: In any process, some energy always becomes unusable, often as heat. Things naturally tend to become more disorganized over time.
   3. Third Law: As things get extremely cold, they become more organized.
5. Electromagnetism: Electromagnetism studies electricity and magnetism, which are actually two sides of the same coin. Key ideas include:
   1. Electric charges create electric fields around them.
   2. Moving electric charges create magnetic fields.
   3. Changing magnetic fields can create electric currents.
   4. Light is a wave made of electric and magnetic fields.
6. Classical optics: Classical optics is the study of light, treating it as a wave. It explains:
   1. Reflection: Light bouncing off surfaces.
   2. Refraction: Light bending when it passes from one material to another, like air to water.
   3. Diffraction: Light spreading out when it passes through small openings.

7. Newton’s law of gravitation: Newton’s law of gravitation explains how everything with mass pulls on everything else with mass. The bigger the masses and the closer they are, the stronger the pull. This is why planets orbit the sun and why things fall to the ground.

8. Classical waves and oscillations: This part of physics deals with repeating motions and disturbances that travel through space or materials. Examples include sound waves and water waves. Key concepts are:
   1. Frequency: How often the wave repeats.
   2. Wavelength: The distance between one peak of the wave and the next.
   3. Amplitude: How big the wave is, which relates to how much energy it carries.

In summary, classical physics gives us a way to understand and predict how things in our everyday world behave. While it doesn’t work for very small things or things moving close to the speed of light, it’s incredibly useful for most situations we encounter in daily life.