Lesson Notes By Weeks and Term v4 - SHS 3
BASIC PHYSICS
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BASIC PHYSICS
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Subject: Physics
Class: SHS 3
Term: 1st Term
Week: 7
Grade code: 3.1.1.LI.3
Strand code: 1
Sub-strand code: 1
Content standard code: 3.1.1.CS.3
Indicator code: 3.1.1.LI.3
Theme: MECHANICS AND MATTER
Subtheme: BASIC PHYSICS
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Welcome, future scientists and engineers! Today, we are embarking on a journey across billions of kilometres and billions of years to answer one of humanity's oldest questions: Where did everything in the sky come from? We will explore how the very sun that gives us light and helps our cocoa and maize to grow was born, and how our Earth and its planetary neighbours were formed. Understanding this process is not just about space; it's about understanding the fundamental laws of physics—gravity, energy, and matter—that govern everything from the movement of a football to the creation of galaxies.
This entire cosmic story begins in one place: a nebula. Concept 1: The Nebula - The Cosmic Nursery Definition: A nebula is a gigantic cloud of gas and dust in interstellar space. Composition: It is primarily made of the two simplest and most abundant elements in the universe: Hydrogen (~75%) Helium (~24%) Trace amounts of other elements and dust particles (ice, rock, carbon compounds). Analogy: Think of a vast, cold harmattan cloud, but instead of just dust, it's filled with the raw ingredients to build stars and worlds. These nebulae are incredibly large, spanning many light-years across. Concept 2: Gravity - The Master Architect
The single most important force in this process is gravity. According to Newton's Law of Universal Gravitation, every particle with mass attracts every other particle. In the vastness of a nebula, these gravitational pulls are tiny. However, over millions of years, they work their magic.
The process needs a "push" or a trigger to get started. This can be the shockwave from a nearby exploding star (a supernova) or the gravitational pull from a passing star. This trigger causes a region of the nebula to become denser than its surroundings. Once this happens, its own gravity takes over.
The Formation of a Star (e.g., Our Sun)