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.4
Strand code: 1
Sub-strand code: 1
Content standard code: 3.1.1.CS.3
Indicator code: 3.1.1.LI.4
Theme: MECHANICS AND MATTER
Subtheme: BASIC PHYSICS
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Welcome, future scientists and engineers! Today, we journey beyond our Earth, beyond our Solar System, to the vast and magnificent structures that make up our universe. From looking up at the night sky in a village far from the city lights of Accra or Kumasi, people have always wondered about the stars. What are they? How are they grouped? This lesson explores these cosmic structures – galaxies, nebulae, and constellations. Understanding them not only satisfies our curiosity but also connects us to the knowledge of our ancestors, who used the stars for navigation, farming, and storytelling.
2.1. What is a Galaxy?
A galaxy is a massive, gravitationally bound system consisting of stars, stellar remnants (like white dwarfs and neutron stars), interstellar gas, dust, and dark matter. Think of it as a giant "city" of stars. Our own solar system is located within a galaxy called the Milky Way.
A typical galaxy has the following components: Stars: Billions to trillions of them. Gas and Dust (Interstellar Medium): The raw material for forming new stars. Dark Matter: An invisible substance that provides most of the galaxy's mass and gravitational pull. We can't see it, but we know it's there because of its gravitational effects. A Supermassive Black Hole: Most large galaxies are believed to have a supermassive black hole at their centre. 2.2. Types of Galaxies
Galaxies are classified based on their visual shape, a system developed by Edwin Hubble.