Lesson Notes By Weeks and Term v4 - SHS 1
NUCLEAR PHYSICS
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NUCLEAR PHYSICS
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Subject: Physics
Class: SHS 1
Term: 2nd Term
Week: 20
Grade code: 1.4.2.LI.1
Strand code: 4
Sub-strand code: 2
Content standard code: 1.4.2.CS.1
Indicator code: 1.4.2.LI.1
Theme: ATOMIC AND NUCLEAR PH YSICS
Subtheme: NUCLEAR PHYSICS
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This lesson introduces the fascinating world of nuclear physics, focusing on the phenomenon of radioactivity. We will explore what happens inside the tiny nucleus of an atom that causes it to be unstable and release energy and particles. Understanding radioactivity is crucial because it has powerful applications that affect our daily lives here in Ghana, from generating electricity and treating cancer at hospitals like Korle Bu, to improving our agricultural produce at the Ghana Atomic Energy Commission (GAEC).
A. The Unstable Nucleus: The Root of Radioactivity
To understand radioactivity, we must first remember the structure of an atom. It has a tiny, dense, positively charged nucleus at its centre, containing protons (positive) and neutrons (no charge). The nucleus is surrounded by electrons (negative). Atomic Number (Z): The number of protons. It defines the element (e.g., any atom with 6 protons is Carbon). Mass Number (A): The total number of protons and neutrons (A = Z + N).
The nucleus is a crowded place. Protons, being positively charged, repel each other strongly. A force called the strong nuclear force acts like a powerful glue, holding the protons and neutrons together.
In some atoms, the balance between the repulsive force of the protons and the strong nuclear force is not perfect. This usually happens in atoms with very large nuclei (many protons and neutrons) or an imbalanced ratio of neutrons to protons. These nuclei are unstable. B. What is Radioactivity?