Lesson Notes By Weeks and Term v4 - SHS 2
HEAT
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
HEAT
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Physics
Class: SHS 2
Term: 1st Term
Week: 12
Grade code: 2.1.4.LI.2
Strand code: 2
Sub-strand code: 1
Content standard code: 2.1.4.CS.1
Indicator code: 2.1.4.LI.2
Theme: ENERGY
Subtheme: HEAT
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
This lesson introduces the concepts of Heat Capacity and Specific Heat Capacity. Understanding these concepts is crucial for explaining everyday phenomena we observe in Ghana. For instance, why does the sea at Labadi beach feel cool during a hot afternoon while the sand is scorching hot? Why does a pot of water take a long time to boil for our banku, but the metal pot itself gets hot very quickly? This lesson will provide the scientific principles to answer these questions and more. By understanding how different materials absorb and retain heat, we can appreciate its application in cooking, climate, and engineering.
A. Recap: Heat vs. Temperature Before we proceed, let's remember the difference between two key terms: Heat (Q) is the total thermal energy that flows from a hotter object to a colder object. It is a form of energy, measured in Joules (J). Temperature (θ or T) is a measure of the degree of hotness or coldness of a body. It indicates the average kinetic energy of the particles in the substance. It is measured in degrees Celsius (°C) or Kelvin (K).
Think of it this way: a small cup of boiling water and a large pot of boiling water are at the same *temperature* (100°C), but the large pot contains much more *heat* energy. B. Heat Capacity (C) Heat capacity is the amount of heat energy required to raise the temperature of an entire object or substance by one degree Celsius (1°C) or one Kelvin (1K). Formula: `C = Q / Δθ` C is the Heat Capacity Q is the heat energy supplied (in Joules, J) Δθ is the change in temperature (in °C or K). `Δθ = θ_final - θ_initial` Unit: Joules per Kelvin (J/K) or Joules per degree Celsius (J/°C).
Heat capacity depends on the mass and the type of material. A large cast iron pot (*dadasen*) will have a much higher heat capacity than a small one, even though they are made of the same material. C. Specific Heat Capacity (c) This is a more useful property because it is specific to the material itself, regardless of the object's size or mass.
Specific Heat Capacity (c) of a substance is the amount of heat energy required to raise the temperature of a unit mass (1 kg) of that substance by one degree Celsius (1°C) or one Kelvin (1K). Formula: `c = Q / (m * Δθ)` This formula can be rearranged to the more common form: `Q = mcΔθ` Q = Heat energy absorbed or lost (J) m = mass of the substance (kg) c = specific heat capacity of the substance (J/kg°C or J/kgK) Δθ = change in temperature (°C or K)