Lesson Notes By Weeks and Term v4 - SHS 3
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 3
Term: 1st Term
Week: 15
Grade code: 3.1.3.LI.1
Strand code: 2
Sub-strand code: 1
Content standard code: 3.1.2.CS.1
Indicator code: 3.1.3.LI.1
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 explores the fundamental concepts of heat energy, a topic we experience daily in Ghana. From the heat of the sun in Tamale to the energy needed to cook our favourite banku or fufu, heat is a constant presence. Understanding the principles of heat allows us to explain why water takes a long time to boil, how sweating cools us down, and why coastal cities like Accra have different climates from inland cities like Kumasi. This lesson will move beyond the simple idea of "hot" and "cold" to provide a scientific and mathematical understanding of heat as a form of energy transfer, its measurement, and its effects on matter.
This section breaks down the core ideas of the lesson. We will explore what heat truly is and how we can measure and calculate its effects. A. Heat vs. Temperature
This is one of the most common points of confusion in thermodynamics. They are related, but not the same. Temperature (θ or T): Definition: Temperature is a measure of the degree of hotness or coldness of a body. Scientifically, it is a measure of the average kinetic energy of the particles (atoms or molecules) in a substance. Analogy: Imagine the students in a classroom. If they are all sitting calmly, their average energy is low (low temperature). If they are all jogging on the spot, their average energy is high (high temperature). Units: The SI unit for temperature is the Kelvin (K). However, the degree Celsius (°C) is more commonly used in daily life and in many school experiments. Measurement: Measured with a thermometer. Heat (Q): Definition: Heat is the total amount of internal energy transferred from a hotter body to a colder body due to the temperature difference between them. It is energy in transit. Analogy: Continuing the classroom analogy, temperature is the *average* energy of each student. Heat is the *total* energy of *all* the students combined. A large hall with 1000 students walking slowly (low temperature) might have more total energy (heat) than a small room with 10 students running fast (high temperature). Units: Since heat is a form of energy, its SI unit is the Joule (J). Key Point: An object does not *contain* heat; it contains internal energy. Heat is the name we give to the *transfer* of that energy.
| Feature | Temperature | Heat | | :--- | :--- | :--- | | Definition | Average kinetic energy of particles | Total energy transferred due to temperature difference | | SI Unit | Kelvin (K) | Joule (J) | | Measures | Degree of hotness/coldness | Quantity of energy | | Symbol | θ or T | Q | B. Specific Heat Capacity (c) Definition: The specific heat capacity of a substance is the quantity of heat energy required to raise the temperature of a unit mass (1 kg) of the substance by one degree (1 K or 1°C). What it means: A substance with a high specific heat capacity (like water) needs a lot of energy to get hot, but it also stores that energy very well and takes a long time to cool down. A substance with a low specific heat capacity (like a metal spoon) heats up very quickly but also cools down very quickly. Formula: `Q = mcΔθ` Where: Q = Quantity of heat transferred (in Joules, J) m = mass of the substance (in kilograms, kg) c = specific heat capacity of the substance (in J kg⁻¹K⁻¹ or J kg⁻¹°C⁻¹) Δθ = change in temperature (final temperature - initial temperature) (in K or °C). *Note: A change of 1 K is the same as a change of 1°C.*