Understanding Thermal Energy: Conduction, Convection, Radiation

Lesson Plan for Basic Science and Technology

Subject: Basic Science and Technology
Class: JSS2
Term: Second Term
Week: Week 4
Age: 12-14 years
Topic: Thermal Energy
Sub-topic: Heat Flow, Conduction, Convection, and Radiation
Duration: 40 minutes

Behavioural Objectives

At the end of the lesson, students should be able to:

• Define thermal energy.
• Explain heat flow.
• Explain conduction, convection, and radiation.
• Identify examples of each type of heat transfer.

Keywords

• Thermal Energy
• Heat Flow
• Conduction
• Convection
• Radiation
• Temperature
• Heat Transfer
• Conductor
• Insulator
• Molecules

Set Induction

Teacher’s Prompt:
“Think about the last time you held a metal spoon that was left in a hot cup of tea. What did you feel when you touched the spoon? How do you think the heat got from the hot tea to the spoon and then to your hand? Today, we will explore how heat flows from one object to another. This process is called thermal energy transfer.”

Entry Behaviour

Students should have prior knowledge of energy transfer when work is done.

Learning Resources and Materials

• Whiteboard and markers
• Pictures/diagrams showing conduction, convection, and radiation
• Metal spoon, cup of hot water, and thermometer (for demonstration)
• Reference books (Lagos State Scheme of Work)

Building Background/Connection to Prior Knowledge

Students are familiar with energy transfer from previous lessons, including work done by energy. They have also learned about temperature and heat in basic science.

Embedded Core Skills

• Critical thinking
• Communication (discussion and contributions)
• Observation skills
• Practical application (through hands-on activities)

Instructional Materials

• Diagrams of heat transfer processes (conduction, convection, radiation)
• Metal spoon, water, fire source for demonstration
• Thermometer for temperature changes

Content

Thermal Energy:
Thermal energy refers to heat energy transferred from one object to another, depending on temperature differences. It flows from areas of high temperature to areas of low temperature.

1. Heat Flow
   • Heat is transferred in three main ways: conduction, convection, and radiation.
   • Heat flows from hotter areas to cooler ones.
   • Example 1: Heat from the sun to the Earth (radiation).
   • Example 2: Heat from a hot spoon to your hand (conduction).
   • Example 3: Heat moving through water in a pot (convection).
2. Conduction
   • The process where heat travels through a solid, especially metals, by vibration of particles.
   • Example: A spoon in a hot cup of tea. Heat moves from the tea to the spoon.
   • Good conductors: Metals (e.g., copper, aluminum).
   • Bad conductors: Wood, plastic.
3. Convection
   • The transfer of heat in liquids and gases by the movement of the fluid itself.
   • Example: In boiling water, hot water rises, and cooler water sinks.
4. Radiation
   • Heat transfer via electromagnetic waves that do not require a medium (like air or water).
   • Example: Heat from the sun reaches the Earth through space (vacuum).

Examples

1. Conduction:
   • A metal rod heated at one end.
   • A pan on a stove where heat is transferred to the food.
   • A person touching a hot iron.
2. Convection:
   • Hot air rising near a heater.
   • Water heating in a kettle.
   • Air in the atmosphere warming and rising near the Earth’s surface.
3. Radiation:
   • Heat from the sun warming your skin.
   • Heat from a fire.
   • Microwave heating food using radiation.

Evaluation

Fill-in-the-Blank Questions:

1. The process of heat transfer through solids is called __________.
   a) Radiation
   b) Conduction
   c) Convection
2. Heat moves from a __________ area to a __________ area.
   a) Cold, hot
   b) Hot, cold
   c) Warm, cool
3. The process of heat transfer in liquids is known as __________.
   a) Convection
   b) Conduction
   c) Radiation
4. A good conductor of heat is __________.
   a) Wood
   b) Copper
   c) Plastic
5. Heat transfer that does not require a medium is called __________.
   a) Convection
   b) Conduction
   c) Radiation
6. __________ is a good example of convection.
   a) A metal rod
   b) Boiling water
   c) A hot spoon
7. The heat from the sun reaches the Earth through __________.
   a) Conduction
   b) Convection
   c) Radiation
8. __________ is a bad conductor of heat.
   a) Mercury
   b) Copper
   c) Water
9. Heat moves from __________ objects to __________ objects.
   a) Hot, cold
   b) Cold, hot
   c) Warm, cool
10. __________ is transferred by electromagnetic waves.
    a) Radiation
    b) Convection
    c) Conduction

Class Activity Discussion

FAQs and Answers:

1. What is thermal energy?
   • Thermal energy is the heat energy transferred from one object to another.
2. How does conduction work?
   • Heat moves through solids by vibration of particles.
3. Why does heat travel from hot to cold?
   • Heat flows from areas of higher energy to lower energy.
4. What are good conductors of heat?
   • Metals like copper, iron, and aluminum are good conductors.
5. Can heat travel through a vacuum?
   • Yes, heat can travel through a vacuum by radiation.
6. How does convection occur?
   • Heat moves through liquids and gases by the movement of molecules.
7. Can heat transfer occur in gases?
   • Yes, gases can conduct heat through convection.
8. What is an example of radiation?
   • Heat from the sun reaching Earth is an example of radiation.
9. Why is water a bad conductor of heat?
   • Water does not allow heat to move through it easily.
10. How is heat transferred through a metal spoon?

• Heat travels from the hot liquid to the spoon and then to your hand.

Teacher’s Activities

• The teacher revises the previous topic of energy transfer.
• Introduces the new topic on heat flow and thermal energy.
• Demonstrates examples of conduction, convection, and radiation using simple tools.
• Guides student discussions and contributions while correcting misconceptions.

Learners’ Activities

• Students ask questions and contribute answers during discussions.
• Engage in hands-on activities, such as touching metal spoons and observing boiling water.
• Complete the fill-in-the-blank questions individually or in pairs.

Assessment (Evaluation Questions)

1. Define thermal energy.
2. Explain how heat flows through solids.
3. Describe how heat moves in liquids.
4. What is conduction?
5. How does radiation work?
6. Give an example of convection.
7. What is a good conductor of heat?
8. How does heat move from one object to another?
9. What is the importance of thermal energy?
10. Name one bad conductor of heat.

Conclusion

• The teacher goes around to mark the students’ responses.
• Provides feedback, reinforcing the key points on thermal energy, heat flow, and types of heat transfer.

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