Thermal Energy

Subject: Basic Science  JSS 2 THIRD TERM

Class: JSS 2 

Week : 1 & 2

Topic: Thermal Energy

Sub-topic:

Transfer of Heat Energy

Methods of Teaching 

• Role modelling
• Questions and Answers
• Explanation
• Discussion
• Recitation
• Imitation
• Story Telling
• Dramatization

Instructional Materials 

• Bunsen Burner
• Electric iron
• Boiling ring
• Firewood

Previous Knowledge: The pupils have previous knowledge of

that was taught in their previous lesson.

Behaviour objectives : By the end of the lesson, learners will be able to

• Explain energy
• Define thermal
• Say if thermal energy is the same as heat energy
• Explain the process of heat energy transfers
• List and explain methods of heat transfer
• Define Conduction, Convection and Radiation

Content

Introduction

Energy transfer is the process of transmitting or transferring energy from one place to another. The word thermal means heat. Thermal energy is the transfer of heat from one place to another.

Heat Flow

Energy transfer means that energy moves from one place to another (without changing form). The process of heat flow from the sun to us is referred to as radiation. The process of heat flow from the soup to the spoon discussed is referred to as conduction. There is the third process of heat flow known as convection. Therefore, heat flow means that heat energy is transferred from a hotter part of an object to the cooler part of the object. Heat is a form of energy that flows from a hot area to a cold one. When you are in the hot sun, you feel hot. The heat travels from the sun through the atmosphere to your skin. When you put a kettle of cold water on fire, the water gets hot. The heats flows or travels from the fire through the kettle into the water.

Transfer of Heat Energy

The three processes of heat transfer are conduction, convection and radiation.

Conduction

When particles in a matter (or substance preferably a metallic substance) are heated, the particles vibrate, hitting the successive ones (which are not in contact with the source of heat). This raises their temperature until all the particles in the metallic substances are heated up. In this way, heat is being conducted along the metallic substance and this process is called conduction.

Usually, heat flows from a hot to a cold body. You know that heat is a form of energy and a hot body has energy stored up (in form of potential energy) in it. In order to convert this potential energy into kinetic energy, heat then passes to another particle which has lower energy. Therefore, a hot body must lose heat energy to a cooler one.

There are good conductors and bad conductors of heat.

Good conductors of heat are substance s, which conduct heat readily; all metals are good conductors of heat.

Bad conductors are substances that do not conduct heat readily. Liquids and gases are bad conductors of heat. Water is an example of a bad conductor of heat. But mercury is a metallic liquid, hence it conduct heat readily.

Convection

Heat transfer in convection is peculiar with liquids. The heat flows from the bottom of a liquid container to the top by the actual movement of the liquid molecules. This transfer of heat by the movement of liquid molecules is known as convection

Radiation

Radiation is a method of heat transfer that does not require material medium for transmission. Heat energy is transmitted by means of waves. Heat energy from the sun reaches us by radiation. Heat can travel in invisible waves from hot places to cooler places. Heat travelling this way does not need any medium (solids, liquids or gases) to travel through. Heat can travel through a vacuum. A vacuum is a space in which there is nothing at all, not even air. There is a vacuum in space between the earth and the sun. The heat from the su travels through this vacuum to the earth and through the earth to other objects.

Summary of the Three Types of Heat Transfer

Diagram of the Three Types of Radiation

Presentation: 

The topic is presented step by step

Step 1: The class teacher revises the old topic

Step 2: The class teacher introduces the new topic

Step 3: The class teacher allows the pupils to give their own contributions and gives room for pupils” participation

Class Teacher and Pupils Activities. Interaction or Participation 

This involves class teacher and pupils’ interaction, conversation, imitation or modeling through discussion, play method or just by recitation or asking and answering questions that are related to the topic that has just been taught

• The class teacher tells the learners that fire is the major source of heat
• The class teacher let the students know that the sun is the major supplier of heat on earth
• Let the pupils know that they can talk, play or discuss with each other

Evaluation

Part A. 

Objectives 

1. Thermal energy is also known as __________ energy (a) friction (b) kinetic (c) heat
2. __________ is a device that can be used to measure heat (a) thermometer (b) hydrometer (c) speedometer
3. Therm energy can be used to produce all of the following except __________ (a) heat (b) fire (c) animal
4. Thermal means __________(a) danger (b) risk (c) heat
5. Any material that allows the free flow of heat is known as a __________(a) insulator (b) conductor (c) radiator
6. The most important source of heat energy on planet earth is the __________(a) mars (b) sun (c) motor car
7. How does thermal heat energy move __________ (a) from top to bottom (b) from cold to hot (c) from side to side
8. The degree of unit of measurement for heat is __________ (a) kilometre (b) celsius (c) ohms
9. Any material that does not allow the flow of heat is said to be an __________(a) insulator (b) insulin (c) incubator
10. __________ is a method of heat transfer that does not require material medium for transmission (a) Radiation (b) Convection (c) Conduction

Part B 

Theory 

1. Define energy
2. Define thermal energy
3. Say if thermal energy is the same as heat energy
4. Explain three processes of heat energy transfers
5. List and explain two methods of heat transfer
6. Define Conduction, Convection and Radiation

ASSESSMENT

1. Define Radiation?
2. The three processes of heat transfer are___
3. What is energy transfer?
4. What is the meaning of Conduction

Conclusion

The class teacher goes round to mark and he or she does the necessary corrections