Energy and Appliances in the Home

BASIC SCIENCE JSS 2 THIRD TERM

Week 6

Topic: Energy and Appliances in the Home

Introduction

Energy lights our cities, powers our vehicles, and runs machinery in factories. It warms and cools our homes, cooks our food, plays our music, and gives us pictures on television.

Energy is defined as the ability or the capacity to do work. For any work that is done, energy is exerted or used.

We use energy to do work and make all movements. When we eat, our bodies transform the food into energy to do work. When we run or walk or do some work, we ‘burn’ energy in our bodies. Cars, planes, trolleys, boats, and machinery also transform energy into work. Work means moving or lifting something, warming or lighting something. There are many sources of energy that help to run the various machines invented by man.

Forms of Energy

Some of the many forms that energy takes are:

1. Mechanical energy, which includes
   • Potential energy, stored in a system or energy stored in an object
   • Kinetic energy, from the movement of matter or energy of a moving object
2. Radiant or solar energy, which comes from the light and warmth of the sun.
3. Thermal energy is energy associated with the heat of an object or energy of an object due to its temperature.
4. Chemical energy is an energy stored in the chemical bonds of molecules, energy stored in fuel (i.e. food) which is released when chemical reactions take place
5. Electrical energy is energy associated with the movement of electrons or energy transferred by an electric current
6. Electromagnetic energy is the energy associated with light waves (including radio waves, microwaves, x-rays, infrared waves).
7. Mass (or nuclear) energy is energy found in the nuclear structure of atoms.

Note: Potential energy is energy stored in an object. Chemical, nuclear, gravitational, and electrical are all stored energy. Kinetic energy does the work. Light, heat, motion, and sound are examples of kinetic energy.

What are the Sources of Energy?

Primary energy sources (meaning energy is created directly from the actual resource) can be classified in two groups: nonrenewable or renewable. Secondary sources are derived from primary sources.

Non-Renewable Energy Sources

Energy from the ground that has limited supplies, either in the form of gas, liquid or solid, are called nonrenewable resources. They cannot be replenished, or made again, in a short period of time. Examples include: oil (petroleum), natural gas, coal and uranium (nuclear). Oil, natural gas and coal are called “fossil fuels” because they have been formed from the organic remains of prehistoric plants and animals.

Renewable Energy Sources

Energy that comes from a source that’s constantly renewed, such as the sun and wind, can be replenished naturally in a short period of time. Because of this we do not have to worry about them running out. Examples include: solar, wind, biomass and hydropower. Currently, less than 2% of the world’s electricity comes from renewable resources. There is a global debate as to whether geothermal energy is renewable or nonrenewable.

Secondary Energy Sources

Energy that is converted from primary sources are secondary sources of energy. Secondary sources of energy are used to store, move, and deliver energy in an easily usable form. Examples include electricity and hydrogen.

Use of energy in the home

We have many uses of energy both in the home and at work. Lack of energy will mean that most of the activities we should have done with ease will be difficult to do.

We may not be able to do some of such activities. Some of the things we can do with energy are shown in the below

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 asks the pupils students to mention some home appliances and their sources of power
• The students are shown examples of energy that are renewable
• Students are encouraged to say what they have been taught about the early forces

Evaluation 

ASSESSMENT

1. Define energy?
2. What are the forms of energy?
3. List 3 sources of energy?
4. List 5 things we can do with energy at home
5. Define thermal energy
6. What is electrical energy
7. Explain kinetic energy
8. What is chemical energy
9. Explain solar energy
10. What is magnetism